Occasionally, his syntheses present new and even revelatory ways of seeing things.
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But our politics depends on creative syntheses and political leaders who take chances.
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Then, there are newer syntheses of the surreal and symbolist, via George Condo, Damien Hirst, and Richard Prince.
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These are syntheses of the research evidence that bring together all the highest-quality studies to come to more fully supported conclusions.
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Fourteen 17th-century paintings of arhats are vividly realized and still brightly colored, impressive syntheses of individual detail and intense formal stylization.
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We started with systematic reviews: syntheses of the research evidence that bring together a bunch of studies to come to more fully supported conclusions.
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It's these natural syntheses that highlighted the surprisingly sympatico pairing of these two disparate music worlds, both governed by pure feeling on the largest scale.
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It showcases whomever the journalist happened to talk to on a given day, wherever she ended up going, rather than any hard-earned judgments or syntheses.
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Its strongest chapters — on 'A Raisin in the Sun' and Lorraine's coming into her own as a public intellectual — are masterly syntheses of research and analysis.
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Its strongest chapters — on "A Raisin in the Sun" and Lorraine's coming into her own as a public intellectual — are masterly syntheses of research and analysis.
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While Monáe's knowledge of music history and her facility with genre have produced elegantly complex and information-rich songs, these are retro syntheses, committed to interpolating history.
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Meager's work correctly suggests we should focus more on syntheses of studies than specific individual studies, and this is one of the best of the latter camp I saw this decade.
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The papers were also systematic reviews and meta analyses, or syntheses of the research evidence that bring together a bunch of studies with the goal of coming to more fully supported conclusions.
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" In their email, Los Hemocionales write: "We're fed up with discourses that are in no way syntheses of our time and don't reflect the true concerns of art that ask about our here and now.
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From the ebullient rollerdisco surge of "Run Away With Me" to the lurid wobble of "Warm Blood," Emotion soars speedily, with an almost embarrassing confidence, through a set of breathlessly sequenced, brightly melodic syntheses of yearning and excitement.
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Amid such conflict, in my work with patients and in my writing, I do my best to explore contradictions, look for specifics amid abstractions, search for syntheses and, in the face of real uncertainty, advocate for polyphony, a multiplicity of explanatory perspectives.
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These powerful and original syntheses of Synthetic Cubism and Expressionism — enlivened by his encounters with Robert Delaunay, in Paris, and, with the Blaue Reiter group in and around Munich, including Wassily Kandinsky, Gabriele Münter, August Macke, and Franz Marc — founded Hartley's reputation as a modernist innovator.
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LinkExample: Organic Syntheses, Organic Syntheses, Coll. Vol. 9, p.169 (1998); Vol. 72, p.
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Link Acenaphthylene forms a useful catalyst derived from triruthenium dodecacarbonyl.Example: Organic Syntheses, Organic Syntheses, Vol. 82, p.188 (2005).
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One example of an Ru-arene complex is (cymene)ruthenium dichloride dimer, which is the precursor to a versatile catalyst for transfer hydrogenation.Organic Syntheses, Organic Syntheses, Vol. 82, p.10 (2005).
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Inorganic Syntheses is a book series which aims to publish "detailed and foolproof" procedures for the synthesis of inorganic compounds.Inorganic Syntheses Organization. Although this series of books are edited, they usually are referenced like a journal, without mentioning the names of the checkers (referees) or the editor. A similar format is usually followed for the series Organic Syntheses.
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Isobe's Synthesis of Okadaic Acid. To date, several studies have been performed toward the synthesis of okadaic acid and its derivatives. 3 total syntheses of okadaic acid have been achieved, along with many more formal syntheses and several total syntheses of the other dinophysistoxins. The first total synthesis of okadaic acid was completed in 1986 by Isobe et al.
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Several routes have been developed for the syntheses of aziridines (aziridination).
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As of 2006, five additional research groups had reported successful total syntheses of paclitaxel: Wender et al. in 1997, and Kuwajima et al. and Mukaiyama et al. in 1998 with further linear syntheses, and Danishefsky et al.
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Two scalable and efficient total syntheses of huperzine A have been reported.
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Several syntheses of vancosamine have been published.Hauser, F. M., Ellenberger, S. R., Glusker, J. P., Smart, F. J., Carrell, H. L. "Stereoselective Syntheses or +/- Daunosamine, +/- Vancosamine, and +/- Ristosamine from Acyclic Precursors." J. Org. Chem. 1986, 51, 50-57.
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John Wiley & Sons, 1970. , . In 1977, Buehler and Pearson published a second volume of Survey of Organic Syntheses. The second volume expands the contents of the first, adding new methods of syntheses not previously mentioned in the first volume.
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The first total syntheses of katanosin B (lysobactin) have been described in 2007.
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Chemical syntheses of spironolactone and its analogues and derivatives have been described and reviewed.
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H. T. Clarke and Letha Davies Behr "Succinimide" Organic Syntheses 1936, volume 16, 75.
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He uses his chemistry notebooks from Cambridge when he develops new syntheses of drugs.
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11α-OHP is used as a precursor in chemical syntheses of cortisone and hydrocortisone.
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L. Dieck, E. J. Peterson, A. Galliart, T. M. Brown, T. Moeller "Tetraethylammonium, Tetraphenylarsonium, and Ammonium Cyanates and Cyanides" Inorganic Syntheses, 1976, Vol. 16, pp. 131–137. and trichlorostannate (Et4NSnCl3).G. W. Parshall "Tetraethylammonium Trichlorogermanate(1−) and Trichlorostannate(1−)" Inorganic Syntheses, 1974, Vol.
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Online article and cyclohexanone oxidation to 1,2-cyclohexanedione.Organic Syntheses, Coll. Vol. 4, p. 229 (1963); Vol.
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Ed. Engl., 6, 733 (1967). Examples are the synthesis of tert-butyl diazoacetateOrganic Syntheses, Coll. Vol.
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A "synthetic tree" can be constructed because each compound and also each precursor has multiple syntheses.
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H. C. Miller, E. L. Muetterties "Borane Anions" Inorganic Syntheses, 1967, Volume 10, pp. 81-91.
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It is prepared by reaction of disulfur dichloride with ammonia,Becke-Goehring, Margot; Fluck, Ekkehard "Heptasulfur imide" Inorganic Syntheses 1966, vol. 8, 103-5. although other methods have been developed.Bojes, J.; Chivers, T.; Drummond, I. "Heptathiazocine(heptasulfurimide) and tetrabutylammonium tetrathionitrate" Inorganic Syntheses (1978), 18, 203-6.
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Light- mediated syntheses have also been explored where light can promote formation of various silver nanoparticle morphologies.
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It is also used as a chiral ligand in organic chemistry, especially in syntheses involving organolithium reagents.
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9, p.4 (1929). (Article)Clarke, H. T.; Bean, H. J. Organic Syntheses, Coll. Vol. 2, p.
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Bromopentacarbonylrhenium(I) is an inorganic compound of rhenium, commonly used for the syntheses of other rhenium complexes.
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Lupinine has a chiral carbon atom; therefore, total syntheses of lupinine need to be enantioselective for (-)-lupinine in order to provide the biologically active product. The first racemic total synthesis of lupinine occurred in 1937 by Clemo, Morgan, and Raper. Six more total syntheses of lupinine followed between 1940-1956, with the first enantioselective synthesis of lupinine occurring in 1966 by Goldberg and Ragade. Since that initial enantioselective synthesis, there have been numerous total syntheses of both enantio-pure and racemic lupinine.
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9, p. 396 (1998); Vol. 71, p. 181 (1993) Online article β-PineneOrganic Syntheses Coll. Vol. 6, p.
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Solvents find various applications in chemical, pharmaceutical, oil, and gas industries, including in chemical syntheses and purification processes.
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As is shown by the various syntheses of the base, it is the methyl hydroxide of dimethyl glycocoll.
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Trisubstituted derivatives, e.g. triethylboron are monomers.Brown, H. C. “Organic Syntheses via Boranes” John Wiley & Sons, Inc. New York: 1975. .
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Tributylamine is used as a catalyst (proton acceptor) and as a solvent in organic syntheses and polymerization (including polyurethanes).
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Protein and RNA syntheses were examined during hyphal germ tube emergence from sporangiospores of a dimorphic phycomycete, Mucor racemosus.
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Syntheses of kaolinite at high temperatures (more than ) are relatively well known. There are for example the syntheses of Van Nieuwenberg and Pieters (1929); Noll (1934); Noll (1936); Norton (1939); Roy and Osborn (1954); Roy (1961); Hawkins and Roy (1962); Tomura et al. (1985); Satokawa et al. (1994) and Huertas et al. (1999).
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Survey of Organic Syntheses, Volume II. Calvin A. Buehler, Donald E. Pearson and Paul F. Hudrlik. John Wiley & Sons, 1977. , .
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The Friedländer synthesis is a chemical reaction of 2-aminobenzaldehydesOrganic Syntheses, Coll. Vol. 3, p. 56 (1955); Vol. 28, p.
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Cryptophycins were first isolated from cyanobacteria but have subsequently been produced by chemical synthesis. Chemoenzymatic syntheses have also been reported.
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Some latter-day examples include Wender's, Holton's, Nicolaou's, and Danishefsky's total syntheses of the anti-cancer therapeutic, paclitaxel (trade name, Taxol).
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B. E. Hoogenboom, O. H. Oldenziel, and A. M. van Leusen "Toluenesulfonylmethyl isocyanide" Organic Syntheses, Coll. Vol. 6, p.987 (1988).
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Gilman concentrated on preparing volatile uranium derivatives, mainly dealing with alkoxides, and the syntheses of species with potential anti-malarial activities.
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58 (1958). (Article) # Uff, B. C.; Kershaw, J. R.; Neumeyer, J. L. Organic Syntheses, Coll. Vol. 6, p. 115 (1988); Vol.
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Reaction of cyclohexylamine with acetaldehyde forming an imine. Sodium sulfate removes water Organic Syntheses, Coll. Vol. 6, p.901 (1988); Vol.
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Triphenylmethyl hexafluorophosphate is a brown powder that hydrolyzes readily to triphenylmethanol. It is used as a catalyst and reagent in organic syntheses.
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Link or the construction of a cyclobutene framework at 700 °C Organic Syntheses, Coll. Vol. 5, p.235 (1973); Vol. 43, p.
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Acetone azine can be used to prepare acetone hydrazone and 2-diazopropane.Organic Syntheses, Coll. Vol. 6, p.392 (1988); Vol. 50, p.
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Many template reactions are only stoichiometric, and the decomplexation of the "templating ion" can be difficult. The alkali metal-templated syntheses of crown ether syntheses are notable exceptions. Metal Phthalocyanines are generated by metal-templated condensations of phthalonitriles, but the liberation of metal-free phthalocyanine is difficult. Some so-called template reactions proceed similarly in the absence of the templating ion.
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"Glyoxal Bisulfite", Organic Syntheses, Collected Volume 3, p.438 (1955). Selenious acid is a key component of the Mecke reagent used for drug checking.
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A convenient synthesis involves flash pyrolysis of certain oximes. In contrast to earlier syntheses, this method avoids the use of highly explosive metal fulminates.
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The European Pharmacopoeia, 2002. fourth ed., Council of Europe, Strasbourg. However, it plays a role in 44% of syntheses in the United States pharmacopoeia.
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Aniline, a benzene ring with an amine group, is a versatile chemical used in many organic syntheses. The genus Helogale (dwarf mongooses) contains two species.
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Some syntheses are feasible on a research or academic level, but not for industry level production. This may lead to further modification of the process.
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The enzyme products of genes AdWS4, TaWS4, GgWS1, GgWS2, GgWS4, and GgDGAT1 sequences have been shown to catalyze wax ester syntheses in several bird species.
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1 (2005). (Article ) # Marshall, J. A.; Yanik, M. M.; Adams, N. D.; Ellis, K. C.; Chobanian, H. R. Organic Syntheses, Vol. 81, p. 157 (2005).
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In order to highlight the remarkable synthetic utility of cascade reactions, the majority of the examples below come from the total syntheses of complex molecules.
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Other solid-phase indole syntheses were also reported, some of which use different scaffolds and metal catalysts to drive the reaction to completion. There are also a variety of other reactions that result in the same indole skeleton. In a review article, Taber et al. categorize these reactions into nine basic types of indole syntheses: Fischer, Mori, Hemetsberger, Buchwald, Sundberg, Madelung, Nenitzescu, van Leusen and Kanematsu.
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Marvel's early research was in classical organic chemistry. He was an enthusiastic contributor to Organic Syntheses. Approximately 20% of the 264 preparations in Collective Volume I of Organic Syntheses were either written or checked by Marvel. Marvel worked with a wide variety of compounds, including dialkyl mercury, hexa-substituted ethanes, dienynes, alkyl lithium and Grignard reagents, quaternary phosphonium, and ammonium compounds, preparing them and investigating their reactions.
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A number of chemical syntheses of bicalutamide have been published in the literature. The procedure of the first published synthesis of bicalutamide can be seen below.
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Figure 2: The general organic chemistry synthetic pathway for mandelonitrile.Corson, B. B.; Dodge, R. A.; Harris, S. A.; Yeaw, J. S. (1941). "Mandelic Acid". Organic Syntheses.
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This reaction type is often used with ketones leading to enones. An example is acetylcyclohexanone elimination with benzeneselenylchloride and sodium hydride.Organic Syntheses Coll. Vol. 6, p.
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Tetramethylthiourea is a commercially available organic compound used in organic syntheses. The core of the compound is thiourea, with each nitrogen connected to two methyl groups.
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Professor Bonnichsen was known nationally and internationally for his interdisciplinary research projects, for overview syntheses of the field, and as a spokesperson for First American studies.
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"Pilot Plant Syntheses - Perfluoro-n-heptane, perfluorodimethylcyclohexane, and high boiling fluorocarbon oils." Ind. Eng. Chem. 39: 319–329. . and on an industrial scale by Du Pont.
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Nonactin is commercially available; as of 2006, these bacterial species produce nonactin: Streptomyces tsukubaensis, Streptomyces griseus, Streptomyces chrysomallus and Streptomyces werraensis. Total syntheses have been reported.
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DAST is prepared by the reaction of diethylaminotrimethylsilane and sulfur tetrafluoride:W. J. Middleton, E. M. Bingham "Diethylaminosulfur Trifluoride" Organic Syntheses, Coll. Vol. 6, p.440; Vol.
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Brown was awarded the Nobel prize in Chemistry in 1979 for this work.Brown, H. C. Organic Syntheses via Boranes John Wiley & Sons, Inc. New York: 1975. .
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The total synthesis of callystatin A has been reported by various groups since its discovery in 1997. These total syntheses vary in their approaches and strategies.
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Adams, R. D.; Barnard, T. S.; Cortopassi, J. E.; Wu, W.; Li, Z. "Platinum-ruthenium carbonyl cluster complexes" Inorganic Syntheses 1998, volume 32, pp. 280-284.
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Generating acylphosphines in this manner is considered a much milder route than other current strategies that require multi-step syntheses involving toxic, volatile and pyrophoric reagents.
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Strictamine is an alkaloid isolated from Alstonia scholaris. Because of its unusual chemical structure, it has attracted research interest and several laboratory syntheses have been reported.
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Calvin A. Buehler and Donald E. Pearson. John Wiley & Sons, 1970. , .Survey of Organic Syntheses, Volume II. Calvin A. Buehler, Donald E. Pearson and Paul F. Hudrlik.
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Diazo compounds can be obtained in an elimination reaction of N-alkyl-N-nitroso compounds,Example: Organic Syntheses, Coll. Vol. 6, p.981 (1988); Vol. 57, p.
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A chemical database is a database specifically designed to store chemical information. This information is about chemical and crystal structures, spectra, reactions and syntheses, and thermophysical data.
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Many free radical-based syntheses show large kinetic solvent effects that can reduce the rate of reaction and cause a planned reaction to follow an unwanted pathway.
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Grandisol was first isolated, identified, and synthesized by J. Tumlinson et al. at Mississippi State University in 1969. The most recent and highest yielding synthetic route to grandisol was reported in January 2010 by a group of chemists at Furman University. Though enantioselective syntheses have been reported, racemic grandisol has proven equally effective at attracting boll weevils as the natural enantiomer, rendering moot the need for enantioselective syntheses for agricultural purposes.
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The next total syntheses were not reported until the late 1980s, using similar methods, namely by using an intermediate available by degradated strychnine. All of these syntheses used harsh conditions. The Overman synthesis sidesteps these problems, and is the first asymmetric total synthesis of strychnine, taking advantage of the diastereoselectivity and mild reaction conditions of the aza-Cope/Mannich reaction. The aza-Cope/Mannich reaction step proceeded in near quantitative yield.
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She is known for working with highly energetic nitrogenous and fluoridated compounds, and created syntheses for a variety of widely used rocket propellant oxidizers. Shreeve's work includes novel syntheses of chlorodifluoroamine and dinitrogen difluoride, precursors to rocket propellant oxidizers that were difficult to synthesize in usable quantities prior to her work. She is also recognized for her synthesis of fluorinated alkyl sulfoxides by controlled hydrolysis of bis(perfluoroalkyl) sulfur dioxides.
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Indium triethyl can be obtained by reacting an ether solution of indium(III) chloride with ethyl magnesium chloride. : + 3 → In(C2H5)3 \+ 3 Other syntheses are also known.
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The reaction is a good alternative to the decomposition of α-diazoketones.Handbook of Reagents for Organic Syntheses, Sulfur-Containing Reagents, ed. L.A. Paquette, Wiley-VCH, 2010, , S. 535.
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Hourdou M.L., Besson F., Tenoux I. & Michel G., 1989. Fatty acid and beta-amino acid syntheses in strains of Bacillus subtilis producing iturinic antibiotics. Lipids, 24, 940-944.
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In the 1980s it was found that dirhodium catalysts provide single cyclopropane isomers in high yields. Applications are found in medicine (drug syntheses) and material science (fullerene derivatives).
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Fischer developed the Fischer oxazole synthesis during his time at Berlin University. The Fischer oxazole synthesis was one of the first syntheses developed to produce 2,5-disubstituted oxazoles.
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As an example camphor tosylhydrazone is synthesised from camphor and tosylhydrazine in ethanol with hydrochloric acid catalysis.2-Bornene, Organic Syntheses, Coll. Vol. 6, p.172 (1988); Vol.
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Danheiser has a particular interest in reproducibility in scientific research. He has been the Editor-in-Chief of the journal Organic Syntheses and a member of the Board of Directors of the Organic Syntheses corporation since 2004. Organic Syntheses has the unusual feature that all data and experiments reported in articles must be confirmed in the laboratory of a member of the editorial board prior to publication. Danheiser has a longstanding interest in laboratory safety and at MIT he has served as the chair of several committees including the MIT Chemistry Department EHS Committee which was recognized in 1991 as the first recipient of the American Chemical Society Division of Chemical Safety national award for "best university safety program".
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The Overman rearrangement may also be used for asymmetric synthesis.Anderson, C. E.; Overman, L. E. J. Am. Chem. Soc. 2003, 125, 12412–12413. ()Asymmetric Overman Rearrangement Organic Syntheses, Vol.
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A disadvantage is that most flux method syntheses produce relatively small crystals. However, some materials such as the "115" heavy fermion superconductors () may grow up to a few centimeters.
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Halogenation of silyl enol ethers gives haloketones. Acyloins form upon organic oxidation with an electrophilic source of oxygen such as an oxaziridine or mCPBA.Organic Syntheses, Coll. Vol. 7, p.
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Gund, T. M.; Thielecke, W.; Schleyer, P. v. R.: Diamantane: PENTACYCLO[7.3.1.14,12.02,7.06,11]TETRADECANE[Butanetetraylnaphthalene, 3,5,1,7-[1,2,3,4]-decahydro-]. In: Organic Syntheses, Band 53, 1973, S. 30, doi:10.15227/orgsyn.053.0030.
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Furstner, A.; Thiel, O. R.; Ackermann, L. (2001). “Exploiting the Reversibility of Olefin Metathesis. Syntheses of Macrocyclic Trisubstituted Alkenes and (R,R)-(−)-Pyrenophorin”. Org. Lett. 3 (3): 449–451. .
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Organic Syntheses is a peer-reviewed scientific journal that was established in 1921. It publishes detailed and checked procedures for the synthesis of organic compounds. A unique feature of the review process is that all of the data and experiments reported in an article must be successfully repeated in the laboratory of a member of the editorial board as a check for reproducibility prior to publication. The journal is published by Organic Syntheses, Inc.
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Aided by Greek mathematics and Islamic mathematics, he discovered the syntheses for hydrochloric acid, nitric acid, distillation and crystallization (the latter two being essential for the understanding of modern mineralogy).
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Recent studies have confirmed (+)-totarol's unique antimicrobial and therapeutic properties. Consequently, (+)-totarol is a promising candidate for a new source of drugs and has been the goal of numerous syntheses.
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Cobalt(II) cyanide has been used as a precursor to cobalt carbonyl.Heinz W. Sternberg, Irving Wender, Milton Orchin Cobalt Tetracarbonyl Hydride: (Cobalt Hydrocarbonyl) Inorganic Syntheses, 1957, vol. V, p. 192.
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A procedural patent was filed on Christmas Eve 1912 relating to these syntheses, which mentioned MDMA without name as a chemical intermediate. He was killed in the First World War.
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At one time CarbolabsREACTION OF SULFOXIDES WITH DIETHYLAMINOSULFUR TRIFLUORIDE: FLUOROMETHYL PHENYL SULFONE, A REAGENT FOR THE SYNTHESIS OF FLUOROALKENES, Organic Syntheses, Coll. Vol. 9, p.446 (1998); Vol. 72, p.
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By including quantum tunnelling, the astrochemical syntheses of various molecules in interstellar clouds can be explained such as the synthesis of molecular hydrogen, water (ice) and the prebiotic important formaldehyde.
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Cephapirin synthesis: In one of the syntheses, 7-aminocephalosporanic acid (7-ACA) is reacted with bromoacetyl chloride to give the amide. The halo group is then displaced by 4-thiopyridine.
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By oxidation of the methyl groups with potassium permanganate collidinic acid is obtained. 2,4,6-Trimethylpyridine is used in organic syntheses (for example, for dehydrohalogenation), by binding the formed hydrogen halides.
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It has been prepared from 3-nitrobenzaldehyde in a sequence of nitro group reduction, diazotization of the amine, and hydrolysis.m-HYDROXYBENZALDEHYDE, Organic Syntheses, Coll. Vol. 3, p.453 (1955); Vol.
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Green Chemistry Letters and Reviews (print: , online: ) is a peer-reviewed scientific journal published quarterly by Taylor & Francis. It publishes full papers and review articles on new syntheses and green chemistry.
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B. I. Zapadinskii, B. I. Liogon'kii, and A. A. Berlin (1973), Syntheses of Tetracarboxylic Acids. Russian Chemical Reviews, volume 42 issue 11, page 939. Online version accessed on 2010-01-03.
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Chemical syntheses of CPA have been published. The following is one such synthesis: Partial synthesis of CPA, using hydroxyprogesterone acetate as a starting material, by Wiechert & Neumann (1965) and Wiechert (1966).
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An example is the reaction of cyclopentadiene with benzylamine to an aza norbornene.N-benzyl-2-azanorbornene Paul A. Grieco and Scott D. Larsen Organic Syntheses, Coll. Vol. 8, p.31; Vol.
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A well exploited member of the [n.n]paracyclophane family is [2.2]paracyclophane. One method for its preparation is by a 1,6-Hofmann elimination:Organic Syntheses, Coll. Vol. 5, p.883 (1973); Vol.
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Olivetol, also known as 5-pentylresorcinol or 5-pentyl-1,3-benzenediol, is an organic compound found in certain species of lichen; it is also a precursor in various syntheses of tetrahydrocannabinol.
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The product of this step is reacted with phenyl isocyanate and subsequently transformed to the 4-Phenylurazol. Cyclization and subsequent oxidation yields PTAD (6). Also Organic Syntheses, Coll. Vol. 6, p.
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René Roy completed his Ph.D. in carbohydrate chemistry from Université de Montréal in 1980, with Stephen Hanessian, developing synthetic methodologies and the syntheses of natural compounds using carbohydrate precursors (Chiron approach).
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Acidification of the resulting salicylate salt gives salicylic acid. :400px Many detailed procedures are described in the journal Organic Syntheses. Carboxylation catalysts include N-Heterocyclic carbenes and catalysts based on silver.
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Work proceeded with focus on enantioselective total syntheses, e.g., on atroposelective syntheses of axially chiral biaryl polyphenols, with recent further important work including controlled assembly of a variety of polyphenols according to integrated strategies, such as in syntheses of extended series of procyanidins (oligomeric catechins) by various groups and of resveratrol polyphenols by the Snyder group at Columbia that included the diverse carasiphenols B and C, ampelopsins G and H, and nepalensinol B. A biomimetic synthesis, and the first formal total synthesis 5-O-Desgalloyl-epi-punicacortein A, a further ellagitannin in its C-glucosyl (C-glucoside subclass), has also recently been accomplished. The novel strategies and methods referred to in these recent examples helped to open the field of polyphenol chemical synthesis to an unprecedented degree.
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A Curtin–Hammett scenario was invoked to explain selectivity in the syntheses of kapakahines B and F, two cyclic peptides isolated from marine sponges. The structure of each of the two compounds contains a twisted 16-membered macrocycle. A key step in the syntheses is selective amide bond formation to produce the correct macrocycle. In Phil Baran’s enantioselective synthesis of kapakahines B and F, macrocycle formation was proposed to occur via two isomers of the substrate.
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Sulfuryl chloride fluoride is the solvent of choice for many reactions that deal with extreme oxidants. For example, it can be used to generate and study free carbocationsMercier HP, Moran MD, Schrobilgen GJ, Steinberg C, Suontamo RJ. The syntheses of carbocations by use of the noble-gas oxidant, : the syntheses and characterization of the (X = Cl, Br, ) and cations and theoretical studies of and (X = F, Cl, Br, I, ). J Am Chem Soc. 2004 May 5;126(17):5533-48.
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Glutamate synthase catalyzes the conversion of 2-oxoglutarate into L-glutamate with L-glutamine serving as the nitrogen source for the reaction. All glutamate syntheses are iron-sulfur flavoproteins containing an iron-sulfur cluster and FMN. The three classes of glutamate syntheses are categorized based on their sequences and biochemical properties. Even though there are three classes of this enzyme, it is believed that they all operate through the same mechanism, only differing by what first reduces the FMN.
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Galantamine is produced from natural resources, but also has many industrial syntheses. Companies such as Janssen, Ortho-McNeil Pharmaceutical, Sanochemia Pharmazeutika, Shire, and Takeda Pharmaceutical Company have industrial processes for synthesizing Galantamine.
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In organic syntheses, such as acid catalyzed reactions, the hydronium ion () can be used interchangeably with the ion; choosing one over the other has no significant effect on the mechanism of reaction.
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Dumitrescu also initiated and coordinated several syntheses of literary history for the institute she led. Aurel Sasu (ed.), Dicționarul biografic al literaturii române, vol. I, p. 539. Pitești: Editura Paralela 45, 2004.
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In 2006, the Association of Canadian Archivists established the Hugh A. Taylor Prize, presented to the writer of the Archivaria article that presents new ideas or syntheses in new and imaginative ways.
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The Overman rearrangement is a chemical reaction that can be described as a Claisen rearrangement of allylic alcohols to give allylic trichloroacetamides through an imidate intermediate.Organic Syntheses, Coll. Vol. 6, p.507; Vol.
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Assagioli, R. (1973). The Act of Will. New York: Penguin Books. p.191 All such elaborate syntheses of thought, feeling, and behavior are built upon learnings and abilities that must eventually operate unconsciously.
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Thymidine diphosphate glucose (often abbreviated dTDP-glucose or TDP-glucose) is a nucleotide-linked sugar consisting of deoxythymidine diphosphate linked to glucose. It is the starting compound for the syntheses of many deoxysugars.
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An example of an electrophilic substitution using a diazomethyl compound is that of a reaction between an acyl halide and diazomethane,Example Organic Syntheses, Coll. Vol. 3, p.119 (1955); Vol. 26, p.
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It is also useful as an intermediate in the recovery of platinum from wastes.George B. Kauffman, Larry A. Teter "Recovery of Platinum from Laboratory Residues" Inorganic Syntheses, 1963, volume 7, pp. 232-236.
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Most large-scale commercial processes rely on the former while some fine chemical syntheses rely on the homogeneous catalysts. Catalysts are based on transition metals such as W, Mo, Re, Ru, and Ti.
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Ester pyrolysis in organic chemistry is a vacuum pyrolysis reaction converting esters containing a β-hydrogen atom into the corresponding carboxylic acid and the alkene. The reaction is an Ei elimination and operates in a syn fashion. Examples include the synthesis of acrylic acid from ethyl acrylate at 590 °C,Organic Syntheses, Coll. Vol. 3, p.30 (1955); Vol. 29, p.2 (1949). Link the synthesis of 1,4-pentadiene from 1,5-pentanediol diacetate at 575 °C Organic Syntheses, Coll. Vol. 4, p.
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High temperature reduction with H2 gives NbO2: :Nb2O5 \+ H2 → 2 NbO2 \+ H2O Niobium monooxide arises from a comproportionation using an arc-furnace:T. B. Reed, E. R. Pollard "Niobium Monoxide" Inorganic Syntheses, 1995 Volume 30, pp. 108–110, 2007. :Nb2O5 \+ 3Nb → 5 NbO The burgundy-coloured niobium(III) oxide, one of the first superconducting oxides, can be prepared again by an comproportionation:Margret J. Geselbracht, Angelica M. Stacy, "Lithium Niobium Oxide: LiNbo2 and Superconducting LiXNbO2" Inorganic Syntheses 1995, Volume 30, Pages: 222–226.
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The synthesis is one of the simplest methods for creating poly-substituted indoles, this procedure has been utilized in numerous natural product syntheses, including aspidophytine, vinblastine, and strychnine Shown below is the fourth step in the synthesis of (+)-Vinblastine, the application of the Fukuyama Indole synthesis to create a disubstituted indole. Sample Fukuyama Indole Reaction Step in the Synthesis of Vinblastine In addition, the fukuyama reaction plays a role in the syntheses of indolocarbazoles, biindolyls, and the total synthesis of vincadifformine and tabersonine.
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Due to the structural complexity, total synthesis has proved difficult, with only a few total syntheses reported so far. Total syntheses have been published for bryostatins 1, 2, 3, 7, 9 and 16. Among them, Wender’s total synthesis of bryostatin 1 is the shortest synthesis of any bryostatin reported, to date. A number of structurally simpler synthetic analogs also have been prepared which exhibit similar biological profile and in some cases greater potency, which may provide a practical supply for clinical use.
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The related Willgerodt–Kindler reaction takes place with elemental sulfur and an amine like morpholine. The initial product is a thioacetamide for example that of acetophenoneOrganic Syntheses, Coll. Vol. 9, p.99 (1998); Vol.
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The Mukaiyama hydration or variants thereof have been featured in the syntheses of (±)-garsubellin A, stigmalone, vinblastine, (±)-cortistatin A, (±)-lahadinine B, ouabagenin, pectenotoxin-2, (±)-indoxamycin B, trichodermatide A, (+)-omphadiol and many more natural products.
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As taxodone readily decomposes into taxodione this synthesis of taxodone also constitutes a formal synthesis of taxodione as well. 400px Since the synthesis of taxodone there have been additional syntheses of taxodione and analogs.
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Other completed total syntheses include natural products (+)-Naseseazines A and B, (+)-Salvileucalin B,, (+)-Psiguadial B and (+)-Pleuromutilin. The group's reaction methodology work has focused primarily on nickel catalysis, cycloadditions, and opening of strained-ring precursors.
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While today a typical synthetic route routinely involves such a procedure, Woodward was a pioneer in showing how, with exhaustive and rational planning, one could conduct reactions that were stereoselective. Many of his syntheses involved forcing a molecule into a certain configuration by installing rigid structural elements in it, another tactic that has become standard today. In this regard, especially his syntheses of reserpine and strychnine were landmarks. During World War II, Woodward was an advisor to the War Production Board on the penicillin project.
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Over the three decades after the discovery of erythromycin A and its activity as an antimicrobial, many attempts were made to synthesize it in the laboratory. The presence of 10 stereogenic carbons and several points of distinct substitution has made the total synthesis of erythromycin A a formidable task. Complete syntheses of erythromycins’ related structures and precursors such as 6-deoxyerythronolide B have been accomplished, giving way to possible syntheses of different erythromycins and other macrolide antimicrobials. Woodward successfully completed the synthesis of erythromycin A.
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There are many laboratory syntheses of uracil available. The first reaction is the simplest of the syntheses, by adding water to cytosine to produce uracil and ammonia: :C4H5N3O + H2O → C4H4N2O2 \+ NH3 The most common way to synthesize uracil is by the condensation of malic acid with urea in fuming sulfuric acid: :C4H4O4 \+ NH2CONH2 → C4H4N2O2 \+ 2 H2O + CO Uracil can also be synthesized by a double decomposition of thiouracil in aqueous chloroacetic acid. Photodehydrogenation of 5,6-diuracil, which is synthesized by beta-alanine reacting with urea, produces uracil.
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One example is (η6-acenaphthene)Mn(CO)3]+.S. B. Kim, S. Lotz, S. Sun, Y. K. Chung, R. D. Pike, D. A. Sweigart "Manganese Tricarbonyl Transfer (MTT) Agents" Inorganic Syntheses, 2010, Vol. 35, 109–128.
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Painting in Space ("Les Peintures dans l`espace" in French) is an art movement that was invented by Yervand Kochar in the 1930s in Paris. This movement syntheses all the possibilities of painting, graphic and sculpture.
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Scheme 3. The first total synthesis of (±)-totarol (+)-Totarol has been the subject of numerous syntheses. The first total synthesis of totarol (Scheme 3)Barltrop, J. A.; Rogers, N. A. J. Chem. Soc. 1958, 2566-2572.
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One of the earliest syntheses of candicine is that of Barger, who made candicine iodide by the N-methylation of hordenine, using methyl iodide.G. Barger (1909). "Synthesis of hordenine, the alkaloid from barley." J. Chem. Soc.
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This is the largest division of the Society. It marked its 100th Anniversary in 2008. The first Chair of the Division was Edward Curtis Franklin. The Organic Division played a part in establishing Organic Syntheses, Inc.
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PBr3 is prepared by treating red phosphorus with bromine. An excess of phosphorus is used in order to prevent formation of PBr5:J. F. Gay, R. N. Maxson "Phosphorus(III) Bromide" Inorganic Syntheses, 1947, vol. 2, 147ff.
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The Strecker synthesis of amino acids involves the reaction of potassium cyanide, ammonium chloride, and an aldehyde to make an alpha amino acid.Kendall, E. C.; McKenzie, B. F. Organic Syntheses, Coll. Vol. 1, p.21 (1941); Vol.
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4-Cyano-3-(trifluoromethyl)aniline, also known as 4-amino-2-(trifluoromethyl)benzonitrile, is a cyanated and trifluoromethylated derivative of aniline. It is the starting material in one of the chemical syntheses of the nonsteroidal antiandrogen bicalutamide.
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Suberic acid, also octanedioic acid, is a dicarboxylic acid, with formula C8H14O4. It is a colorless crystalline solid used in drug syntheses and plastics manufacture. Its name is derived from the Latin word suber which means cork.
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The first total chemical synthesis of cyclophellitol was demonstrated by Tatsuta et al.Tatsuta, K. et al. (1991) ‘Syntheses and Enzyme Inhibiting Activities of Cyclophellitol Analogs’, Journal of Antibiotics. Japan Antibiotics Research Association, 44(8), pp. 912–914.
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Solutions of Cr(II) are used as specialized reducing agents of value in organic synthesis.A. Zurqiyah and C. E. Castro "Reduction of Conjugated Alkenes With Chromium(II) Sulfate: Diethyl Succinate" Organic Syntheses, Vol. 49, p.98 (1969).
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Most notably he patented the process of methanol conversion to gasoline using polyphosphoric acid (PPA) as a catalyst.Donald E. Pearson, Process for preparing hydrocarbons from methanol and phosphorus pentoxide, Patentnumber: 4133838, 1975 This, known as the Pearson process, is currently in use in New Zealand. With post doctoral colleague Sidhaghatta D. Venkataramu he developed a method of spin-label tagging of compounds so they can be traced in biologic systems as well as in industrial applications. During the writing of Survey of Organic Syntheses,Survey of Organic Syntheses.
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Spirotryprostatin B is an indolic alkaloid found in the Aspergillus fumigatus fungus that belongs to a class of naturally occurring 2,5-diketopiperazines. Spirotryprostatin B and several other indolic alkaloids (including Spirotryprostatin A, as well as other tryprostatins and cyclotryprostatins) have been found to have anti-mitotic properties, and as such they have become of great interest as anti-cancer drugs. Because of this, the total syntheses of these compounds is a major pursuit of organic chemists, and a number of different syntheses have been published in the chemical literature.
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MBH reactions are widely used in organic synthesis. For example, this reaction was used to construct key cyclic intermediates for syntheses of salinosporamide A, diversonol, and anatoxin-a.J. Am. Chem. Soc. 2004, 126, 6230-6231.Angew. Chem. Int.
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Because of its potent biological activities, kendomycin has attracted interest as a target of total synthesis. The first total synthesis of kendomycin was accomplished by Lee and Yuan in 2004. The total number of syntheses stands at 6.
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One of the earliest syntheses of DMPEA (then referred to as "homoveratrylamine") was that of Pictet and Finkelstein, who made it in a multi-step sequence starting from vanillin.A. Pictet and M. Finkelstein (1909). "Synthese des Laudanosins." Ber.
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The term total synthesis is less frequently but still accurately applied to the synthesis of natural polypeptides and polynucleotides. For instance, the peptide hormones oxytocin and vasopressin were isolated and their total syntheses were first reported in 1954.
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Esters are widespread in nature and are widely used in industry. In nature, fats are in general triesters derived from glycerol and fatty acids.Isolation of triglyceride from nutmeg: G. D. Beal "Trimyristen" Organic Syntheses, Coll. Vol. 1, p.
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Benzenehexol, also called hexahydroxybenzene, is an organic compound with formula C6H6O6 or C6(OH)6. It is a six-fold phenol of benzene. A. J. Fatiadi and W. F. Sager (1973), Hexahydroxybenzene [Benzenehexol] Organic Syntheses, Coll. Vol. 5, p.
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Cheng, The Logic of Chemical Synthesis, Wiley, New York, 1995, . Regarded by many as one of the greatest living chemists, he has developed numerous synthetic reagents, methodologies and total syntheses and has advanced the science of organic synthesis considerably.
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The acid can be obtained by from dioxalylsuccinate. B. I. Zapadinskii, B. I. Liogon'kii, and A. A. Berlin (1973), Syntheses of Tetracarboxylic Acids. Russian Chemical Reviews, volume 42 issue 11, page 939. Online version accessed on 2010-01-03.
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Aurore Loudet and Kevin Burgess (2007): "BODIPY dyes and their derivatives: Syntheses and spectroscopic properties". Chemical Reviews, volume 107, issue 11, pages 4891–4932. BODIPY dyes are relatively chemically inert. Fluorescence is quenched in a solution, which limits application.
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These substrates may not be convertible to the acyl chlorides.Andrew G. Myers, Bryant H. Yang, and Hou Chen TRANSFORMATION OF PSEUDOEPHEDRINE AMIDES INTO HIGHLY ENANTIOMERICALLY ENRICHED ALDEHYDES, ALCOHOLS, AND KETONES Organic Syntheses, Vol. 77, p. 29 (2000); Coll. Vol.
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Cyclodextrin nanosponges were not discovered to have potential in being drug carriers until work done by Trotta and colleagues. They performed syntheses of new kinds of cyclodextrin nanosponges that revealed many potential applications that had not been previously considered.
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In the example below the (S)-aldehyde reacts with a thiazole to form the (S,S) diastereomer but only a small amount of the (S,R) diastereomer:Organic Syntheses, Coll. Vol. 10, p.140 (2004); Vol. 77, p.78 (2000).
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While monodentate phosphine ligands such as triphenylphosphine and tricyclohexylphosphine are most common, bidentate phosphine ligands can also be useful in organoruthenium compounds. BINAP, in particular, is a useful asymmetric ligand for many asymmetric ruthenium catalysts.Example: Organic Syntheses, Coll. Vol. 10, p.
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This same mechanism occurs to a minor extent in the acetoacetate ester systems, and had previously been detected radiochemically by Harbuck and Rapoport. Most of the above-described syntheses have application in the synthesis of porphyrins, bile pigments, and dipyrrins.
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Dibutylboron trifluoromethanesulfonate (also called dibutylboron triflate or DBBT) is a reagent in organic chemistry. Its chemical formula is C9H18BF3O3S. It is used in asymmetric synthesis for example in the formation of boron enolates in the aldol reaction.Organic Syntheses, Coll. Vol.
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A common reagent for this purpose is thallium(III) trifluoroacetate. The intermediate arylthallium bisfluoroacetate can be isolated and converted to an aryl halide, aryl cyanide, aryl thiol or nitroarene. An example is the iodination of para- xylene.Organic Syntheses, Coll. Vol.
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However, he then argues the question of an essence of both substance and phenomenon emerges as the Essential Stage, which syntheses of the previous two stages. The process is then reiterated with a similar cycle repeated at a higher level.
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N. S. Gill, F.. B. Taylor Inorganic Syntheses 1967, volume 9, page 136-142. FeBr2 reacts with bromide and bromine to form the intensely colored, mixed-valence species [FeBr3Br9]−.Holleman, A. F.; Wiberg, E. "Inorganic Chemistry" Academic Press: San Diego, 2001.
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Triethylindium can be prepared in a similar fashion but with the grignard reagent EtMgBr.Main Group compounds in Inorganic Syntheses, vol 31, By Schultz, Neumayer, Marks; Ed., Alan H. Cowley, John Wiley & Sons, Inc., 1997, :{InCl3} + 3LiMe -> {Me3In.OEt2} + 3LiCl :{InCl3} + 3MeMgI -> {Me3In.
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Anthrone can be prepared from anthraquinone by reduction with tin or copper. An alternative synthesis involves cyclization of o-benzylbenzoic acid induced with hydrogen fluoride. Anthrone syntheses Anthrone condenses with glyoxal to give, following dehydrogenation, acedianthrone, a useful octacyclic pigment.
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In chemistry, chemists might look for elegance in theory, method, technique and procedure. For example, elegance might comprise creative parsimony and versatility in the utilization of resources, in the manipulation of materials, and in the effectiveness in syntheses and analysis.
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Based on this mechanism and working off the pyrrole syntheses of Piloty, the couple provided a method for synthesizing tetraphenylpyrrole . The Piloty-Robinson Pyrrole Synthesis is named in their honor.Olson, J.A.; Shea, K.M. Acc. Chem. Res., 2011, 44(5), 311–321.
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The main method for preparing these compounds is thermolysis of mixtures of phosphorus and sulfur. The product distributions can be analyzed by 31P NMR spectroscopy. More selective syntheses entail (i) desulfurization, e.g. using triphenylphosphine and, complementarily, (ii) sulfidation using triphenylarsine sulfide.
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Two laboratory syntheses of allixin have been developed. In the first method, reported in 1997, allixin was synthesized in 22 steps starting from D-mannose. A shorter synthesis was developed in 1998 which involved only 5 steps, starting from 5-methylfurfural.
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Chemical syntheses of CMA have been published.Langbein, G., Menzer, E., Meyer, M., & Wesemann, R. (1973). New Synthesis of 17alpha Acetoxy-6-Chloro-6-Dehydroprogesterone (Chlormadinone) on 3, 5, 6, 7-Tetrasubstituted Intermediates. Journal Fur Praktische Chemie, 315(1), 8-22.
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Conversely, some syntheses entail nucleophilic displacement of phosphide anion equivalents ("R2P−") by aryl- and alkyl halides. Primary (RPH2) and secondary phosphines (RRPH and R2PH) add to alkenes in presence of a strong base (e.g., KOH in DMSO). Markovnikov's rules apply.
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Sulfonyl bromides have the general formula RSO2Br. In contrast to sulfonyl chlorides, sulfonyl bromides readily undergo light- induced homolysis affording sulfonyl radicals, which can add to alkenes, as illustrated by the use of bromomethanesulfonyl bromide, BrCH2SO2Br in Ramberg–Bäcklund reaction syntheses.
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The final step is a dehydration, as seen following an aldol condensation. It was discovered by the German chemist Hans von Pechmann . With simple phenols, the conditions are harsh, although yields may still be good.Eugene H. Woodruff , Organic Syntheses, Coll. Vol.
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The two syntheses are intricately intertwined chemically, yet they differ basically in the way the central macrocylic corrin ligand system is constructed. Both strategies are patterned after two model corrin syntheses developed at ETH. The first, published in 1964, achieved the construction of the corrin chromophore by combining an A-D-component with a B-C-component via iminoester/enamine-C,C-condensations, the final corrin-ring closure being attained between rings A and B. The second model synthesis, published 1969, explored a novel photochemical cycloisomerization process to create the direct A/D-ring junction as final corrin-ring closure between rings A and D. The A/B approach to the cobyric acid syntheses was collaboratively pursued and accomplished in 1972 at Harvard. It combined a bicyclic Harvard A-D-component with an ETH B-C-component, and closed the macrocyclic corrin ring between rings A and B. The A/D approach to the synthesis, accomplished at ETH and finished at the same time as the A/B approach also in 1972, successively adds rings D and A to the B-C-component of the A/B approach and attains the corrin ring closure between rings A and D. The paths of the two syntheses met in a common corrinoid intermediate.
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As activated NF-κB is associated with oxidative stress, inhibition of the nuclear factor by curcumin is consistent with the chemical's role as an antioxidant. A homologous system to NF-κB signaling exists in plants, evidence that curcumin may play a similar role in C. longa as it does in humans. Curcumin syntheses in C. longa have been until recently, the only readily available synthesis method of curcumin. Today, laboratory syntheses are capable of producing the chemical, and numerous teams are constructing curcumin analogues designed to target specific biological processes, such as the NFκB signaling pathway previously discussed.
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Although the nuclearity of binary metal carbonyl clusters is usually six or fewer, carbido clusters often have higher nuclearities. Metal carbonyls of the iron and cobalt triads are well known to form carbido derivatives. Examples include [Rh6C(CO)15]2−S. Martinengo, D. Strumolo, P. Chini, "Dipotassium μ6-Carbido- Nona-μ-Carbonyl-Hexacarbonylhexarhodate(2-) K2[Rh6(CO)6(μ-CO)9-μ-C]" Inorganic Syntheses, 1980, Volume 20, Pages: 212–215, 2007. and [Ru6C(CO)16]2−.Elena Cariati, Claudia Dragonetti, Elena Lucenti, Dominique Roberto, "Tri- and Hexaruthnium Carbonyl Clusters" Inorganic Syntheses, 2004, Volume 35, 210.
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Dimethyl zinc was used for a long time to introduce methyl groups into organic molecules or to synthesize organometallic compounds containing methyl groups. Grignard reagents, (organo-magnesium compounds), which are easier to handle and less flammable replaced organo-zinc compounds in most laboratory syntheses. Due to differences in reactivity (as well as in reaction by- products) between organo-zinc compounds and Grignard reagents, organo-zinc compounds may be preferred in some syntheses. Its high vapor pressure has led to extensive uses in metalorganic chemical vapor deposition (MOCVD) for the preparation of wide band gap II–VI semiconducting films (e.g.
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This is one of the most famous syntheses in the history of organic chemistry. Both chemists won the Nobel prize (Robinson in 1947 and Woodward in 1965). Strychnine has been used as a plot device in the author Agatha Christie's murder mysteries.
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This enzyme belongs to the family of ligases, specifically those forming carbon-nitrogen bonds as acid-D- amino-acid ligases (peptide syntheses). The systematic name of this enzyme class is (R)-4'-phosphopantothenate:L-cysteine ligase. This enzyme is also called phosphopantothenoylcysteine synthetase.
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Archaeological interpretations of Ciudad Blanca are practically nonexistent. Ciudad Blanca is not mentioned in academic syntheses of Honduran archaeology or Begley's 1999 dissertation on the archaeology of the region.Lange, Frederick W. and Doris Z. Stone, eds. (1984) The Archaeology of Lower Central America.
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Oxidations involving selenium dioxide are often carried out with catalytic amounts of the selenium compound and in presence of a sacrificial catalyst or co-oxidant such as hydrogen peroxide. SeO2-based oxidations sometimes afford carbonyl compounds such as ketones,Organic Syntheses Coll. Vol.
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Alkyl-substituted pyridines show widespread uses among multiple fields of applied chemistry, including the polymer and pharmaceutical industries. For example, 2-methylpyridine, 4-methylpyridine and 2-ethyl-5-methylpyridine exhibit widespread use in syntheses of latexes, ion-exchange matrixes, and photography materials.
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Carbomethoxymethylenetriphenylphosphorane is a chemical compound used in organic syntheses. It contains a phosphorus atom bound to three phenyl groups, and doubly bound to the alpha position of methyl acetate. It undergoes a Wittig reaction. It is used in the Vitamin B12 total synthesis.
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Vanadium(III) fluoride is the chemical compound with the formula VF3. This yellow-green, refractory solid is obtained in a two-step procedure from V2O3.Sturm, B. J.; Sheridan, C. W. "Vanadium(III) Fluoride" Inorganic Syntheses 1963; Vol. 7, pages 52-54. .
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Iodine pentafluoride is an interhalogen compound with chemical formula IF5. It is one of the fluorides of iodine. It is a colorless liquid, although impure samples appear yellow. It is used as a fluorination reagent and even a solvent in specialized syntheses.
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Diazo compounds are used as precursors to carbenes, which are generated by thermolysis or photolysis, for example in the Wolff rearrangement. As such they are used in cyclopropanation for example in the reaction of ethyl diazoacetate with styrene.Organic Syntheses, Coll. Vol. 6, p.
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He received the Nichols Medal, the Manufacturing Chemists' Association Award for College Teaching, and the John R. Kuebler Award of Alpha Chi Sigma. He was a member of the editorial boards of Organic Syntheses and the Journal of the American Chemical Society.
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" Journal of Organometallic Chemistry, 1964, 2, 245-250. :(C6F5)3B + Li(C6F5) → [Li(OEt2)3][B(C6F5)4] Since its discovery, many revised syntheses have been described.Martin, Eddy, Hughes, David, and Lancaster, Simon. "The composition and structure of lithium tetrakis(pentafluorophenyl)borate diethyletherate.
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T. A. Montzka, J. D. Matiskella and R. A. Partyka, ; Chem. Abstr. 95, 43442z (1981). Starting material for this preparation is ketoester 1, available by one of the classical benzomorphan syntheses. Condensation with the ylide from Triethyl phosphonoacetate (HWE reaction) affords diester 2.
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Finally, genomics brought together the molecular and microbiological syntheses - in particular, horizontal gene transfer between bacteria shows that prokaryotes can freely share genes. Many of these points had already been made by other researchers such as Ulrich Kutschera and Karl J. Niklas.
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The Reissert indole synthesis is a series of chemical reactions designed to synthesize indole or substituted-indoles (4 and 5) from ortho-nitrotoluene 1 and diethyl oxalate 2.Noland, W. E.; Baude, F. J. Organic Syntheses, Coll. Vol. 5, p. 567 (1973); Vol.
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Symmetrical 1,3,5-triazines are prepared by trimerization of certain nitriles such as cyanogen chloride or cyanimide. Benzoguanamine (with one phenyl and 2 amino substituents) is synthesised from benzonitrile and dicyandiamide.Benzoguanamine J. K. Simons and M. R. Saxton Organic Syntheses Coll. Vol. 4, p.
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Corey, E. J.; Cho, H.; Rücker C.; Hua, D. H. "Studies with trialkylsilyltriflates: new syntheses and applications." Tetrahedron Lett. 1981, 22, 3455–3458. Primary alcohols can be protected in less than one hour while some hindered alcohols may require days of reaction time.
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As one of his thoroughly documented and well written syntheses, let us note his last publication in 1939 "Die pflanzliche Ernährung in Hungerszeiten, auf Grund von eigenen Erfahrungen in Osteuropa". Maurizio's daughter, Anna Maurizio (1900–1993), was an internationally recognised researcher in apiculture.
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R. Bruce King is emeritus Regents Professor at the University of Georgia. He has contributed to many areas of organometallic chemistry, including synthesis, spectroscopy, and theory. He is the author and editor of several monographs and book series.King, R. B. Organometallic Syntheses.
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Methylphosphine is the simplest organophosphorus compound with the formula CH3PH2, often written MePH2. It is a malodorous gas that condenses to a colorless liquid. It can be produced by methylation of phosphide salts:W. L. Jolly “Methylphosphine” Inorganic Syntheses 1968, volume 11, p. 124.
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William S. Wadsworth and William D. Emmons further defined the reaction.Wadsworth, W. S., Jr.; Emmons, W. D. J. Am. Chem. Soc. 1961, 83, 1733. ()Wadsworth, W. S., Jr.; Emmons, W. D. Organic Syntheses, Coll. Vol. 5, p.547 (1973); Vol. 45, p.44 (1965).
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It is a dark brown solid that decomposes with evolution of O2 in water. It dissolves in concentrated nitric acid to give brown solutions containing the Ag2+ ion. Peter Fischer, Martin Jansen "Electrochemical Syntheses of Binary Silver Oxides" 1995, vol. 30, pp. 50–55.
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Canthaxanthin is a keto-carotenoidEfficient Syntheses of the Keto-carotenoids Canthaxanthin, Astaxanthin, and Astacene. Seyoung Choi and Sangho Koo, J. Org. Chem., 2005, 70 (8), pages 3328–3331, pigment widely distributed in nature. Carotenoids belong to a larger class of phytochemicals known as terpenoids.
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DERA used in islatravir biocatalysis. Bonds formed by DERA are highlighted in red. DERA is being used in chemical syntheses as a tool for green, enantioselective aldol reactions. Formation of the deoxyribose skeleton from small molecules can facilitate the synthesis of nucleoside reverse transcriptase inhibitors.
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Several synthetic routes exist to corannulene. Flash vacuum pyrolysis techniques generally have lower chemical yields than solution- chemistry syntheses, but offer routes to more derivatives. Corannulane was first isolated in 1966 by multistep organic synthesis. In 1971, the synthesis and properties of corannulane were reported.
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The compound has uses ranging from medicine to laboratory syntheses of chemically similar compounds. o-Cresophthalein has been used to derive polyamides and polyimides, colorimetrically estimate calcium in serum, and predict amount of time to wait before blood collection after a patient receives gadodiamide.
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Through the use of the Krische allylation, this synthesis was accomplished via a much shorter route than previous syntheses of the molecule. De Brabander synthesis of Psymberin In 2016, Tao employed the Krische allylation to his synthesis of callyspongiolide using the chiral SEGPHOS catalyst complex.
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The compound has been synthesized from D-mannitol. Alternative syntheses were realized through the asymmetric isoprenylation of correspondent aldehyde (prenal) and alcohol (prenol). Chiral resolution of racemic precursor has been found to provide both enantiomers of ipsdienol in high enentiomeric purity and in preparative scale.
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The two 2003 syntheses used very different strategies, with Isobe's route based on a Diels-Alder approach and Du Bois's work using C–H bond activation. Since then, methods have rapidly advanced, with several new strategies for the synthesis of tetrodotoxin having been developed.
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104 (5): 2199-2238. . however, reported syntheses include 45- up to 90- membered macroheterocycles.Cain, M. F.; Forrest, W. P.; Peryshkov, R. V.; Schrock, R. R. Muller, P. (2013). “Synthesis of a TREN in Which the Aryl Substituents are Part of a 45 Atom Macrocycle”.
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Numbering of gelsemine Gelsemine was isolated from G. sempervirens Ait., in 1870. Note, the use of Chen et al. is, in part, for the thorough manner in which it reviews the earlier literature on synthetic efforts toward, and total syntheses of the gelsemine target.
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The Vima Nyingtik itself consists of three sections:Rigpa Shedra (August, 2009). "Vima Nyingtik". Source: (accessed: Saturday October 17, 2009) # tantras (rgyud), which refer to the Seventeen Tantras; # āgamas (lung), which are largely Tibetan syntheses; # upadēśavargas (man ngag); these refer to 119 treatises of pith advice.
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This species is prepared from the nitrogen mustard N(CH2CH2Cl)3.R. Morassi, L. Sacconi "Tetradentate Tripod Ligands Containing Nitrogen, Sulfur, Phosphorus, and Arsenic as Donor Atoms" Inorganic Syntheses 1976, vol. 16 p. 174-180. N,N,N-trimethyltren, N(CH2CH2NHMe)3 is also available.
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Structure of the anion In chemistry, orthosilicate is the anion , or any of its salts and esters. It is one of the silicate anions. It is occasionally called the silicon tetroxide anion or group.C. A. Kumins, and A. E. Gessler (1953), "Short-Cycle Syntheses of Ultramarine Blue".
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Her research interests include bimetallic hydrogenase enzymes containing CO and CN ligands. Darensbourg sits on the board of Inorganic Syntheses, where she also served as the editor-in-chief of volume 32. In 2011, she was elected fellow of the American Academy of Arts and Sciences.
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This is one of many known chemical syntheses. Alkyl groups can also be removed in a process known as dealkylation. Alkylating agents are often classified according to their nucleophilic or electrophilic character. In oil refining contexts, alkylation refers to a particular alkylation of isobutane with olefins.
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Organic Syntheses, volume 36, page 86; Coll. Vol. 4, p.881 (1963) :SnCl4 \+ 4 (C2H5)MgBr → (CH3CH2)4Sn + 4 MgBrCl The same reaction can be used to obtain tetra-n-propyltin and tetra-n-butyltin. Tetraethyltin is converted in the body to the more toxic triethyltin.
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The enantioselective desymmetrisation however delivers a useful product. This particular conversion utilizes the enzyme cholinesterase.Donald R. Deardorff, Colin Q. Windham, and Chris L. Craney "Enantioselective Hydrolysis of cis-3,5-diacetoxycyclopentene: (1R,4S)-(+)-4-Hydroxy-2-cyclopentenyl Acetate" Organic Syntheses, Coll. Vol. 9, p.487 (1998); Vol.
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Syntheses of large complex catalysts are time and resource consuming. An unexpected deviation from the design could be disastrous. Once a catalyst is discovered, modification for further adjustment could be so synthetically challenging that it is easier to study the poor catalyst than to improve it.
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Saxitoxin dihydrochloride is an amorphous hygroscopic solid, but X-ray crystallography of crystalline derivatives enabled the structure of saxitoxin to be determined. Oxidation of saxitoxin generates a highly fluorescent purine derivative which has been utilized to detect its presence. Several total syntheses of saxitoxin have been accomplished.
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Many methods are known for conversion of Nb2O5 to the halides. The main problem is incomplete reaction to give the oxyhalides. In the laboratory, the conversion can be effected with thionyl chloride:D. Brown "Niobium(V) Chloride and Hexachloroniobates(V)" Inorganic Syntheses, 1957 Volume 9, pp. 88–92.
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The book was written with co-author Donald E. Pearson, an organic chemist from Vanderbilt University. The main focus of the text is the synthesis of particular classes of hydrocarbons or functional groups from other functional groups.Survey of Organic Syntheses. Calvin A. Buehler and Donald E. Pearson.
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Capric acid is used in the manufacture of esters for artificial fruit flavors and perfumes. It is also used as an intermediate in chemical syntheses. It is used in organic synthesis and industrially in the manufacture of perfumes, lubricants, greases, rubber, dyes, plastics, food additives and pharmaceuticals.
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Dichloromethyl methyl ether (HCl2COCH3) is an organic compound that belongs to the class of ethers with a dichloromethyl group and a methyl group. It can be synthesized from methyl formate and a mixture of phosphorus pentachloride and phosphorus oxychlorideOrganic Syntheses, Coll. Vol. 5, p.365 (1973); Vol.
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This method, which is largely obsolete, uses sodium in the presence of proton sources. Especially for fine chemical syntheses, lithium aluminium hydride is used to reduce esters to two primary alcohols. The related reagent sodium borohydride is slow in this reaction. DIBAH reduces esters to aldehydes.
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He also developed industrially attractive total syntheses of caffeine and theophylline, starting from urea. In addition to academic textbooks, he wrote 150 experimental works in Poland and abroad. A promoter of sixteen doctoral dissertations, five of Prof. Bobrański's doctoral students later became professors in their own right.
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The tetravalent moiety CO4 is found in stable organic compounds; they are formally esters of orthocarbonic acid, and therefore are called orthocarbonates. For example, tetraethoxymethane can be prepared by the reaction between chloropicrin and sodium ethoxide in ethanol.Orthocarbonic acid, tetraethyl ester Organic Syntheses, Coll. Vol. 4, p.
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No such reconstruction is possible with the Cholula pyramid.Solís, p. 70. Most of the publications that do exist are technical field reports with few syntheses of data gathered. For this reason, it has not played a significant role in the understanding of Mesoamerica as to date.
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Cobalt trifluoride can be prepared in the laboratory by treating with fluorine at 250 °C:H. F. Priest (1950): "Anhydrous Metal Fluorides". In Inorganic Syntheses, McGraw-Hill, volume 3, pages 171-183. : + 3/2 → + In this redox reaction, and are oxidized to and , respectively, while is reduced to .
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Three total syntheses of agaritine have been completed. The first was performed in 1962 by R.B. Kelly et al. (Figure 3). These researchers used as their key step the coupling of the γ-azide of N-carbobenzoxy-L-glutamic acid (9) with α- hydroxy-p-tolylhydrazine (8).
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The salt is synthesized by treating carbon disulfide with sodium cyanide to give the cyanodithioformate salt, which eliminates elemental sulfur in aqueous solution:R. H. Holm, A. Davison "Metal Complexes Derived from cis-1,2-Dicyano-1,2-Ethylenedithiolate and Bis(trifluoromethyl)-1,2-Dithiete" Inorganic Syntheses 1967, volume X, pp.8-26.
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National Toxicology Program"Summary of Data for Chemical Selection" The compound is prepared by acylation of 2-bromopyridine via the Grignard reagent.Trécourt, F.; Breton, G.; Bonnet, V.; Mongin, F.; Marsais, F.; Quéguiner, G., "New Syntheses of Substituted Pyridines via Bromine–Magnesium Exchange", Tetrahedron 2000, volume 56, pp. 1349-1360. .
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Barron's, 2002, p. 109. Well- known examples include the Grignard reaction, the Sabatier reaction, the Wittig reaction, the Claisen condensation, the Friedel-Crafts acylation, and the Diels-Alder reaction. Books have been published devoted exclusively to name reactions;Alfred Hassner, C. Stumer. Organic syntheses based on name reactions.
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DAINV reactions often involve heteroatoms, and can be used to form heterocyclic compounds. This makes the DAINV reaction particularly useful in natural product syntheses, where the target compounds often contain heterocycles. Recently, the DAINV reaction has been used to synthesize a drug transport system which targets prostate cancer.
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R. B. King Organometallic Syntheses. Volume 1 Transition-Metal Compounds; Academic Press: New York, 1965. . For even higher purification efficiencies, a temperature gradient is applied, which also allows for the separation of different fractions. Typical setups use an evacuated glass tube that is heated gradually in a controlled manner.
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The economic engine would be based on renewable resources at this point. Production and consumption methods would adhere to sustainability regulations. These conflict-based syntheses have several potential outcomes. One is that the most powerful economic and political forces will preserve the status quo and bolster their dominance.
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ZrBr4 is prepared by the action of bromine on zirconium oxide via a carbothermic reaction:R. C. Young, Hewitt G. Fletcher, "Anhydrous Zirconium Tetrabromide" Inorganic Syntheses, 1939, vol. 1, pp. 49–51. : ZrO2 \+ 2 C + 2 Br2 → ZrBr4 \+ 2 CO Like many related tetrahalides, it is purified by sublimation.
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15, pp. 222–225. In some cases, salts are produced of anions that cannot be generated in water, such as the tetrahedral [NiCl4]2− salt.Naida S. Gill, F. B. Taylor "Tetrahalo Complexes of Dipositive Metals in the First Transition Series" Inorganic Syntheses, 1967, Vol. 9, pp. 136–142.
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Three syntheses of zolpidem are common. 4-methylacetophenone is used as a common precursor. This is brominated and reacted with 2-amino-5-methylpyridine to give the imidazopyridine. From here the reactions use a variety of reagents to complete the synthesis, either involving thionyl chloride or sodium cyanide.
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Since alkene geometric isomers are also classified as diastereomers, this reaction would also be called diastereoselective. :Stereoselective dehalogenation The addition of formic acid to norbornene is also stereospecific because the exo isomer is formed exclusively without any of the endo isomer:Organic Syntheses Coll. Vol. 5, p.852 (1973); Vol.
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The Russian chemist Nikolai Kischner first prepared cyclobutanone in 1905. He synthesized cyclobutanone in a low yield from cyclobutanecarboxylic acid in several reaction steps. This process is cumbersome and inefficient by today's standards. :Synthesis of cyclobutanone from cyclobutanecarboxylic acid More efficient, high-yielding syntheses have since been developed.
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Phenols undergo esterfication. Phenol esters are active esters, being prone to hydrolysis. Phenols are reactive species toward oxidation. Oxidative cleavage, for instance cleavage of 1,2-dihydroxybenzene to the monomethylester of 2,4 hexadienedioic acid with oxygen, copper chloride in pyridine2,4-Hexadienedioic acid, monomethyl ester, (Z,Z)- Organic Syntheses, Coll. Vol.
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Brucine, an alkaloid closely related to strychnine, is most commonly found in the Strychnos nux-vomica tree. Brucine poisoning is rare, since it is usually ingested with strychnine, and strychnine is more toxic than brucine. In synthetic chemistry, it can be used as a tool for stereospecific chemical syntheses.
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Hydrozirconation is a form of hydrometalation. Substrates for hydrozirconation are alkenes and alkynes. With terminal alkynes the terminal vinyl zirconium product is predominantly formed. Secondary reactions are nucleophilic additions, transmetalations, conjugate additions,Conjugate Addition Of A Vinylzirconium Reagent: 3-(1-Octen-1-Yl)Cyclopentanone, Organic Syntheses, Coll. Vol.
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The idea of an extended evolutionary synthesis is to extend the 20th century modern synthesis to include concepts and mechanisms such as multilevel selection theory, transgenerational epigenetic inheritance, niche construction and evolvability—though several different such syntheses have been proposed, with no agreement on what exactly would be included.
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Keisuke Takahashi et al., "Total Synthesis of (-)-Kaitocephalin Based on a Rh- Catalyzed C-H Amination", Org. Lett. 14 (2012): 1644-1647 To date, nine syntheses have been reported by seven research groups. The first synthesis was performed in 2001 by a team at the University of Tokyo.
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L., McCann, III and T. M. Brown "Tungsten(V) Chloride" Inorganic Syntheses 1972, Volume XIII, pp. 150-154. :2 WCl6 \+ C2Cl4 → W2Cl10 \+ C2Cl6 The blue green solid is volatile under vacuum and slightly soluble in nonpolar solvents. The compound is oxophilic and is highly reactive toward Lewis bases.
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Syntheses of cisplatin start from potassium tetrachloroplatinate. Several procedures are available. One obstacle is the facile formation of Magnus's green salt (MGS), which has the same empirical formula as cisplatin. The traditional way to avoid MGS involves the conversion of K2PtCl4 to K2PtI4, as originally described by Dhara.
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One method for preparing β-phenethylamine, set forth in J. C. Robinson and H. R. Snyder's Organic Syntheses (published 1955), involves the reduction of benzyl cyanide with hydrogen in liquid ammonia, in the presence of a Raney-Nickel catalyst, at a temperature of 130 °C and a pressure of 13.8 MPa. Alternative syntheses are outlined in the footnotes to this preparation. A much more convenient method for the synthesis of β-phenethylamine is the reduction of ω-nitrostyrene by lithium aluminum hydride in ether, whose successful execution was first reported by R. F. Nystrom and W. G. Brown in 1948. Phenethylamine can also be produced via the cathodic reduction of benzyl cyanide in a divided cell.
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An example of a synthetically achieved small ellagitannin, tellimagrandin II, derived biosynthetically and sometimes synthetically by oxidative joining of two of the galloyl moieties of 1,2,3,4,6-pentagalloyl- glucose True polyphenols from the tannin and other WBSSH types are routinely biosynthesized in the natural sources from which they derive; their 'chemical' syntheses (using standard "bench" organic chemical methods) were somewhat limited until the first decade of the new millennium because these syntheses involve challenging regioselectivity and stereoselectivity issues. Early work focused on the achiral synthesis of phenolic-related components of polyphenols in the late 70s,Botha JJ et al. (1978). Direct synthesis, structure and absolute configuration of biflavonoids from black wattle bark (mimosa) extract. J. Chem. Soc. Chem. Commun.
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He was on the editorial board of Inorganic Syntheses and edited Volume 10. He also edited books on boron chemistry and transition-metal hydrides and wrote reviews on complexes with unusual coordination numbers. A tribute to Muetterties has also been published.R. G. Bergman, G. W. Parshall, and K. N. Raymond.
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It is prepared in the laboratory by disproportionation of phosphorous acidGokhale, S. D.; Jolly, W. L., "Phosphine", Inorganic Syntheses 1967, volume 9, pp. 56–58. :4 H3PO3 → PH3 \+ 3 H3PO4 Phosphine evolution occurs at around 200 °C. Alternative methods involve the hydrolysis of aluminium phosphide, calcium phosphide, and tris(trimethylsilyl)phosphine.
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Succinimide is an organic compound with the formula (CH2)2(CO)2NH. This white solid is used in a variety of organic syntheses, as well as in some industrial silver plating processes. The compound is classified as a cyclic imide. It may be prepared by thermal decomposition of ammonium succinate.
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Chloryl fluoride is the chemical compound with the formula ClO2F. It is commonly encountered as side-product in reactions of chlorine fluorides with oxygen sources.Chrisie, K. O.; Wilson, R. D.; Schack, C. J. "Chloryl fluoride" Inorganic Syntheses, 1986, volume 24, pages 3–5. It is the acyl fluoride of chloric acid.
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Diars is prepared by the reaction of ortho-dichlorobenzene and sodium dimethylarsenide:Feltham, R. D.; Silverthorn, W. "o-Phenylenebis(dimethylarsine)" Inorganic Syntheses 1967, Vol. X, pp. 159–164. :CHCl + 2 NaAs(CH) → CH(As(CH)) + 2 NaCl It is a colorless liquid. Oxygen converts diars to the dioxide, CH(As(CH)O).
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In the preparation of EuS, powdered europium(III) oxide (Eu2O3) is treated with hydrogen sulfide (H2S) at 1150 °C. The crude EuS product is purified by heating at 900 °C under vacuum to remove excess sulfur.Archer, R. D. Mitchel, W. N. Inorganic Syntheses, Europium (II) Sulfide. 1967, volume 10, 77-79.
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DOI: 10.1016/S0010-2180(99)00032-2 upright=2 Scott's flash vacuum pyrolysis syntheses of corannulene. Many of the polycyclic aromatic hydrocarbons known to be tumorigenic or mutagenic are found in atmospheric aerosols, which is connected to the thermal rearrangement of polycyclic aromatic hydrocarbons in fast soot formation during combustion.
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His works are eclectic syntheses of disparate elements. Their extremes of contrast, and outrageousness were reflections of his personal life. Kupferman resided in Rhinebeck, New York, where he and his wife Pei-Fen welcomed members of the community. On the day before Thanksgiving, November 26, 2003, he died of heart failure.
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1,2,3,4-Tetraphenylnaphthalene is a polycyclic aromatic hydrocarbon commonly prepared in the undergraduate teaching laboratory as an introduction to the Diels-Alder reaction, in this case between benzyne, which acts as the dienophile, (generated in situ) and tetraphenylcyclopentadienone, which acts as the diene.Organic Syntheses, Coll. Vol. 5, p.1037 (1973); Vol.
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Histrionicotoxins are a class rather than a specific poison and this broad spectrum poses synthetic challenges. Structures of histrionicotoxins were characterized in 1971. Since then, several synthetic studies and total syntheses have been carried out. Table 1 describes some of the many variations in histrionicotoxin alkaloids from the parent molecule (283A).
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4-Nitrobenzaldehyde is an organic aromatic compound containing a nitro group para-substituted to an aldehyde. Nitrobenzyldiacetate is obtained by the reaction of 4-nitrotoluene and chromium(VI) oxide in acetic anhydride. 4-Nitrobenzaldehyde is obtained by hydrolysis by sulfuric acid in ethanol.4-Nitrobenzaldehyd, Versuchsvorschrift aus: Organic Syntheses, Coll. Vol.
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Miller P.S. e.a (1971) "Syntheses and properties of adenine and thymine nucleoside alkyl phosphotriesters, the neutral analogs of dinucleoside monophosphates." Journal of the American Chemical Society. Vol 93, pp. 6657-65 Bucks research group focused on the use of this phosphate methylated DNA, in particular because of its neutral electrical properties.
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1 In another method BINOL is esterified with pentanoyl chloride. The enzyme cholesterol esterase hydrolyses the (S)-diester but not the (R)-diester. The (R)-dipentanoate is hydrolysed in a second step with sodium methoxide."(S)-(−)- and (R)-(+)-1,1′-bi-2-naphthol" , Romas J. Kazlauskas in Organic Syntheses, Coll. Vol.
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The first reported syntheses of ferrocene were nearly simultaneous. Pauson and Kealy synthesised ferrocene using iron(III) chloride and a Grignard reagent, cyclopentadienyl magnesium bromide. Iron(III) chloride is suspended in anhydrous diethyl ether and added to the Grignard reagent. A redox reaction occurs, forming the cyclopentadienyl radical and iron(II) ions.
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The synthesis is reminiscent of the Chichibabin reaction. Some related bulky pyridine compounds have been described, including 2,4,6-tri-t-butylpyridine.Francis V. Scalzi, Norman F. Golob "Alkylation of pyridine with tert-butyllithium. Convenient syntheses of 2,6-di-tert- butylpyridine and 2,4,6-tri-tert-butylpyridine" J. Org. Chem. 1971, vol 36, pp 2541–2542 .
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Important reactions include chlorination giving methanesulfenyl chloride (CH3SCl), methanesulfinyl chloride (CH3S(O)Cl),Irwin B. Douglass and Richard V. Norton "Methanesulfinyl Chloride" Organic Syntheses, Coll. Vol. 5, p.709-712 (1973). and methanesulfonyl chloride (CH3SO2Cl) as well as oxidation with hydrogen peroxide or peracetic acid giving the thiosulfinate methyl methanethiosulfinate (CH3S(O)SCH3).
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1-Hydroxyadamantane is readily formed by hydrolysis of 1-bromadamantane in aqueous solution of acetone. It can also be produced by ozonation of the adamantane:Zvi Cohen, Haim Varkony, Ehud Keinan, and Yehuda Mazur Tertiary alcohols from hydrocarbons by ozonation on silica gel: 1-adamantanol Organic Syntheses, Coll. Vol. 6, p. 43 (1988); Vol.
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Desilylation is the reverse of silylation: the silyl group is exchanged for a proton. Various fluoride salts (e.g. sodium, potassium, tetra-n-butylammonium fluorides) are popular for this purpose.Mercedes Amat, Sabine Hadida, Swargam Sathyanarayana, and Joan Bosch "Regioselective Synthesis of 3-Substituted Indoles: 3-Ethylindole" Organic Syntheses 1997, volume 74, page 248.
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In the wake of the work and various syntheses around this important issue, researchers, and Zaug with McPhee (2000) and other significant contributors have called this line of research in the styling "Constitutive role of communication in organizations" (CCO) (Putnam, Nicotera and McPhee, 2011; Putnam, Nicotera , 2009; Taylor, Van Every, 2000; Taylor, 2011).
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The substance is air sensitive and its synthesis requires air- free techniques. It was first prepared by Hafner and Fischer by the reaction of CrCl3, aluminium, and benzene, in the presence of AlCl3. This so-called reductive Friedel-Crafts method was pioneered by E.O. Fischer and his students.King, R. B. Organometallic Syntheses.
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The acid can be obtained by hydrolysis of tetraethyl ethylenetetracarboxylate, which in turn can be obtained from diethyl dibromomalonate with sodium iodide.B. I. Zapadinskii, B. I. Liogon'kii, and A. A. Berlin (1973), Syntheses of Tetracarboxylic Acids. Russian Chemical Reviews, volume 42 issue 11, page 939. Online version accessed on 2010-01-03.
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The Education Press Association of America has given Sylwester Distinguished Achievement Awards for two of the 18 syntheses of cognitive neuroscience research that he published in Educational Leadership,Educational Leadership Association for Supervision and Curriculum Development and one award for Best Series of Articles in an Educational Journal, published in The Instructor Magazine.
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It can be made from cycloheptatriene (tropylidene) and bromine or phosphorus pentachloride"Tropylium tetrafluorate" Organic Syntheses, Coll. Vol. 5, p.1138 (1973); Vol. 43, p.101 (1963). link It is a planar, cyclic, heptagonal ion; it also has 6 π-electrons (4n + 2, where n = 1), which fulfills Hückel's rule of aromaticity.
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In particular, Rathore was well known for his contributions to studies of the Scholl reaction mechanism, syntheses of cofacially arrayed polyfluorenes, and applications of nitric oxide complexes with aromatic donors. His recent work was focused on elucidating the application of frontier molecular orbitals (FMOs) in the rational design of novel charge-transfer materials.
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One classic in total synthesis is quinine total synthesis, which, before its total synthesis by Robert Burns Woodward and William von Eggers Doering in 1944,Remembering Organic Chemistry Legend Robert Burns Woodward, "C&EN;", 4/10/2017 had a history of many partial syntheses that spanned 150 years and included disputes and frustration.
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Several syntheses of platinum(II) acetate have been reported. For example, G. Wilkinson et al. reported a synthesis which involved dissolving sodium hexahydroxyplatinate in nitric acid, heating with acetic acid, and removing excess nitric acid by reduction with formic acid. However, Wilkinson's group reported great variability in the results of this synthesis.
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There are many ways to synthesize α-phenylcinnamic acid. Some of the more popular methods of formation include the condensation of phenylacetyl chloride with benzaldehyde in the presence of triethylamine, the distillation of benzylmandelic acid, or by the reaction of sodium phenylacetate with benzaldehyde in acetic anhydride.Organic Syntheses, Coll. Vol. 4, p.
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The CBS Reduction has since been utilized by organic chemists as a reliable method for the asymmetric reduction of achiral ketones. Notably, it has found prominent use not only in a number of natural product syntheses, but has been utilized on large scale in industry (See Scope Below). Several reviews have been published.
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This gene encodes a protein that possesses three distinct enzymatic activities, methylenetetrahydrofolate dehydrogenase (1.5.1.5), methenyltetrahydrofolate cyclohydrolase (3.5.4.9) and formate–tetrahydrofolate ligase (6.3.4.3). Each of these activities catalyzes one of three sequential reactions in the interconversion of 1-carbon derivatives of tetrahydrofolate, which are substrates for methionine, thymidylate, and de novo purine syntheses.
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2-Bromopyridine is an organic compound with the formula BrC5H4N. It is a colorless liquid that is used as an intermediate in organic synthesis. It can be prepared from 2-aminopyridine via diazotization followed by bromination.Allen, C. F. H.; Thirtle, John R. "2-Bromopyridine" Organic Syntheses 1946, volume 26, pp. 16-18.
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Wöhler's 1823 synthesis involved reducing sodium tungstate and tungsten trioxide with hydrogen gas at red heat. A more modern approach reduces a melt of the reactants with electricity rather than with hydrogen. Microwave synthesis is also possible, using tungsten powder as the reducing agent. Hydrothermal (both batch and flow) syntheses are also possible.
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Aminoshikimic acid is an unnatural carbohydrate, although aminoshikimic acid is the namesake of the aminoshikimate pathway, which generates the 3-amino-5-hydroxybenzoic acid (AHBA) starter unit required for the biosynthesis of the ansamycins and mitomycins. The first microbe- catalyzed syntheses of aminoshikimic acid were described by Guo and Frost in 2004.
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Due to the high potency and clinical need for cancer treatments, epothilones have been the target of many total syntheses. The first group to publish the total synthesis of epothilones was S. J. Danishefsky et al. in 1996. This total synthesis of epothilone A was achieved via an intramolecular ester enolate- aldehyde condensation.
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During the late 1940s, Woodward synthesized many complex natural products including quinine, cholesterol, cortisone, strychnine, lysergic acid, reserpine, chlorophyll, cephalosporin, and colchicine. With these, Woodward opened up a new era of synthesis, sometimes called the 'Woodwardian era' in which he showed that natural products could be synthesized by careful applications of the principles of physical organic chemistry, and by meticulous planning. Many of Woodward's syntheses were described as spectacular by his colleagues and before he did them, it was thought by some that it would be impossible to create these substances in the lab. Woodward's syntheses were also described as having an element of art in them, and since then, synthetic chemists have always looked for elegance as well as utility in synthesis.
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Reductive colloidal syntheses as such have yielded tetrahedral, cubic, irregular-prismatic, icosahedral, and cubo-octahedral nanoparticles, whose dispersity is also dependent on the concentration ratio of capping agent to precursor, and which may be applicable to catalysis. The precise mechanism of shape-controlled colloidal synthesis is not yet known; however, it is known that the relative growth rate of crystal facets within the growing nanostructure determines its final shape. Polyol syntheses of platinum nanoparticles, in which chloroplatinic acid is reduced to PtCl42− and Pt0 by ethylene glycol, have also been a means to shape-controlled fabrication. Addition of varying amounts of sodium nitrate to these reactions was shown to yield tetrahedra and octahedra at high concentration ratios of sodium nitrate to chloroplatinic acid.
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Spirotryprostatin A is an indolic alkaloid from the 2,5-Diketopiperazine class of natural products found in the Aspergillus fumigatus fungus. Spirotryprostatin A and several other indolic alkaloids (including Spirotryprostatin B, as well as other tryprostatins and cyclotryprostatins) have been found to have anti-mitotic properties, and as such they have become of great interest as anti-cancer drugs. Because of this, the total syntheses of these compounds is a major pursuit of organic chemists, and a number of different syntheses have been published in the chemical literature. One such total synthesis was published in 1999, which showed that the isopropylidene side chain was not necessary to the biological activity of the compound, leading to a number of new theorized analogues.
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Terpyridine was first synthesized by G. Morgan and F. H. Burstall in 1932 by the oxidative coupling of pyridines. This method, however, proceeded in low yields. More efficient syntheses have since been described, mainly starting from 2-acetylpyridine. One method produces an enaminone by the reaction of 2-acetylpyridine with N,N-dimethylformamide dimethyl acetal.
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X. The Rule of "Steric Control of Asymmetric Induction" in the Syntheses of Acyclic Systems Donald J. Cram, Fathy Ahmed Abd Elhafez J. Am. Chem. Soc.; 1952; 74(23); 5828-5835. Abstract He published over 350 research papers and eight books on organic chemistry, and taught graduate and post-doctoral students from 21 different countries.
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According to a laboratory procedure hydroxylamine-O-sulfonic acid can be prepared by treating hydroxylamine sulfate with fuming sulfuric acid (oleum). The industrial process is similar. :(NH3OH)2SO4 \+ 2SO3 → 2H2NOSO3H + H2SO4 The sulfonation of hydroxylamine can also be effected with chlorosulfonic acid by a method first published in 1925 and refined for Organic Syntheses.
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One structure type features six terminal halides and 12 edge-bridging halides. This motif is exemplified by tungsten(III) chloride, [Ta6Cl18]4−,Koknat, F. W.; Marko, D. J. "Tetradecachlorohexatantalum Octahydrate, Ta6Cl14.8H2O" Inorganic Syntheses, 2004, volume 34, pp. 187-191. . (describes Na4Ta6Cl18) Another common structure has six terminal halides and 8 bridging halides, e.g. Mo6Cl142−.
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The distinctive coloring has led to coining the term 'little blue box' for cyclophane, an important π-acceptor used to synthesize mechanically bonded structures. Stoddart maintains this standardized color scheme across all of his publications and presentations, and his style has been adopted by other researchers reporting mechanically interlocked molecules based on his syntheses.
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Keith Wylie Faulkner is a British academic specializing in the work of Gilles Deleuze. He received his Ph.D in philosophy from the University of Warwick, UK. He is known for authoring Deleuze and the Three Syntheses of Time on Deleuze's theory of time, which he calls the most important theory of time since Heidegger.
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Perhaps the most important members are zinc dialkyldithiophosphates, which are oil additives. Such compounds are prepared by the reaction of dialkoxydithiophoric acid with metal oxides, chlorides, and acetates.David E. Coldbery, W. Conard Fernelius, Maurice Shamma, "Chromium(III) O,O′-Diethyl Dithiophosphate" Inorganic Syntheses, 1960 volume 6, pp. 142–143. Structure of a zinc dialkyldithiophosphate.
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The Tp ligands are usually prepared from the reaction of pyrazole with potassium borohydride:S. Trofimenko ”Poly(1-Pyrazolyl)Borates, Their Transition-Metal Complexes, and Pyrazaboles” Inorganic Syntheses, 1970, Volume 12, p 99-109. :KBH4 \+ 3 C3H3N2H → K[HB(C3N2H3)3] + 3H2 Intermediates include the monopyrazolylborate ([H3B(C3N2H3)]−) and the bispyrazolylborate ([H2B(C3N2H3)2]−). KTp (m.p.
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Between 1930 and 1940 Zemplén continued research on the naturally occurring flavonoid-glycosides and succeeded in elucidating the structures of several of them, as well as accomplishing their total syntheses. His research contributed to the industrial isolation and application of flavonoids found in plants. In 1941 he was invited to give a lecture in Germany.
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Wieland-Miescher synthesis: a) water, acetic acid, hydroquinone (stabilizes EVK) b)L-proline, DMSO d) hydrogen, Raney nickel, sodium hydroxide e) methyl iodide, dioxane. specific rotation 68°. The required 2-methyl-1,3-cyclohexanedione can be prepared from resorcinolA. B. Mekler, S. Ramachandran, S. Swaminathan, and Melvin S. Newman Organic Syntheses, Coll. Vol. 5, p.
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Total world production, for comparison purposes expressed as HCl, is estimated at 20 Mt/year, with 3 Mt/year from direct synthesis, and the rest as secondary product from organic and similar syntheses. By far, most hydrochloric acid is consumed captively by the producer. The open world market size is estimated at 5 Mt/year.
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This THF-soluble complex is used in the synthesis of organoscandium compounds.Manzer, L. E., "Tetrahydrofuran Complexes of Selected Early Transition Metals", Inorganic Syntheses, 1982, volume 21, page 135-40. ScCl3 has been converted to its dodecyl sulfate salt, which has been investigated as a "Lewis acid-surfactant combined catalyst" (LASC) in aldol-like reactions.
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These principles have been applied in multiple natural product targets containing medium and large rings. The syntheses of cladiell-11-ene-3,6,7- triol, (±)-periplanone B,Still, W.C. J. Am. Chem. Soc. 1979, 101, 2493-2495. eucannabinolide, and neopeltolide are all significant in their usage of macrocyclic stereocontrol en route to obtaining the desired structural targets.
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Yukio Suzuki, Wakako Mori, Hiroyuki Ishizone, Koichi Naito, and Toshio Honda (1992) Concise Enantiospecific Syntheses of (+)-Eldanolide and (−)-cis-Whisky Lactone. Tetrahedron letters, volume 33, pages 4931-4932 The (3S,4R) isomer is extracted by the alcoholic beverage from some precursor substances in the oak wood.Masuda and Nishimura (1971), Branched nonalactones from some Quercus species.
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Cyclooctadiene rhodium chloride dimer is the organorhodium compound with the formula Rh2Cl2(C8H12)2, commonly abbreviated [RhCl(COD)]2 or Rh2Cl2(COD)2. This yellow-orange, air-stable compound is a widely used precursor to homogeneous catalysts.Giordano, G.; Crabtree, R. H. “Di-μ-chloro- bis(η4-1,5-cyclooctadiene)dirhodium(I)” Inorganic Syntheses, 1990, volume 28, pages 88-90.
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CSI is prepared by treating cyanogen chloride with sulfur trioxide, the product being distilled directly from the reaction mixture.Graf, R. "Chlorosulfonyl Isocyanate" Organic Syntheses, Collected Volume 5, pages 226ff. ::SO3 \+ ClCN → ClSO2NCO In this transformation, both the carbon and the nitrogen termini of CN are functionalized. The structure of CSI is represented as ClS(O)2-N=C=O.
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Allylpalladium(II) chloride dimer (APC) is a chemical compound with the formula [(η3-C3H5)PdCl]2. This yellow air-stable compound is an important catalyst used in organic synthesis.Tatsuno, Y.; Yoshida, T.; Otsuka, S. "(η3-allyl)palladium(II) Complexes" Inorganic Syntheses, 1990, volume 28, pages 342-345. It is one of the most widely used transition metal allyl complexes.
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In terms of applications, a popular allyl complex is allyl palladium chloride.Tatsuno, Y.; Yoshida, T.; Otsuka, S. "(η3-allyl)palladium(II) Complexes" Inorganic Syntheses, 1990, volume 28, pages 342-345. Allyl ligands are susceptible to nucleophilic addition, which can be useful in organic synthesis.Hartwig, J. F. Organotransition Metal Chemistry, from Bonding to Catalysis; University Science Books: New York, 2010.
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The Mukaiyama aldol reaction is the nucleophilic addition of silyl enol ethers to aldehydes catalyzed by a Lewis acid such as boron trifluoride (as boron trifluoride etherate) or titanium tetrachloride.3-Hydroxy-3-Methyl-1-Phenyl-1-Butanone by Crossed Aldol Reaction Teruaki Mukaiyama and Koichi Narasaka Organic Syntheses, Coll. Vol. 8, p.323 (1993); Vol.
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Peramivir is developed by structure-based drug design. After the influenza NA inhibitor activity of α/β-6-acetyl-amino-3,6-dideoxy -D-glycero- altro-2-nonulofuranosonic acid was reported by Yamamoto et al.,Yamamoto, T., Kumazawa, H., Inami, K., Teshima, T. & Shiba, T. 1992. Syntheses of sialic acid isomers with inhib- itory activity against neuraminidase.
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Soderquist JA, Najafi MR. "Selective Oxidation of Organoboranes with Anhydrous Trimethylamine-N-Oxide." J Org Chem. 1986;51:1330. doi: 10.1021/jo00358a032. Zweifel GS, Leung T, Najafi MR, Najdi S. "Stereoselective Syntheses of Alkenyl-Substituted 1,3-Dioxolanes or 4,7-Dihydro-1,3-dioxepins or an (E)-alpha,beta-Unsaturated Aldehyde from (Z)-2-Butene-1,4-diols" J Org Chem. 1985;50:2004.
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In 7 steps, this compound forms 123, which is then rearranged, in a similar manner to compound 114, to form the aconitine-like skeleton in 124. A racemic relay synthesis is completed to produce talatisamine (13). More recently, the laboratory of the late David Y. Gin completed the total syntheses of the aconitine alkaloids nominine and neofinaconitine.
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6,14-Endoethenotetrahydrooripavine is the central nucleus, or backbone, of a class of morphinan opioids known as the Bentley compounds and may be considered their "privileged scaffold". These include but are not limited to etorphine and buprenorphine. They usually have thebaine or oripavine as their precursor in their syntheses (and are thus termed "thevinols" and "orvinols", respectively).
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Beryllium chloride is prepared by reaction of the metal with chlorine at high temperatures:Irving R. Tannenbaum "Beryllium Chloride" Inorganic Syntheses, 1957, vol. 5, p. 22. :Be + Cl2 → BeCl2 BeCl2 can also be prepared by carbothermal reduction of beryllium oxide in the presence of chlorine.Cotton, F. A.; Wilkinson, G. (1980) Advanced Inorganic Chemistry John Wiley and Sons, Inc: New York, .
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Bropirimine synthesis: other syntheses: For the first step, the dianion from malonic acid half-ester is formed by treatment with butyllithium. Acylation of the anion with benzoyl chloride proceeds at the carbanion, which is more nucleophilic (because of the higher charge density). This tricarbonyl compound decarboxylates on acidification to the β-ketoester. Condensation with guanidine leads to the pyrimidone.
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A well known hydrogen silsesquioxane is [HSiO3/2]8. Early syntheses involved treatment of trichlorosilane with concentrated sulfuric acid, and fuming sulfuric acid, affording T10-T16 oligomers. The T8 cluster was also synthesized by the reaction of trimethylsilane with a mixture of acetic acid, cyclohexane, and hydrochloric acid. The Si-H groups are amenable to hydrosilylation.
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One of the earliest reported syntheses of this quinolinic acid was by Zdenko Hans Skraup, who found that methyl-substituted quinolines could be oxidized to quinolinic acid by potassium permanganate. This compound is commercially available. It is generally obtained by the oxidation of quinoline. Oxidants such as ozone, hydrogen peroxide, and potassium permanganate have been used.
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It is incompatible with ketones and primary alcohols, as it oxidizes them to aldehydes and carboxylic acids while being itself reduced to Cr3+. Therefore, CrO5 is a good oxidizing agent, even better than chromates and dichromates due to the presence of two reactive peroxo ligands, but due to its low stability it is not used in organic syntheses.
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Triphenylbismuth, BiPh3, was discovered to be a suitable alternative. Mercury and bismuth have similar electronegativity values and behave similarly in RTLE reactions. BiPh3 has been used to synthesize alkaline-earth metal amides and alkaline-earth metal cyclopentadienides. The difference between HgPh2 and BiPh3 in these syntheses was that the reaction time was longer when using BiPh3.
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DMPA is an odorless free flowing white crystalline solid and essentially non-toxic. DMPA has two different functional groups hydroxyl and carboxylic acid so the molecule can be used for a wide variety of syntheses. In addition to reaction with other chemicals, DMPA can also react with itself to produce esters via esterification as one example.
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Organoaluminium compounds are extremely pyrophoric and should be handled only under inert atmosphere. Dialkylaluminium hydrides and lithium aluminium hydride are both available commercially; the former is available either neat or in solutions that may be standardized using known procedures.Brown, H. C. Organic Syntheses via Boranes, Wiley, New York, 1975. Solvents and other reagents should be scrupulously dried.
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The addition is an anti-Markovnikov addition. Early work linked the addition to olefin polymerization and is therefore considered a first step into what was to become atom transfer radical polymerization. An example of Karasch addition is the synthesis of 1,1,3-trichloro-n-nonane from 1-octene, chloroform and ferric chloride](FeCl2)]. Organic Syntheses, Coll. Vol.
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From 1966 through 1974, he was a professor of chemistry at Nagoya University. Since 1974, Kishi has been a professor of chemistry at Harvard University. Kishi's research has focused on the total synthesis of complex natural products. The accomplishments of his research group include the total syntheses of palytoxin, mycolactones, halichondrins, saxitoxin, tetrodotoxin, geldanamycin, batrachotoxin and many others.
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Related reactions entail "HX additions" where X = silyl (hydrosilylation) and CN (hydrocyanation). Most large-scale industrial hydrogenations - margerine, ammonia, benzene-to- cyclohexane - are conducted with heterogeneous catalysts. Fine chemical syntheses, however, often rely on homogeneous catalysts. ;Carbonylations Hydroformylation, a prominent form of carbonylation, involves the addition of H and "C(O)H" across a double bond.
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Pyridine can be prepared by dealkylation of alkylated pyridines, which are obtained as byproducts in the syntheses of other pyridines. The oxidative dealkylation is carried out either using air over vanadium(V) oxide catalyst, by vapor- dealkylation on nickel-based catalyst, or hydrodealkylation with a silver- or platinum-based catalyst.Mensch, F. (1969). Erdöl Kohle Erdgas Petrochemie.
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Some synthetic macromolecules, such as catenanes and rotaxanes, dendrimers and hyperbranched polymers, and other assemblies, have molecular weights extending into the thousands or tens of thousands, where most ionization techniques have difficulty producing molecular ions. MALDI is a simple and fast analytical method that can allow chemists to rapidly analyze the results of such syntheses and verify their results.
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Francis's term "" refers to armed dictatorship without rule of law, or a Hegelian synthesis when the state tyrannically or oppressively regulates citizens' lives yet is unable to enforce fundamental protective law.Chilton Williamson, Jr.. "Synthetic Syntheses", Chronicles: A Magazine of American Culture, 3 October 2005. Archived.Kevin D. Williamson. "A Bit More on the Speech Police", National Review, 18 April 2014.
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The total synthesis of moroidin has not yet been described. Partial syntheses including the Leu- Trp and Trp-His linkages have been achieved. In their total synthesis of celogentin C, Castle and coworkers first obtained the Leu-Trp cross-link. The formation of this bond involved an intermolecular Knoevenagel condensation followed by radical conjugate addition and nitro reduction.
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When human symptoms started to be noticed around 1956 an investigation began. Fishing was officially banned in 1957. It was found that the Chisso Corporation, a petrochemical company and maker of plastics such as vinyl chloride, had been discharging heavy metal waste into the sea for decades. They used mercury compounds as catalysts in their syntheses.
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Sulfur chloride pentafluoride is an inorganic compound with the formula . It exists as a colorless gas at room temperature and is highly toxic, like most inorganic compounds containing the pentafluorosulfide (SF5) functional group.Nyman, F., Roberts, H. L., Seaton, T. "Sulfur Chloride Pentafluoride" Inorganic Syntheses, 1966, Volume 8, p. 160. The compound adopts an octahedral geometry with symmetry.
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Purines, however, are first synthesized from the sugar template onto which the ring synthesis occurs. For reference, the syntheses of the purine and pyrimidine nucleotides are carried out by several enzymes in the cytoplasm of the cell, not within a specific organelle. Nucleotides undergo breakdown such that useful parts can be reused in synthesis reactions to create new nucleotides.
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There are, however, a few problems with some syntheses. The Piloty-Robinson reaction competes with the formation of pyrazoline when the reactant is an aliphatic azine derived from a ketone. Also, under high temperatures and highly acidic solutions, azines derived from aldehydes are not stable. This prevents the formation of 2,5-disubstituted pyrroles (where R=H) using this method.
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It was noted that the synthesis worked even on cloudy days. In the previous syntheses the fluorine gas reactant had been purified to remove hydrogen fluoride. Šmalc and Lutar found that if this step is skipped the reaction rate proceeds at four times the original rate. In 1965, it was also synthesized by reacting xenon gas with dioxygen difluoride.
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11β-Hydroxyprogesterone (11β-OHP), also known as 21-deoxycorticosterone, as well as 11β-hydroxypregn-4-ene-3,20-dione, is a naturally occurring, endogenous steroid and derivative of progesterone. It is a potent mineralocorticoid. Syntheses of 11β-OHP from progesterone is catalyzed by the steroid 11β-hydroxylase (CYP11B1) enzyme, and, to a lesser extent, by the aldosterone synthase enzyme (CYP11B2).
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Triphenylphosphine selenide is an organophosphorus compound with the formula (C6H5)3PSe. It is a white solid which is soluble in most organic solvents. The compound is used in the preparation of other selenium compounds and is itself prepared by the reaction of triphenylphosphine with potassium selenocyanate.Philip Nicpon, Devon W. Meek "Triphenylphosphine Selenide" Inorganic Syntheses, 1967, Volume 10, 157–159.
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Selenium tetrafluoride (SeF4) is an inorganic compound. It is a colourless liquid that reacts readily with water. It can be used as a fluorinating reagent in organic syntheses (fluorination of alcohols, carboxylic acids or carbonyl compounds) and has advantages over sulfur tetrafluoride in that milder conditions can be employed and it is a liquid rather than a gas.
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In Drainage and stormwater management. Syntheses of best practices road salt management. Transportation Association of Canada: special issue on Synthesis of success in road salt management. 2-34. # Rosa Galvez-Cloutier, S. Saminathan, C. Boillot, G. Triffaut-Bouchet, A. Bourget and G. Soumis-Dugas (2012) Testing Efficiency and Ecocompatibility of Various In-lake Restoration Techniques Env.
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The zinc zinc-oxide cycle is a two step thermochemical process based on zinc and zinc oxide for hydrogen production. Zinc chloride is often added to lumber as a fire retardant and sometimes as a wood preservative. It is used in the manufacture of other chemicals. Zinc methyl () is used in a number of organic syntheses.
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Illustrative is the conversion of sodium perrhenate to the tetrabutylammonium salt:J. R. Dilworth, W. Hussain, A. J. Hutson, C. J. Jones, F. S. Mcquillan "Tetrahalo Oxorhenate Anions" Inorganic Syntheses 1997, volume 31, pages 257–262. :NaReO4 \+ N(C4H9)4Cl → N(C4H9)4[ReO4] + NaCl The tetrabutylammonium salt precipitates from the aqueous solution. It is soluble in dichloromethane.
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Syntheses of these approaches are also becoming accepted and recognised in their own right (e.g. The Chiron Approach: Chiron Association of Body Psychotherapists).Hartley, L. (Ed.) (2009) Contemporary Body Psychotherapy. Routledge. Alongside the body psychotherapies built directly on the work of Reich, there is a branch of post-Jungian body psychotherapies, developed from Jung's idea of the 'somatic unconscious'.
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Douglas T. Kenrick is Professor of Psychology at Arizona State University. His research and writing integrate three scientific syntheses of the last few decades: evolutionary psychology, cognitive science, and dynamical systems theory.Kenrick, D. T., Maner, J.K., Butner, J., Li, N.P., Becker, D.V., & Schaller, M. (2002). Dynamic Evolutionary Psychology: Mapping the domains of the new interactionist paradigm.
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Cyclotrimerization of formaldehyde affords 1,3,5-Trioxane: :450px 1,3,5-Trithiane is the cyclic trimer of the otherwise unstable species thioformaldehyde. This heterocycle consists of a six-membered ring with alternating methylene bridges and thioether groups. It is prepared by treatment of formaldehyde with hydrogen sulfide.Bost, R. W.; Constable, E. W. "sym-Trithiane" Organic Syntheses, Collected Volume 2, p.
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Schematic for the syntheses of Napelline Deoxydelphonine, and Talatisamine Wiesner Syntheses of Napelline Deoxydelphonine, and Talatisamine The total synthesis of napelline (Scheme a) begins with aldehyde 100. In a 7 step process, the A-ring of napelline is formed (104). It takes another 10 steps to form the lactone ring in the pentacyclic structure of napelline (106). An additional 9 steps creates the enone-aldehyde 107. Heating in methanol with potassium hydroxide causes an aldol condensation to close the sixth and final ring in napelline (14). Oxidation then gives rise to diketone 108 which was converted to (±)-napelline (14) in 10 steps. A similar process is demonstrated in Wiesner's synthesis of 13-desoxydelphinone (Scheme c). The first step of this synthesis is the generation of a conjugated dienone 112 from 111 in 4 steps.
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A promiscuous activity is a non-native activity the enzyme did not evolve to do, but arises due to an accommodating conformation of the active site. However, the main activity of the enzyme is a result not only of selection towards a high catalytic rate towards a particular substrate to produce a particular product, but also to avoid the production of toxic or unnecessary products. For example, if a tRNA syntheses loaded an incorrect amino acid onto a tRNA, the resulting peptide would have unexpectedly altered properties, consequently to enhance fidelity several additional domains are present. Similar in reaction to tRNA syntheses, the first subunit of tyrocidine synthetase (tyrA) from Bacillus brevis adenylates a molecule of phenylalanine in order to use the adenyl moiety as a handle to produce tyrocidine, a cyclic non-ribosomal peptide.
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He was known for pushing mineral analysis beyond analytical results. He sought compilations of the associations, alterations, and syntheses of each mineral sample. His study "Constants of Nature" (Smithsonian Institution 1876) was one of the first collections of both physical and chemical constants. The USGS's Atomic Weights series became standard references for the chemistry and geochemistry professions and academic fields.
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He then moved to Harvard University. With his research assistant and wife Mary Peters Fieser (MA, 1936, Radcliffe) he coauthored eight books and the first seven volumes of the classic series Reagents for Organic Synthesis known popularly among chemists as "Fieser and Fieser". He was also an editor and contributor for Organic Syntheses. Fieser had two chemical reagents named for him.
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Off Our Backs. In the early 1970s, conflicts began to emerge due to different syntheses of lesbian, feminist and transgender political movements, particularly in the United States. San Francisco trans activist and entertainer Beth Elliott became the focus of debate over whether to include transgender lesbians in the movement, and she was eventually blacklisted by her own movement.Henry Rubin (2003).
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Dalton Transactions publishes articles on all aspects of the chemistry of inorganic and organometallic compounds, including bioinorganic, biological inorganic, and solid-state inorganic chemistry; the application of physicochemical techniques to the study of their structures, properties, and reactions, including kinetics and mechanisms; synthesis and characterisation of new inorganic materials; homogeneous and heterogeneous catalysis; new or improved experimental techniques and syntheses.
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His research continued at Harvard University in 1933 as a National Research Council Fellow. In 1934, he joined the faculty of Bryn Mawr College. There, his research included the first syntheses of a number of barbiturates including delvinyl sodium. At Bryn Mawr, Cope also developed a reaction involving the thermal rearrangement of an allyl group which eventually became known as the Cope rearrangement.
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Most reactions of adamantane occur via the 3-coordinated carbon sites. They are involved in the reaction of adamantane with concentrated sulfuric acid which produces adamantanone. 420px The carbonyl group of adamantanone allows further reactions via the bridging site. For example, adamantanone is the starting compound for obtaining such derivatives of adamantane as 2-adamantanecarbonitrile2-Adamantanecarbonitrile Organic Syntheses, Coll. Vol.
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Tube furnace being used during the synthesis of aluminium chloride. A tube furnace is an electric heating device used to conduct syntheses and purifications of inorganic compounds and occasionally in organic synthesis. One possible design consists of a cylindrical cavity surrounded by heating coils that are embedded in a thermally insulating matrix. Temperature can be controlled via feedback from a thermocouple.
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Some research suggests that it can be made by the cyclofunctionalization of cycloalkenyl systems. Under kinetically controlled conditions, this process generally results in exo cyclization and forms bridged ring systems like those found in picrotoxin. Additionally, several syntheses have been proposed for picrotoxinin and picrotin, the two molecules that make up picrotoxin. In 1980, a process to convert picrotoxinin to picrotin was discovered.
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For example, treatment of dibutyltin dichloride with lithium aluminium hydride gives the dibutyltin dihydride, a colourless distillable oil:"Organometallic Syntheses: Nontransition-Metal Compounds" John Eisch, Ed. Academic Press: New York, 1981. . :{Bu2SnCl2} + 1/2LiAlH4 -> {Bu2SnH2} + 1/2LiAlCl4 The Wurtz-like coupling of alkyl sodium compounds with tin halides yields tetraorganotin compounds. Hydrostannylation involves the metal- catalyzed addition of tin hydrides across unsaturated substrates.
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The molecule is commonly used as in biochemistry and cell biology laboratories as a selective inhibitor of the proteasome. The first total synthesis of lactacystin was developed in 1992 by Corey and Reichard,"Total Synthesis of Lactacystin" Corey, E. J.; Reichard, G. A. J. Am. Chem. Soc. 1992, 114, 10677. and a number of other syntheses of this molecule have also been published.
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The Cram's rule of asymmetric induction developed by Donald J. Cram in 1952Studies in Stereochemistry. X. The Rule of "Steric Control of Asymmetric Induction" in the Syntheses of Acyclic Systems Donald J. Cram, Fathy Ahmed Abd Elhafez J. Am. Chem. Soc.; 1952; 74(23); 5828–5835. Abstract is an early concept relating to the prediction of stereochemistry in certain acyclic systems.
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Stork-Zhao Olefination Below is example of employing both Takai olefination and Stork- Zhao olefination in total synthesis of (+)-3-(E)- and (+)-3-(Z)-Pinnatifidenyne.Kim, Hyoungsu, et al. "Construction of eight- membered ether rings by olefin geometry-dependent internal alkylation: First asymmetric total syntheses of (+)-3-(E)-and (+)-3-(Z)-pinnatifidenyne." Journal of the American Chemical Society 125.34 (2003): 10238-10240.
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The musicologist David Charlton evaluated his influence by saying "While the musical language of Reyer, Massenet and Saint-Saens presented syntheses of current practice, that of Emmanuel Chabrier (1841–1894) was a catalyst: his work became the cradle of French modernism".The New Oxford History of Music. Romanticism 1830–1890. Vol IX, VI Opera 1850–90 (b) France – David Charlton. P405-409.
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Paolo Chini (1928–1980) was an Italian chemist, known as the "King of the Clusters". He has been a pioneer in Metal carbonyl cluster syntheses. He developed and improved quantitative methods for the synthesis of large carbonyl clusters, such as thermal degradation and redox condensation. Today these methods are still the main approaches to the synthesis of high nuclearity heterometallic clusters.
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A variety of syntheses of lanthionine have been published including sulfur extrusion from cystine,Harpp, D. N.; Gleason, J. G. (1971) Preparation and Mass Spectral Properties of Cystine and Lanthionine Derivatives. Novel Synthesis of L-Lanthionine by Selective Desulfurization. Journal of Organic Chemistry, 36, 73-80. ring opening of serine β-lactone, and hetero-conjugate addition of cysteine to dehydroalanine.
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After attending secondary school in Appingedam where he graduated in 1972, Meijer received his education in Organic Chemistry at the University of Groningen. He obtained his MSc degree in 1978, and subsequently his PhD degree under supervision of Professor Hans Wijnberg in 1982. Meijer graduated summa cum laude with his thesis on 'Chemiluminescence in action: syntheses, properties, and applications of 1,2-dioxetanes'.
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Structure of the phenylsodium-PMDTA adduct, hydrogen atoms omitted for clarity. The first syntheses of phenylsodium which employed the organomercury route seemed to yield a light brown powder. It was discovered by Schlenk that this product was contaminated by a sodium amalgum. Centrifugation allowed for the isolation of pure phenylsodium which appears as a yellowish-white amorphous powder which readily bursts into flames.
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Polymers made with aromatic monomers have a tendency to condense into chars upon combustion, decreasing the amount of flammable gas that is released. Syntheses of these types of polymers generally employ prepolymers which are further reacted to form the fire-resistant polymers.Akinseye, T. D.; Harruna, I. I.; Bota, K. B. Processable Precursors .4. Synthesis and Characterization of Processable Precursors to Poly (Phenylene Bixbenzoxazoles).
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However, many of the initiated syntheses are aborted before the transcripts reach a significant length (~10 nucleotides). During these abortive cycles, the polymerase keeps making and releasing short transcripts until it is able to produce a transcript that surpasses ten nucleotides in length. Once this threshold is attained, RNA polymerase passes the promoter and transcription proceeds to the elongation phase. Forluvoft.
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The 8-glider synthesis combines two of the four-glider units described in this figure. Glider collisions designed to result in certain patterns are also called glider syntheses. Patterns such as blocks, beehives, blinkers, traffic lights, even the uncommon Eater, can be synthesized with just two gliders. It takes three gliders to build the three other basic spaceships, and even the pentadecathlon oscillator.
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Frequently seen electrophiles in organic syntheses include cations such as H+ and NO+, polarized neutral molecules such as HCl, alkyl halides, acyl halides, and carbonyl compounds, polarizable neutral molecules such as Cl2 and Br2, oxidizing agents such as organic peracids, chemical species that do not satisfy the octet rule such as carbenes and radicals, and some Lewis acids such as BH3 and DIBAL.
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A large theme of his work is molecular topology, specifically mechanically-interlocked molecular architectures. He has described syntheses of catenanes and molecular knots based on coordination complexes. He was elected a correspondent member of the French Academy of Sciences on 26 March 1990, and became a member on 24 November 1997. He is currently emeritus professor at the University of Strasbourg (Unistra).
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RDX is classified by chemists as a hexahydro-1,3,5-triazine derivative. It is obtained by treating hexamine with white fuming nitric acid. :400px This nitrolysis reaction also produces methylene dinitrate, ammonium nitrate, and water as byproducts . The overall reaction is: :C6H12N4 \+ 10 HNO3 → C3H6N6O6 \+ 3 CH2(ONO2)2 \+ NH4NO3 \+ 3 H2O Modern syntheses employ hexahydro triacyl triazine as it avoids formation of HMX.
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Methane, CH4; it is one of the simplest organic compounds. In chemistry, organic compounds are generally any chemical compounds that contain carbon- hydrogen bonds. Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known. The study of the properties, reactions, and syntheses of organic compounds comprises the discipline known as organic chemistry.
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The application of the Johnson–Corey–Chaykovsky reaction in organic synthesis is diverse. The reaction has come to encompass reactions of many types of sulfur ylides with electrophiles well beyond the original publications. It has seen use in a number of high-profile total syntheses, as detailed below, and is generally recognized as a powerful transformative tool in the organic repertoire.
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In 1978 he was a visiting scientist at the Technical University of Berlin in the group of Prof. Ernst Lippert. He became a lecturer (Dozent) in 1979 after submission of a habilitation thesis entitled Syntheses and Spectroscopic Properties of Laser Dyes and Fluorescent Indicators. In the years thereafter, he was a visiting professor at Tufts University, Hebrew University of Jerusalem, and Wuhan University.
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Gaining insight from this work, Tsuji hypothesized that a similar activation could take place to form carbon- carbon bonds. In 1965, Tsuji reported work that confirmed his hypothesis. By reacting an allylpalladium chloride dimer with the sodium salt of diethyl malonate, the group was able to form a mixture of monoalkylated and dialkylated product.Organic syntheses by means of noble metal compounds XVII.
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Allan R. Robinson, Kenneth H. Brink The Global Coastal Ocean: Regional Studies and Syntheses, Harvard University Press, 2005 pp.775–783 Some islands mostly consist of sand and ice and gradually erode. The total catchment area is 1,342,000 km2. Among the rivers flowing into the East Siberian Sea, the Indigirka, Alazeya, Chukochya, Kolyma, Rauchua, Chaun, and Pegtymel are the most important.
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Structure of Fe5C(CO)15. Most molecular carbido complexes are clusters, usually featuring carbide and a six-fold bridging ligand. Examples include [Rh6C(CO)15]2-,S. Martinengo, D. Strumolo, P. Chini, "Dipotassium μ6-Carbido- Nona-μ-Carbonyl-Hexacarbonylhexarhodate(2-) K2[Rh6(CO)6(μ-CO)9-μ-C]" Inorganic Syntheses 1980; 20: 212–215 and [Ru6C(CO)16]2−.
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This thiocyanate compound can be used as a transesterification catalyst. Although it is not well known, it has been used in a number of total syntheses. In this application, the reaction occurs via the displacement of the bridging isothiocyanate ligands with the incoming alcohol to form an alcohol-bridged active catalyst. Tin acts as the Lewis acid, and gives the transesterified product.
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Harry Laurence Anderson, FRS is a British chemist in the Department of Chemistry, University of Oxford. He is well known for his contributions in the syntheses of supramolecular systems (porphyrin nanorings and nanowires), exploration of the extraordinary physical properties of large pi-conjugated systems, and synthesis of cyclo[18]carbon. He is a Professor of Chemistry at Keble College, Oxford.
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This picture illustrates the main steps in the Kreis synthesis of (-)Dendrobine There have been 3 successful enantioselective syntheses of dendrobine reported with yields ranging from 0.2-4.0%. The structure of dendrobine is intriguing due to its tetracyclic ring system with seven contiguous stereocenters. Most recently, a full synthesis of (-)-dendrobine was carried out by Kreis et al. with a yield of 4.0%.
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Dimethylphosphine is the organophosphorus compound with the formula (CH3)2PH, often written Me2PH. It is a malodorous gas that condenses to a colorless liquid just below room temperature. Although it can be produced by methylation of phosphine, a more practical synthesis involves the reduction of tetramethyldiphosphine disulfide with tributylphosphine:A. Trenkle, H. Vahrenkamp “Dimethylphosphine” Inorganic Syntheses 1982, volume 21, p. 180.
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Yields for these ether syntheses are traditionally low when reaction times are shortened, which can be the case with undergraduate laboratory class periods. Without allowing the reactions to reflux for the correct amount of time (anywhere from 1–8 hours from 50 to 100 °C) the reaction may not proceed to completion generating a poor overall product yield. To help mitigate this issue microwave-enhanced technology is now being utilized to speed up the reaction times for reactions such as the Williamson ether synthesis. This technology has transformed reaction times that required reflux of at least 1.5 hours to a quick 10-minute microwave run at 130 °C and this has increased the yield of ether synthesized from a range of 6-29% to 20-55% (data was compiled from several different lab sections incorporating the technology in their syntheses).
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There is no reported total synthesis of chloroeremomycin, although there are several total syntheses of vancomycin. The structures of vancomycin and chloroeremomycin are very similar, differing only in the glycosylation sites. Vancomycin is glycosylated at aa4 with a (2-beta1)-Glc- vancosamine disaccharide. As mentioned above, chloroeremomycin is glycosylated at aa4 with a (2-beta1)-Glc-epivancosamine disaccharide and at aa6 with a beta1-epivancosamine saccharide.
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Hydrated chloroacetaldehyde is produced by the chlorination of aqueous vinyl chloride: :ClCH=CH2 \+ Cl2 \+ H2O → ClCH2CHO + 2 HCl It can also be prepared from vinyl acetate or by careful chlorination of acetaldehyde. The related bromoacetaldehyde is prepared via bromination of vinyl acetate. It also rapidly forms an acetals in the presence of alcohols.S. M. McElvain and D. Kundiger "Bromoacetal" Organic Syntheses 1943, volume 23, p. 8. .
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Roseophilin is an antibiotic isolated from Streptomyces griscovirides shown to have antitumor activity. The chemical structure can be considered in terms of two components, a macrotricyclic segment and a heterocyclic side-chain. Several laboratory syntheses of roseophilin (e.g., those of Trost, Fürstner, Salamone) are based upon the Paal-Knorr synthesis, and two others are based on the Nazarov cyclization reaction (those of Tius, Frontier).
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It deals with events in their depth and structure rather than in their contiguity in time. Where passive syntheses created a field of 'me's,' active synthesis is performed by 'I.' In the Freudian register, this synthesis describes the displaced energy of Eros, which becomes a searching and problematizing force rather than a simple stimulus to gratification. Proust and Lacan are key authors for this layer.
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The natural route to synthesis includes polyketide synthase components. The carbon chains of Amphotericin B are assembled from sixteen 'C2' acetate and three 'C3'propionate units by polyketide syntheses (PKSs). Polyketide biosynthesis begins with the decarboxylative condensation of a dicarboxylic acid extender unit with a starter acyl unit to form a β-ketoacyl intermediate. The growing chain is constructed by a series of Claisen reactions.
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Dimethyl maleate is used in many organic syntheses as a dienophile for diene synthesis. It is used as an additive and intermediate for plastics, pigments, pharmaceuticals, and agricultural products. It is also an intermediate for the production of paints, adhesives, and copolymers."Dimethyl maleate", Chemical Land 21 Dimethyl maleate has also found use in applications where improvements in the hardness and toughness of polymer films are desired.
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Developments have continued over the years, including in the catalysts used. Recently, it was found that Ni-B/MgO showed superior catalytic activity to that of Raney nickel and other common catalysts that have been used in the hydrogenation of sulfolene. Other syntheses have also been developed, such as oxidizing tetrahydrothiophene with hydrogen peroxide. This reaction produces tetramethylene sulfoxide, which can then be further oxidized.
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Suib has conducted research in the areas of solid state inorganic chemistry, physical and environmental chemistry, plasma chemistry, inorganic photochemistry and photo- catalysis. He has worked on the synthesis of new adsorbents, batteries, catalysts, ceramics, composites, sensors, and semiconductors. His research includes the study of redox catalytic cycles, green syntheses, heterogeneous catalysis and characterization of systems using structural, crystallographic, surface, electrochemical, luminescence, microscopic and EPR techniques.
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DTDP- glucose goes on to form a variety of compounds in nucleotide sugars metabolism. Many bacteria utilize dTDP-glucose to form exotic sugars that are incorporated into their lipopolysaccharides or into secondary metabolites such as antibiotics. During the syntheses of many of these exotic sugars, dTDP- glucose undergoes a combined oxidation/reduction reaction via the enzyme dTDP- glucose 4,6-dehydratase, producing dTDP-4-keto-6-deoxy-glucose.
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The solid adopts a layered structure but upon evaporation, the species becomes dimeric. In contrast VOCl3 and VOBr3 remain tetrahedral in all states, being volatile liquids at room temperature.Holleman, A. F.; Wiberg, E. "Inorganic Chemistry" Academic Press: San Diego, 2001. . In organic synthesis, VOF3 is often used for the oxidative coupling of phenolic rings, for example in the syntheses of vancomycin and its analogues.
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The book has information on how to produce crystal methamphetamine through six different methods. It also has data on how to synthesize MDMA or MDA, and how to synthesize methcathinone by oxidation of ephedrine. It also contains syntheses for precursor materials such as phenylacetone, ephedrine, methylamine, and alkyl nitrites. Previous editions of Secrets of Methamphetamine Manufacture have had some criticism: see for example Eleusis v.
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THPC can be synthesized with high yield by treating phosphine with formaldehyde in the presence of hydrochloric acid. :PH3 \+ 4 H2C=O + HCl → [P(CH2OH)4]Cl THPC is commonly used to prepare tris(hydroxymethyl)phosphine by treating it with aqueous sodium hydroxide.M. Caporali, L. Gonsalvi, F. Zanobini, M. Peruzzini "Synthesis of the Water-Soluble Bidentate (P,N) Ligand PTN(Me)" Inorg. Syntheses, 2011, Vol.
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Since inhibition of SERCA is a mechanism of action that has been used to target solid tumors, thapsigargin has attracted research interest. A prodrug of thapsigargin, mipsagargin, is currently undergoing clinical trials for the treatment of glioblastoma. The biological activity has also attracted research into the laboratory synthesis of thapsigargin. To date, three distinct syntheses have been reported: one by Steven V. Ley, one by Phil Baran.
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In 1911, Köllisch published his doctoral dissertation on the topic of indole synthesis from hydrazones under Otto Diels at the University of Berlin.Köllisch: Zur Kenntnis des Diacetyls. I. Über die Brauchbarkeit der Diacetylphenylhydrazone für Kondensationen. II. Über Versuche zur Ueberführung des Diacetyls in eine Ketotetrose, Inaugural-Dissertation, Berlin: E. Ebering 1911 Hochspringen↑ While at Merck, Dr Köllisch was involved in investigating syntheses for methylhydrastinine and hydrastinine.
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The Feist–Benary synthesis is a classic way to synthesize furans, although many syntheses have been developed. One of the simplest synthesis methods for furans is the reaction of 1,4-diketones with phosphorus pentoxide (P2O5) in the Paal–Knorr synthesis. The thiophene formation reaction of 1,4-diketones with Lawesson's reagent also forms furans as side products. Many routes exist for the synthesis of substituted furans.
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The central C4SN ring is folded in phenothiazines. The compound was originally prepared by Bernthsen in 1883 via the reaction of diphenylamine with sulfur, but more recent syntheses rely on the cyclization of 2-substituted diphenyl sulfides. Few pharmaceutically significant phenothiazines are prepared from phenothiazine,Gérard Taurand, "Phenothiazine and Derivatives" in Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, 2005. although some of them are.
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Other acids of noncoordinating anions, such as fluoroboric acid and hexafluorophosphoric acid are susceptible to hydrolysis, whereas perchloric acid is not. Despite hazards associated with the explosiveness of its salts, the acid is often preferred in certain syntheses. For similar reasons, it is a useful eluent in ion-exchange chromatography. It is also used for electropolishing or etching of aluminium, molybdenum, and other metals.
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In 2010, Feihe Huang et al.Zhang, Z.; Xia, B.; Han, C.; Yu, Y.; Huang, F. Syntheses of Copillar[5]arenes by Co-oligomerization of Different Monomers, Organic Letters, 2010, 12, 3285-3287. introduced three new ways to synthesize copillararenes, which are composed of different repeating units. It is easier to selectively functionalize copillararenes, helping to generate interesting physical properties, conformations, and host–guest binding interactions.
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In 2017 Sarpong delivered a TED talk The face of disease in Sub-Saharan Africa, where he encouraged his audience to reevaluate the face of disease in Africa. He serves on the editorial boards of Organic Syntheses, Accounts of Chemical Research and Synlett. Sarpong is committed to improving diversity within the chemistry community, and has supported many scholars in the early stages of their academic careers.
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Acetone peroxides are unwanted by-products of some oxidation reactions such as those used in phenol syntheses. Due to their explosive nature, their presence in chemical processes and chemical samples creates potential hazardous situations. Accidental occurrence at illicit MDMA laboratories is possible. Numerous methods are used to reduce their appearance, including shifting pH to more alkaline, adjusting reaction temperature, or adding inhibitors of their production.
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Velleral (2,2,8-trimethyl-3,3a,8,8a-tetrahydro-1H-azulene-5,6-dicarbaldehyde) is a sesquiterpene dialdehyde found in certain mushrooms, like Lactarius torminosus and Lactarius vellereus, after which it was named. The compound is thought to be part of a chemical defense system that protects the mushrooms against predation. First isolated in 1969, and characterized structurally in 1973, velleral has antimicrobial activity. Several syntheses have been devised.
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Ernestine W. Hill, John S. Bradley, "Tetrairon Carbido Carbonyl Clusters" Inorganic Syntheses, 1990, Volume 27, Pages: 182–188. Lewis, J., Nelson, W. J. H., McPartlin, M., "The synthesis of the cluster dianion [Os10C(CO)24]2- by pyrolysis. X-Ray structure analysis of [N(PPh3)2]2[Os10C(CO)24] and [Os5C(CO)14H(NC5H4)]", Journal of the Chemical Society, Dalton Transactions 1982, 2099.
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The Bouveault–Blanc reduction is a chemical reaction in which an ester is reduced to primary alcohols using absolute ethanol and sodium metal. It was first reported by Louis Bouveault and Gustave Louis Blanc in 1903. Bouveault and Blanc demonstrated the reduction of ethyl oleate and n-butyl oleate to oleyl alcohol. modified versions of which were subsequently refined and published in Organic Syntheses.
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In the east, Songhay, Bozo, and Dogon people predominate, while the Fula people, formerly nomadic, have settled in patches across the nation. Tuareg and Maure peoples continue a largely nomadic desert culture, across the north of the nation. The interaction of these communities (along with dozens of other smaller ethnicities) have created a Malian culture, marked by heterogeneity, as well as syntheses where these traditions intermix.
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The reagent is named after two chemists from Ciba Geigy, Karl Miescher and Peter Wieland (not to be confused with Heinrich Otto Wieland). Examples of syntheses performed using the optically active enantiomer of this diketone as a starting material are that of ancistrofuran Ciceri, Paola, Demnitz, F.W. Joachim, Souza, Márcia C.F. de, Lehmanna, Maik. A Common Approach to the Synthesis of Monocyclofarnesyl Sesquiterpenes. J. Braz. Chem. Soc.
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See also Culianu, pp. 75–76 As seen by Vanhese, the Morning Star is a syntheses of incubi (he appears to Cătălina in her dreams) and Lucifer (with whom he shares the celestial attribute).Vanhese, pp. 180–185 She argues that, with Eminescu's poem, "the myth of the Romantic demon reaches its most accomplished expression in European culture", equaled in visual arts by Mikhail Vrubel's Demon Seated.
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At high temperatures, Ru3(CO)12 converts to a series of clusters that contain interstitial carbido ligands. These include Ru6C(CO)17 and Ru5C(CO)15. Anionic carbido clusters are also known, including [Ru5C(CO)14]2− and the bioctahedral cluster [Ru10C2(CO)24]2−.Nicholls, J. N.; Vargas, M. D. "Carbido-Carbonyl Ruthenium Cluster Complexes" Inorganic Syntheses, 1989, volume 26, pages 280-85.
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Nitrous acid is used to prepare diazonium salts: :HNO2 \+ ArNH2 \+ H+ → + 2 H2O where Ar is an aryl group. Such salts are widely used in organic synthesis, e.g., for the Sandmeyer reaction and in the preparation azo dyes, brightly colored compounds that are the basis of a qualitative test for anilines.Clarke, H. T.; Kirner, W. R. "Methyl Red" Organic Syntheses, Collected Volume 1, p.374 (1941).
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Sulfur is boiled in excess aniline over several hours to produce three isomers (1,1'; 1,4; 4,4') of TDA. The same journal documents syntheses of similar and overlapping compounds by Merz and Weith in 1871, and K. A. Hoffman in 1894. A study by Nietzki and Bothof shows indications that including an oxide of lead may maximize the yield of the 4,4' variant that this page refers to.
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Carreira began his independent research career on the Caltech faculty and became a full professor in 1997. While there, he received several awards for successful new faculty and for his skilled teaching. He has been a full professor of chemistry at ETH Zürich since 1998. Carreira has coauthored and coedited several major reference works in the total synthesis field, including volume 93 of Organic Syntheses.
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Pimelic acid has been synthesized from cyclohexanone and from salicylic acid. In the former route, the additional carbon is supplied by dimethyloxalate, which reacts with the enolate. In other syntheses, pimelic acid is made from cyclohexene-4-carboxylic acid, and a fourth method also exists based on the 1,4 reaction of malonate systems with acrolein. Several patents exist for the production of pimelic acid.
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Some species produce many extra copies of genes, such as amphibians, which may have up to 1 or 2 million copies. A complementary mechanism is partly dependent on syntheses of other cells. In amphibians, birds, and insects, yolk is made by the liver (or its equivalent) and secreted into the blood. Neighboring accessory cells in the ovary can also provide nutritive help of two types.
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Structure of one of several ferric citrate complexes.Ferric citrate easily forms coordination complexes,Xiang Hao, Yongge Wei, Shiwei Zhang (2001): "Synthesis, crystal structure and magnetic property of a binuclear iron(III) citrate complex". Transition Metal Chemistry, volume 26, issue 4, pages 384–387. I. Shweky, A. Bino, D. P. Goldberg, S. J. Lippard (1994): "Syntheses, structures, and magnetic-properties of 2 dinuclear iron(III) citrate complexes".
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382 mg/kg in mice, therefore, much less toxic than glutaraldehyde and many other commonly used synthetic cross-linking reagents. Furthermore, genipin can be used as a regulating agent for drug delivery, as the raw material for gardenia blue pigment preparation, and as the intermediate for alkaloid syntheses. In vitro experiments have shown that genipin blocks the action of the enzyme uncoupling protein 2.
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Russell P. Hughes (born December 23, 1946) an American/British chemist, is the Frank R. Mori Professor Emeritus and Research Professor in the Department of Chemistry at Dartmouth College. His research interests are in organometallic chemistry, with emphasis on the chemistry of transition metal interacting with fluorocarbons. His work in this area led to several creative syntheses of complexes between metal complexes and perfluorinated hydrocarbon fragments.
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Crystal structure of a rotaxane with an α-cyclodextrin macrocycle. Template directed syntheses ubiquitously exist in nature (protein biosynthesis, etc.), which provides inspiration for synthesising artificial supramolecular systems. Using porphyrin monomers/oligomers and molecular templates of various sizes, porphyrin nanoring systems can be constructed with high versatility. These supramolecular systems also bear appealing co- ordination properties, providing inspirations for the co-ordination phenomena existing in nature.
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For most applications, the potassium and sodium salts can be used interchangeably. Potassium cyanate is often preferred to the sodium salt, which is less soluble in water and less readily available in pure form. Potassium cyanate is used as a basic raw material for various organic syntheses, including, urea derivatives, semicarbazides, carbamates and isocyanates. For example, it is used to prepare the drug hydroxyurea.
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DECA-press Agency is a news agency from Moldova. It was launched in 1997. According to its official website, Deca-press provides daily news, commentaries, syntheses, articles and interviews to its clients which depict events or social, economic and political problems held in Moldova, covering all the major interest areas for information consumers. It is located in Bălți, Moldova on 18, Mihai Viteazul street, 3rd floor.
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Other syntheses of epothilones have been published by Nicolaou, Schinzer, Mulzer, and Carreira. In this approach, key building blocks aldehyde, glycidols, and ketoacid were constructed and coupled to olefin metathesis precursor via an aldol reaction and then an esterification coupling. Grubbs' catalyst was employed to close the bis terminal olefin of the precursor compound. The resulting compounds were cis- and tran-macrocyclic isomers with distinct stereocenters.
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HNLs and the action they mediate is a key target for study of protein engineering, as the formation of mandelonitrile is a key step in a wide variety of organic syntheses with medical and therapeutic potential. The step mediated by these enzymes is essential to the synthesis of stereospecific bond formation in (R)-Salbutamol bronchodilators, (S)-amphetamines, (1R, 2S)-(-)-ephedrine bronchodilators,Jackson WR., Jacob HA., Matthew BR., Jayatilake GS., Watson KG. Stereoselctive syntheses of ephedrine and related 2-aminoalcohols of high optical purity from protected cyanohydrins. Tetrahedron Lett. 1990; 31:1447-1450 in addition to many others, including Lipitor,Maureen AR. Biocatalysis buzz, deals underscore interest in biotechnology-based methods to improve chemical processes. Chem Eng News 2002; 80:86 Thalidomide,Ziegler T., Horsch B., Effenberger F., A convenient route to (R)-α-hydroxy carboxylic acids and (2R)-1-amin-2-alkanols from (R)-cyanohydrins.
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Due to the ongoing research involving radiofluorinated molecules and their various uses, the demand for suitable syntheses has increased over the years. In order for synthetic methods to be considered viable, the process must be rapid and efficient as well as compatible with the forms of 18F with are available. In many cases, the synthesis must also be capable of regio- and stereo-specificity. Positron Emission of Fluorine-18.
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At last, usually under heating conditions, the elimination of water molecule yields the cyclized α,β-unsaturated ketone. Fig. 2: Intramolecular aldol reaction in the total synthesis of (+)-Wortmannin. Intramolecular aldol reactions have been widely used in total syntheses of various natural products, especially alkaloids and steroids. An example is the application of an intramolecular aldol reaction in the ring closure step for total synthesis of (+)-Wortmannin by Shigehisa, et al.
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These reactions are often catalyzed by protein enzymes. Enzymes increase the rates of biochemical reactions, so that metabolic syntheses and decompositions impossible under ordinary conditions can occur at the temperatures and concentrations present within a cell. The general concept of a chemical reaction has been extended to reactions between entities smaller than atoms, including nuclear reactions, radioactive decays, and reactions between elementary particles, as described by quantum field theory.
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Carboxylation of adamantane was first reported in 1960, using formic acid as a carboxylating agent and carbon tetrachloride as a solvent. 500px tert-butanol (t-BuOH) and sulfuric acid were added to generate adamantane cation; the cation was then carboxylated by carbon monoxide generated in situ in the interaction between the formic and sulfuric acids. The fraction of carboxylated adamantane was 55-60%.1-Adamantanecarboxylic acid Organic Syntheses, Coll. Vol.
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Production of SO as a reagent in organic syntheses has centred on using compounds that "extrude" SO. Examples include the decomposition of the relatively simple molecule ethylene episulfoxide: as well as more complex examples, such as a trisulfide oxide, C10H6S3O. :C2H4SO → C2H4 \+ SO The SO molecule is thermodynamically unstable, converting initially to S2O2. SO inserts into alkenes, alkynes and dienes producing thiiranes, molecules with three-membered rings containing sulfur.
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Demoxepam is also an intermediate in the synthesis of oxazepam; it is also used in one of the syntheses of medazepam. It can be considered directly analogous/synonoymous with the synthesis of chlordiazepoxide, with the exception that instead of methylamine, hydroxide ion is the choice of base; here acid is not used for the cyclodehydration step though. Demoxepam synthesis: Reeder Earl, Sternbach Leo Henryk, (1959 to Hoffmann La Roche).
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"α-Selective Ni-Catalyzed Hydroalumination of Aryl-and Alkyl- Substituted Terminal Alkynes: Practical Syntheses of Internal Vinyl Aluminums, Halides, or Boronates." Journal of the American Chemical Society 132.32 (2010): 10961-10963. Also they observed reverse selectivity for β with Ni(PPh3)2Cl2 in their hydroalumination reactions under same conditions with little or no byproducts. The advantage of this method is that is inexpensive (and commercially available), scalable and one-pot reaction.
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Marx was invited to be the Keynote Address Speaker of the International Conference on Color Educationlecture:"The Three Fundamental Color Syntheses: Additive, Subtractive, Integration - An Experience of Meditating Color" in Aspects of Color, which was organized by the University of Art and Design in Helsinki and which showed in parallel her work in an exhibition alongside paintings by Josef Albers. Since 2000 she has been conceiving her paintings with the computer.
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Strontium sulfide is produced by roasting celestine with coke at 110–1300 °C. The sulfate is reduced, leaving the sulfide: :SrSO4 \+ 2 C → SrS + 2 CO2 About 300,000 tons are processed in this way annually. Both luminous and nonluminous sulfide phases are known, impurities, defects, and dopants being important.R. Ward, R. K. Osterheld, R. D. Rosenstein "Strontium Sulfide and Selenide Phosphors" Inorganic Syntheses, 1950, vol. III, pp. 11–24.
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Survey of Organic Syntheses Vol. I and II written by Calvin A. Buehler Buehler began his chemistry career as an undergraduate at Ohio State University where he obtained the degree of Bachelor of Chemical Engineering in 1918. Following matriculation, he was employed by The Barrett Company in Philadelphia, Pennsylvania as a research chemist. Shortly after, he returned to Ohio State University where he obtained a master's degree in 1920.
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Condensed version of efficient synthesis of Bergapten Bergapten is a natural compound coming from plants like the common fig, but it can also be synthesized. Most syntheses of linear furanocoumarins involve starting with a central aromatic unit and adding two heterocyclic rings. Alternate routes of synthesis are desirable to avoid regiochemical problems and moderate yields. The synthesis described here involves Iodine as a removable group to insure regiochemical integrity and convergence.
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Cosolvents have long been reported to be effective tools in environmental chemistry, both as powerful means of pollution remediation and as important additives in syntheses of green technologies, such as solar cells, biofuels, and sorbents. In some cases, the utilization of cosolvents also allows for satisfaction of a broad goal in the field of green chemistry: reduction in unsustainable solvent use by enhancing substrate solubility or providing greener alternatives.
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Since mannitol is found in a wide variety of natural products, including almost all plants, it can be directly extracted from natural products, rather than chemical or biological syntheses. In fact, in China, isolation from seaweed is the most common form of mannitol production. Mannitol concentrations of plant exudates can range from 20% in seaweeds to 90% in the plane tree. It is a constituent of saw palmetto (Serenoa).
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The major industrial synthesis involves the reaction of sulfur trioxide and sulfur dichloride: :SO3 \+ SCl2 → SOCl2 \+ SO2 Other methods include syntheses from phosphorus pentachloride, chlorine and sulfur dichloride, or phosgene: :SO2 \+ PCl5 → SOCl2 \+ POCl3 :SO2 \+ Cl2 \+ SCl2 → 2 SOCl2 :SO3 \+ Cl2 \+ 2 SCl2 → 3 SOCl2 :SO2 \+ COCl2 → SOCl2 \+ CO2 The first of the above four reactions also affords phosphorus oxychloride (phosphoryl chloride), which resembles thionyl chloride in many of its reactions.
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The first step in biosynthesis of these two pigments is similar, formation of a β-ring by a β-cyclase enzyme. Then the syntheses diverge, with carotene desaturase/methyltransferase enzyme transforming the β-ring end group into a χ-ring. Other reactions complete the synthesis to okenone: elongating the conjugation, adding a methoxy group, and inserting a ketone. However, only the first synthetic steps are well characterized biologically.
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Dimethyl sulfide has been used in petroleum refining to pre-sulfide hydrodesulfurization catalysts, although other disulfides or polysulfides are preferred and easier to handle. It is used as a presulfiding agent to control the formation of coke and carbon monoxide in ethylene production. DMS is also used in a range of organic syntheses, including as a reducing agent in ozonolysis reactions. It also has a use as a food flavoring component.
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In many different types of colloidal gold syntheses, the interface of the nanoparticles can display widely different character – ranging from an interface similar to a self-assembled monolayer to a disordered boundary with no repeating patterns. Beyond the Au-Ligand interface, conjugation of the interfacial ligands with various functional moieties (from small organic molecules to polymers to DNA to RNA) afford colloidal gold much of its vast functionality.
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Vulpinic acid was first isolated from lichens in 1925. As an isolated, purified substance, it is bright yellow in color. Vulpinic acid is derived biosynthetically by esterification from pulvinic acid; pulvinate itself derives from the aromatic amino acids phenylalanine and tyrosine, via dimerization and oxidative ring-cleavage of arylpyruvic acids, a process that also produces the related pulvinones. There have been several chemical syntheses reported for vulpinic acid.
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Synthesis of fatty acids is generally performed by fatty acid synthase (FAS). Though the syntheses of fatty acids are very similar across all organisms, the enzymes and subsequent enzymatic mechanisms involved in fatty acid synthesis vary between eukaryotes and prokaryotes. There are two types of fatty acid synthesis (FAS) mechanisms: type I FAS and type II FAS. Type I FAS exists in eukaryotes, including mammalian cells and fungi.
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Gertrude Maud Robinson (formerly Walsh) was an influential organic chemist most famous for her work on plant pigments; the Piloty-Robinson Pyrrole Synthesis, which is named for her; her syntheses of fatty acids; and her synthesis of δ-hexenolactone,Medawar, P.B.; Robinson, G.M.; Robinson, R. A Synthetic Differential Growth Inhibitor. Nature, 1943, 151, 195. the first synthetic molecule with the character of penicillin.Dunstan, A.E.; Woodhead, D.W.; Simonsen, J.L. Obituary notices.
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In addition he was also a specialist in Ancient Near Eastern languages, working closely with his friend François Lenormant. Babelon became a central figure in French archaeology. He sat on several important committees and was co-editor of the Gazette archéologique. His numismatic work had two focuses: on the one hand he wrote numismatic catalogues and on the other he wrote syntheses of his individual studies in comprehensive works.
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The synthesis of epoxides via this method serves as an important retrosynthetic alternative to the traditional epoxidation reactions of olefins. Johnson–Corey–Chaykovsky Reaction The reaction is most often employed for epoxidation via methylene transfer, and to this end has been used in several notable total syntheses (See Synthesis of epoxides below). Additionally detailed below are the history, mechanism, scope, and enantioselective variants of the reaction. Several reviews have been published.
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Cinchona trees remain the only economically practical source of quinine. However, under wartime pressure during World War II, research towards its synthetic production was undertaken. A formal chemical synthesis was accomplished in 1944 by American chemists R.B. Woodward and W.E. Doering. Since then, several more efficient quinine total syntheses have been achieved, but none of them can compete in economic terms with isolation of the alkaloid from natural sources.
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HPLC has many applications in both laboratory and clinical science. It is a common technique used in pharmaceutical development, as it is a dependable way to obtain and ensure product purity. While HPLC can produce extremely high quality (pure) products, it is not always the primary method used in the production of bulk drug materials. According to the European pharmacopoeia, HPLC is used in only 15.5% of syntheses.
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The structure of ajoene was determined and it was synthesized based on biosynthetic considerations in 1984, correcting an incorrect structure published in 1983. A short, scalable total synthesis of ajoene was reported in 2018 by Wirth and coworkers while a biosynthetically modeled synthesis of trifluoroajoene from difluoroallicin was published in 2017. Syntheses of various ajoene analogues have also been reported. The chemistry of ajoene has been extensively investigated.
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Bioelectrochemical reactors are a type of bioreactor where bioelectrochemical processes can take place. They are used in bioelectrochemical syntheses, environmental remediation and electrochemical energy conversion. Examples of bioelectrochemical reactors include microbial electrolysis cells, microbial fuel cells and enzymatic biofuel cells and electrolysis cells, microbial electrosynthesis cells, and biobatteries. This bioreactor is divided in two parts: The anode, where the oxidation reaction takes place; And the cathode, where the reduction occurs.
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The 1,4 isomer of dichlorobutane Dichlorobutane is a chloroalkane with the molecular formula C4H8Cl2. There are many substances encompassed under this general name (9 structural isomers, 5 of which have optical isomers). They are obtained by common synthesis methods for chloroalkanes (such as free radical chlorination of chlorobutane or nucleophilic substitution of butanediols, depending on the desired isomer). Dichlorobutane isomers are further utilized in various industrial and laboratory organic syntheses.
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N-Methylformamide (NMF) is a colorless, nearly odorless, organic compound with molecular formula CH3NHCHO, which is a liquid at room temperature. NMF is mainly used as a reagent in various organic syntheses with limited applications as a highly polar solvent. NMF is closely related to other formamides, notably formamide and dimethylformamide (DMF). However, industrial use and production of NMF are far less than for either of these other formamides.
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Franz undertook research in many areas during his time at Monsanto. Some of his other chemistry research includes antiauxin chemistry (isothiazoles, isoxazoles, pyrazoles), plant chemistry, cell membrane chemistry (glyceride and phospholipid syntheses, liposomes), plant hormone chemistry (abscissic acid analogs, ethylene generators), and nitride sulfide chemistry. He also performed research pertaining to reaction mechanisms, coenzyme A antimetabolites, biorational design of herbicides, and periselective addition reactions of one- and threedipoles, as well as fundamental organic research.
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There are two forms or enantiomers of aspartic acid. The name "aspartic acid" can refer to either enantiomer or a mixture of two.. Of these two forms, only one, "L-aspartic acid", is directly incorporated into proteins. The biological roles of its counterpart, "D-aspartic acid" are more limited. Where enzymatic synthesis will produce one or the other, most chemical syntheses will produce both forms, "DL-aspartic acid", known as a racemic mixture.
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Of the several syntheses of DCC, Pri-Bara et al. use palladium acetate, iodine, and oxygen to couple cyclohexyl amine and cyclohexyl isocyanide. Yields of up to 67% have been achieved using this route: : C6H11NC + C6H11NH2 \+ O2 → (C6H11N)2C + H2O Tang et al. condense two isocyanates using the catalyst OP(MeNCH2CH2)3N in yields of 92%: :Homogeneous catalysis DCC has also been prepared from dicyclohexylurea using a phase transfer catalyst by Jaszay et al.
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Triphenylmethyl hexafluorophosphate readily hydrolyzes, in a reaction that is the reverse of one of its syntheses: :(C6H5)3CPF6 \+ H2O → (C6H5)3COH + HPF6 Triphenylmethyl hexafluorophosphate has been used for abstracting hydride () from organic compounds. Treatment of metal-alkene and diene complexes one can generate allyl and pentadienyl complexes, respectively. Triphenylmethyl perchlorate is a common substitute for triphenylmethyl hexafluorophosphate. However, the perchlorate is not used as widely, because, like other organic perchlorates, it is potentially explosive.
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It also finds use as a lubricant and a plasticizer. Louis Bouveault used ethyl oleate to demonstrate Bouveault–Blanc reduction, producing oleyl alcohol and ethanol, a method which was subsequently refined and published in Organic Syntheses. Ethyl oleate is regulated as a food additive by the Food and Drug Administration under "Food Additives Permitted for Direct Addition to Food for Human Consumption", 21CFR172.515. Ethyl oleate has been identified as a primer pheromone in honeybees.
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Quadricyclane, a valence isomer, can be obtained from norbornadiene by a photochemical reaction when assisted by a sensitizer such as acetophenone: :300px The norbornadiene-quadricyclane couple is of potential interest for solar energy storage when controlled release of the strain energy stored in quadricyclane back to norbornadiene is made possible. Norbornadiene is reactive in cycloaddition reactions. Norbornadiene is also the starting material for the synthesis of diamantaneDiamantane in Organic Syntheses Coll. Vol. 6, p.
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The biosynthesis of ginkgolide B While researchers have published chemical pathways to make this molecule, most of the designed syntheses were too complex and produced little of the actual material to run full analyses. Therefore, studying the biosynthesis of the molecule is preferable. Most of the natural product terpenoids start with isopentenyl diphosphate synthesized by the MEP pathway. This pathway also generates dimethylallyl diphosphate, from pyruvate and D-glyercaldehyde 3-phosphate (GAP).
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Many scholars began producing syntheses and reworkings of the commentaries of the Alexandrian scholars of previous centuries, at the expense of their own originalities. Other scholars branched out and began writing commentaries on the poetic works of postclassical authors, including Alexandrian poets such as Callimachus and Apollonius of Rhodes. Meanwhile, Alexandrian scholarship was probably introduced to Rome in the first century BC by Tyrannion of Amisus ( 100– 25 BC), a student of Dionysius Thrax.
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Dr. Shulgin, a former research chemist at the Dow Chemical Company, re-discovered the synthesis for MDMA in 1976 and published the syntheses for more than 200 phenethylamine compounds of his own invention, and 55 tryptamine compounds many of which were also his own invention. The Shulgins were motivated to release the synthesis information as a way to protect the public's access to information about psychedelic compounds, a goal Alexander Shulgin has noted many times.
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1985, 107, 1448-1449. doi 10.1021/ja00291a077Curran, D. P.; Rakiewicz, D. M., “Radical-initiated polyolefinic cyclizations in linear triquinane synthesis. Model studies and total synthesis of hirsutene” Tetrahedron 1985, 41, 3943-3958. doi 10.1016/S0040-4020(01)97175-3 the first of many such syntheses with cascade radical reactions, is today regarded as a classic.Nicolaou, K. C.; Sorenson, E. J., Classics in Total Synthesis, VCH: Weinheim, 1995; Ch 23, pp 381-420, “Hirstutene and Capnellene”.
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When Woodward accomplished this feat, organic synthesis was still largely a matter of trial and error, and nobody thought that such complex structures could actually be constructed. Woodward showed that organic synthesis could be made into a rational science, and that synthesis could be aided by well-established principles of reactivity and structure. This synthesis was the first one in a series of exceedingly complicated and elegant syntheses that he would undertake.
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Chloroethyl chloroformates (chemical formula: C3H4Cl2O2) are a pair of related chemical compounds. They can be used to form protecting groups and as N-dealkylating agents.'A new reagent for the selective, high-yield N-dealkylation of tertiary amines: improved syntheses of naltrexone and nalbuphine' R. A. Olofson, Jonathan T. Martz, Jean Pierre Senet, Marc Piteau, Thierry Malfroot J. Org. Chem., 1984, 49 (11), pp 2081–2082 They are listed as extremely hazardous substances.
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The trihydrate salt is obtained as a reddish-brown precipitate by adding potassium cyanide to a cobalt salt solution.:John H. Bigelow, "Potassium Hexacyanocobaltate(III)" Inorganic Syntheses, 1946, Volume I1, p. 225. :CoCl2(H2O)6 \+ 2 KCN → Co(CN)2 \+ 2 KCl + 6 H2O Hydrated Co(CN)2 dissolves in the presence of excess potassium cyanide, forming a red solution of K4Co(CN)6. This material further oxidizes to yellow K3Co(CN)6.
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For more complex molecules, a convergent synthetic approach may be preferable, one that involves individual preparation of several "pieces" (key intermediates), which are then combined to form the desired product. Convergent synthesis has the advantage of generating higher yield, compared to linear synthesis. Robert Burns Woodward, who received the 1965 Nobel Prize for Chemistry for several total syntheses (e.g., his 1954 synthesis of strychnine), is regarded as the father of modern organic synthesis.
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Organomercury compounds are versatile synthetic intermediates due to the well controlled conditions under which they undergo cleavage of the Hg-C bonds. Diphenylmercury is a source of the phenyl radical in certain syntheses. Treatment with aluminium gives triphenyl aluminium: :3 Ph2Hg + 2 Al -> (AlPh3)2 \+ 3 Hg As indicated above, organomercury compounds react with halogens to give the corresponding organic halide. Organomercurials are commonly used in transmetalation reactions with lanthanides and alkaline-earth metals.
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He investigated the stability of radicals on trivalent carbons leading him to study organometallic compounds and their application in his research. He also worked on the syntheses of multi-membered ring systems. including the Nobel Lecture, December 12, 1963 Consequences and Development of an Invention In 1933 Ziegler published his first major work on large ring systems, "Vielgliedrige Ringsysteme" which presented the fundamentals for the Ruggli-Ziegler dilution principle. Max Planck Institute for Coal Research.
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Barium ferrate is an oxidizing agent and is used as an oxidizing reagent in organic syntheses. Its other applications include removal of color, removal of cyanide, killing bacteria and contaminated and waste water treatment. Salts of ferrate (VI) are energetic cathode materials in “super-iron” batteries. Cathodes containing ferrate (VI) compounds are referred to as “super-iron” cathodes due to their highly oxidized iron basis, multiple electron transfer, and high intrinsic energy.
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Stoddart has developed highly efficient syntheses of mechanically-interlocked molecular architectures such as molecular Borromean rings, catenanes and rotaxanes utilising molecular recognition and molecular self-assembly processes. He has demonstrated that these topologies can be employed as molecular switches.A. Coskun, M. Banaszak, R. D. Astumian, J. F. Stoddart, B. A. Grzybowski, Chem. Soc. Rev., 2012, 41, 19–30 His group has even applied these structures in the fabrication of nanoelectronic devices and nanoelectromechanical systems (NEMS).
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He decided to join the M.I.T. faculty as an assistant professor at a salary that was half of what he made at Merck. Within his first few years at M.I.T., John Sheehan was already recognized for his ingenuity in synthetic organic chemistry, especially for his new methods of synthesis of peptides, three new syntheses of β-lactams, first synthesis of the penicillin ring system, and his work on several other natural products.
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Some of this control originates from the reaction of CTAB with other reagents in the gold nanoparticle synthesis. For example, in aqueous gold nanoparticle syntheses, chlorauric acid (HAuCl4) may react with CTAB to create a CTA+-AuCl complex. The gold complex is then reacted with ascorbic acid to produce hydrochloric acid, an ascorbic acid radical, and CTA-AuCl3. The ascorbic acid radical and CTA-AuCl3 react spontaneously to create metallic Au0 nanoparticles and other byproducts.
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The works display their form language in relation to point and line, surface and depth, black and white, surfaces and forms, rhythm, fire, erosion, and light and shadow.Nafas Art Magazine, January 2008, Alexandra von Stosch: Ali Kaaf. Dramaturgy of Signs Kaaf’s abstractions are the result of his intense dealings with script, architecture, and history. Kaaf’s works engage in dialogue with cultures and disciplines and, beyond them, through interdisciplinary collaborations, to Gesamtkunstwerke, syntheses of the arts.
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Metabolic activation of the nitrosamine NDMA, involving its conversion to an alkylating agent The organic chemistry of nitrosamines is well developed with regard to their syntheses, their structures, and their reactions. They are usually produced by the reaction of nitrous acid (HNO2) and secondary amines. :HONO + R2NH → R2N-NO + H2O The nitrous acid usually arises from protonation of nitrite. This synthesis method is relevant to the generation of nitrosamines under some biological conditions.
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Rhenium trioxide can be formed by reducing rhenium(VII) oxide with carbon monoxide at 200 °C or elemental rhenium at 400 °C . H. Nechamkin, C. F. Hiskey, "Rhenium(VI): Oxide (Rhenium Trioxide)" Inorganic Syntheses, 1950 Volume 3, pp. 186-188. :Re2O7 \+ CO → 2 ReO3 \+ CO2 :3 Re2O7 \+ Re → 7 ReO3 Re2O7 can also be reduced with dioxane. Rhenium trioxide crystallizes with a primitive cubic unit cell, with a lattice parameter of 3.742 Å (374.2 pm).
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The Hofmann rearrangement is a decarbonylation reaction whereby an amide is converted to an amine by way of an isocyanate intermediate. It is usually carried out under strongly basic conditions. ::500px The reaction can also be carried out under mildly acidic conditions by way of the same intermediate using a hypervalent iodine compound in aqueous solution. An example published in Organic Syntheses is the conversion of cyclobutanecarboxamide, easily synthesized from cyclobutylcarboxylic acid, to cyclobutylamine.
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Chloro(cyclopentadienyl)bis(triphenylphosphine)ruthenium was first reported in 1969 when it was prepared by reacting dichlorotris(triphenylphosphine)ruthenium(II) with cyclopentadiene. :RuCl2(PPh3)3 \+ C5H6 → RuCl(PPh3)3(C5H5) + HCl It is prepared by heating a mixture of ruthenium(III) chloride, triphenylphosphine, and cyclopentadiene in ethanol.Bruce, M. I.; Hamiester, C., Swincer, A. G., Wallis, R. C. "Some η5-Cyclopentadienylruthenium(II) Complexes Containing Triphenylphosphine" Inorganic Syntheses 1982, volume 21, pp 78-82.
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A. M. Mueting, B. D. Alexander, P. D. Boyle, A. L. Casalnuovo, L. N. Ito, B. J. Johnson, L. H. Pignolet "Mixed-Metal-Gold Phosphine Cluster Compounds" Inorganic Syntheses, 1992, Volume 29, Pages 279–298, 2007. As shown in the scheme below, the methyl complex Ph3PAuMe is prepared from triphenylphosphinegold(I) chloride by transmetalation with a Grignard reagent. Further treatment of Ph3PAuMe with methyllithium displaces the phosphine ligand and generates lithium dimethylaurate, Li+[AuMe2]–.
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Ugi's first report of the synthesis of [1-(dimethylamino)ethyl]-ferrocene. Since the original report, other syntheses of Ugi’s amine have been reported. These are generally directed towards the synthesis of only one of the enantiomers rather than a racemic mixture. An enzymatic resolution of (±)1-ferrocenylethanol can be performed by Pseudomonas Fluorescens lipase-mediated acylation with vinyl acetate, providing unreacted (1S)-1-ferrocenylethanol (92% ee) and (1R)-[1-(acetyloxy)ethyl]-ferrocene (96% ee).
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NiF2 is prepared by treatment of anhydrous nickel(II) chloride with fluorine at 350 °C:Priest, H. F. “Anhydrous Metal Fluorides” Inorganic Syntheses McGraw-Hill: New York, 1950; Vol. 3, pages 171-183. :NiCl2 \+ F2 -> NiF2 \+ Cl2 The corresponding reaction of cobalt(II) chloride results in oxidation of the cobalt, whereas nickel remains in the +2 oxidation state after fluorination because its +3 oxidation state is less stable. Chloride is more easily oxidized than nickel(II).
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Laboratory synthesis of ICZs has been a topic of great interest since their discovery. Unfortunately, due to the somewhat complex nature of the molecule and the high level of reactivity of carbons on indole molecules, a facile high yield synthesis has yet to be found. Despite this, there have been many ways found to produce this compound in its various forms. Of special interest is one of the better REB syntheses, found in 1999.
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Non-basic tendencies in organocerium reagents The oxophilicity of cerium imparts strong 1,2-selectivity in reactions with conjugated electrophiles similarly to organolithium reagents. At the same time, organocerium reagents can be used to synthesize ketones from acyl compounds without over-addition, as seen with organocuprates. This dichotomy illustrates the unique reactivity of organolanthanide reagents. Reactivity and selectivity of organocerium compounds Finally, organocerium reagents have been employed in a number of total syntheses.
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This was one of the first syntheses, where the molybdate is reduced at the same time as the cyanometalate is formed. The yield is typically about 70%. This method is applicable to big batches, because the work-up is more efficient at large scale and the starting materials are inexpensive. 4 MoO42- \+ 32 CN- \+ BH4- \+ 31 H+ → 4 [Mo(CN)8]4- \+ 16 H2O + H3BO3 Molybdenum has a high affinity towards oxygen.
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Molecular GeCl2 is often called dichlorogermylene, highlighting its resemblance to a carbene. The structure of gas-phase molecular GeCl2 shows that it is a bent molecule, as predicted by VSEPR theory. The dioxane complex, GeCl2·dioxane, has been used as a source of molecular GeCl2 for reaction syntheses, as has the in situ reaction of GeCl4 and Ge metal. GeCl2 is quite reactive and inserts into many different types of chemical bonds.
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Erich Clar (23 August 1902 in Hřensko – 27 March 1987 in Estepona) was a German organic chemist who studied polycyclic aromatic hydrocarbon chemistry. He is considered as the father of that field. He authored the two-volume Polycyclic Hydrocarbons, which described the syntheses, properties, and UV- visible absorption spectra of hundreds of PAHs. He created the Sextet Theory, now eponymously called Clar's rule, to describe the behavior of polycyclic aromatic hydrocarbon isomers.
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Efforts to develop water-soluble and "green" total syntheses are also being explored, with the first of these methods implementing polyethylenimine (PEI)-coated nanoparticles. Thermal decomposition uses high temperature solvents to decompose molecular precursors into nuclei, which grow at roughly the same rate, yielding high quality, monodisperse NPs. Growth is guided by precursor decomposition kinetics and Oswald ripening, allowing for fine control over particle size, shape and structure by temperature and reactant addition and identity.
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Glick's work falls within two broad areas. As a medievalist, he is best seen as a historian of technology but has also written interesting syntheses of medieval science, from a comparative perspective. As a historian of modern science he has concentrated on the reception of strong paradigms—Darwinism, psychoanalysis, and relativity—in the Iberian world. In both areas, he is a comparativist and has commented from time to time on methodological and historiographical approaches.
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One of the principal methods for alkene synthesis in the laboratory is the room elimination of alkyl halides, alcohols, and similar compounds. Most common is the β-elimination via the E2 or E1 mechanism, but α-eliminations are also known. The E2 mechanism provides a more reliable β-elimination method than E1 for most alkene syntheses. Most E2 eliminations start with an alkyl halide or alkyl sulfonate ester (such as a tosylate or triflate).
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In order to achieve this quality, a situation is to be structurally understood and structurally transformed during the working process. According to this systematic approach, landscape architecture and design are worked on as concepts and not as decoration. The necessary syntheses of ecology and of “healthy living conditions” - for the human and for nature – are integrated parts of these spatial concept-findings, considered as the basis for intervening into ‘nature by culture’.
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Sodium azide gives the benzimidazolone via the isocyanate. Isatoic anhydride is used as a blowing agent in the polymer industry, an application that exploits its tendency to release CO2. Isatoic anhydride has also been reported to be used as a precursor for the synthesis of methaqualone and related 4-quinazolinone based pharmaceutical drugs.A survey of reported syntheses of methaqualone and some positional and structural isomers Etienne F. van Zyl Forens. Sci. Int.
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105 °C). TFA is popularly used as a strong acid to remove t-butyl derived side-chain protecting groups in Fmoc peptide synthesis, and in other organic syntheses to remove the t-butoxycarbonyl protecting group. At a low concentration, TFA is used as an ion pairing agent in liquid chromatography (HPLC) of organic compounds, particularly peptides and small proteins. TFA is a versatile solvent for NMR spectroscopy (for materials stable in acid).
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For example, cholesterol-related compounds have opened ways to synthesize complex human hormones and their modified derivatives. Since the start of the 20th century, complexity of total syntheses has been increased to include molecules of high complexity such as lysergic acid and vitamin B12. The total synthesis of vitamin B12 marked a major achievement in organic chemistry. The discovery of petroleum and the development of the petrochemical industry spurred the development of organic chemistry.
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Complex compounds can have tens of reaction steps that sequentially build the desired molecule. The synthesis proceeds by utilizing the reactivity of the functional groups in the molecule. For example, a carbonyl compound can be used as a nucleophile by converting it into an enolate, or as an electrophile; the combination of the two is called the aldol reaction. Designing practically useful syntheses always requires conducting the actual synthesis in the laboratory.
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Tetrahydrobiopterin (BH4, THB), also known as sapropterin (INN), is a cofactor of the three aromatic amino acid hydroxylase enzymes, used in the degradation of amino acid phenylalanine and in the biosynthesis of the neurotransmitters serotonin (5-hydroxytryptamine, 5-HT), melatonin, dopamine, norepinephrine (noradrenaline), epinephrine (adrenaline), and is a cofactor for the production of nitric oxide (NO) by the nitric oxide syntheses. Chemically, its structure is that of a (dihydropteridine reductase) reduced pteridine derivative (Quinonoid dihydrobiopterin).
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Miller continued his research until his death in 2007. As the knowledge on early atmosphere progressed, and techniques for chemical analyses advanced, he kept on refining the details and methods. He not only succeeded in synthesising more and more varieties of amino acids, he also produced a wide variety of inorganic and organic compounds essential for cellular construction and metabolism. In support, a number of independent researchers also confirmed the range of chemical syntheses.
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It can be produced by reduction of the hexafluoride with carbon monoxide at elevated temperatures.Gordon W. Halstead, P. Gary Eller "Uranium(V) Fluorides and Alkoxides" Inorganic Syntheses 1982, volume 21, 162. : 2 UF6 \+ CO → 2 UF5 \+ COF2 Other reducing agents have been examined. The α form is a linear coordination polymer consisting of chains of octahedral uranium centers in which one of the five fluoride anion forms a bridge to the next uranium atom.
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The Wieland–Miescher ketone is the Robinson annulation product of 2-methyl-cyclohexane-1,3-dione and methyl vinyl ketone. This compound is used in the syntheses of many steroids possessing important biological properties and can be made enantiopure using proline catalysis. Wieland–Miescher ketone F. Dean Toste and co-workers have used Robinson annulation in the total synthesis of (+)-fawcettimine, a tetracyclic Lycopodium alkaloid that has potential application to inhibiting the acetylcholine esterase.
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NaO2 is prepared by treating sodium peroxide with oxygen at high pressures:Stephen E. Stephanou, Edgar J. Seyb Jr., Jacob Kleinberg "Sodium Superoxide" Inorganic Syntheses 1953; Vol. 4, 82-85. :Na2O2 \+ O2 → 2 NaO2 It can also be prepared by careful oxygenation of a solution of sodium in ammonia: :Na(in NH3) + O2 → NaO2 It is also produced, along with sodium peroxide, when sodium is stored under inappropriate conditions (e.g. in dirty or partially halogenated solvents).
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Many methods, have been devised for synthetically producing ACC since its discovery at 1989, however, only few syntheses successfully stabilized ACC for more than several weeks. The best effective method to stabilize ACC lifetime is by forming it in the presence of magnesium and/or phosphorus. Also, ACC crystallisation pathways have been observed to depend on its Mg/Ca ratio, transforming to aragonite, Mg-calcite, monohydrocalcite or dolomite with increasing Mg content. Huang et al.
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Silver subfluoride is the inorganic compound with the formula Ag2F. This is an unusual example of a compound where the oxidation state of silver is fractional. The compound is produced by the reaction of silver and silver(I) fluoride:Lee Poyer, Maurice Fielder, Hugh Harrison, Burl E. Bryant "Disilver Fluoride: (Silver “Subfluoride”)" Inorganic Syntheses, 1957, Volume 5, 92–94. :Ag + AgF → Ag2F It forms small crystals with a bronze reflex and is a good conductor of electricity.
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The ends of the struts are designed to fit in the holes of the connector nodes, allowing for syntheses of a variety of structures. The idea of shape-coding the three types of struts was developed by Marc Pelletier and Paul Hildebrandt. To create the "balls," or nodes, Pelletier and Hildebrandt invented a system of 62 hydraulic pins that came together to form a mold. The first connector node emerged from their mold perfectly on April 1, 1992.
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Compendium of Chemical Terminology (IUPAC "Gold Book") functional group This allows for systematic prediction of chemical reactions and behavior of chemical compounds and design of chemical syntheses. Furthermore, the reactivity of a functional group can be modified by other functional groups nearby. In organic synthesis, functional group interconversion is one of the basic types of transformations. Functional groups are groups of one or more atoms of distinctive chemical properties no matter what they are attached to.
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Multiple syntheses of phantasmidine have been proposed, some of which have been included below. The general mechanism for the synthesis of phantasmidine is shown below. General Synthesis of Phantasmidine In the general reaction mechanism, 1,2-bis(trimethylsilyloxy)cyclobutene is reacted with the intermediate to form the second product in 85% yield. This is then run under basic conditions to produce an intramolecular aldol reaction followed by an intramolecular nucleophilic aromatic substitution, leading to the lactam product in 46% yield.
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Since the 1960s, Christe has been investigating the synthesis of new fluorides of nitrogen, halogen, and the halogen oxides, as well as their ions. Notable examples are the syntheses of both NF4+ and ClF6+. On the occasion of the 100th anniversary of Henri Moissan's first production of fluorine, Christe in 1986 reported about the first truly chemical synthesis of fluorine. Another important field of his work covers the research on homoleptic nitrogen compounds for use in energetic materials.
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His work also involved the exhaustive use of the then newly developed techniques of infrared spectroscopy and later, nuclear magnetic resonance spectroscopy. Another important feature of Woodward's syntheses was their attention to stereochemistry or the particular configuration of molecules in three-dimensional space. Most natural products of medicinal importance are effective, for example as drugs, only when they possess a specific stereochemistry. This creates the demand for 'stereoselective synthesis', producing a compound with a defined stereochemistry.
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According to Niemeyer, the dual poles of nature and art are not only the basis of his experience but at the time also his central theme. His main interest is the perception of space, time, distances and proportion and forms the synthesis between art and nature which implies in the end a dialogue between man and nature. He considers land-art a kind of laboratory, a ground for experiments for aesthetic-artistic, political and ecological syntheses.
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Acid-base extraction is a procedure using sequential liquid–liquid extractions to purify acids and bases from mixtures based on their chemical properties. Acid-base extraction is routinely performed during the work-up after chemical syntheses and for the isolation of compounds and natural products like alkaloids from crude extracts. The product is largely free of neutral and acidic or basic impurities. It is not possible to separate chemically similar acids or bases using this simple method.
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While syntheses of pentacyclic triterpenoids in general have been proven challenging, partial synthesis of 11,12-α-oxidotaraxerol, an epoxide taraxerene derivative, has been reported by Ursprung et al. from α- and β-amyrin. Exposing an ethanolic solution of α- and β-amyrin in summer sunlight for 12 weeks yields a colorless precipitate, and saponification of the precipitate gives 11,12-α-oxidotaraxerol. Alternatively, the process could be accelerated by exposing ethanolic β-amyrin solution under ultraviolet light.
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Mary and Carl worked together as a team, with Mary specializing as an analytical chemist. The Hills used Grignard reagents to develop chemical syntheses of ketenes, which was funded by grants from the National Science Foundation (NSF) and the U.S. Air Force. Mary Hill developed the analytical methods for the work, and specialized using monomeric ketenes. She utilized spectroscopic methods, including ultraviolet spectophotometry in her studies and worked to develop analytical methods to track the progress of chemical reactions.
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The basic procedures were often obtained from textbooks, and the procedures were sketchy. Reproducibility was important in summer preps, so students were required to keep meticulous record books. The procedures were finally collected and published for the first time in a four- pamphlet set called Organic Chemical Reagents, which quickly sold out. The publishers received submissions from other chemists, which spawned the idea for serial publication, and the first annual volume of Organic Syntheses was thus published in 1921.
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Xenic acid is a noble gas compound formed by the dissolution of xenon trioxide in water. Its chemical formula is H2XeO4. It is a very powerful oxidizing agent, and its decomposition is dangerous as it liberates a large amount of gaseous products: xenon, oxygen, and ozone. However, this feature is also what makes xenic acid practically useful in syntheses: there is no chance of introducing impurities to the oxidation products, as all the byproducts can be trivially evaporated.
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Nicotinamide adenine dinucleotide phosphate, abbreviated NADP or, in older notation, TPN (triphosphopyridine nucleotide), is a cofactor used in anabolic reactions, such as the Calvin cycle and lipid and nucleic acid syntheses, which require NADPH as a reducing agent. It is used by all forms of cellular life. NADPH is the reduced form of NADP. NADP differs from NAD by the presence of an additional phosphate group on the 2' position of the ribose ring that carries the adenine moiety.
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Illustration to Milton a Poem. In Blake's mythology, Adam and Satan are two extremes of the fallen Albion. There are twelve plates in each of the Paradise Lost sets, one for each of the books in the poem. While some of these, such as Satan, Sin and Death: Satan Comes to the Gates of Hell, depict specific scenes from the epic; others, such as Satan Watching the Endearments of Adam and Eve, are syntheses of several scenes.
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The silyl group is a non-polar and relatively unreactive species and is therefore tolerant of many reagents and reaction conditions that might be incompatible with free alcohols. Consequently, the silyl group also eliminates the need for introduction of hydroxyl protecting groups. In short, by deferring introduction of an alcohol to a late synthetic stage, opting instead to carry through a silane, a number of potential problems experienced in total syntheses can be mitigated or avoided entirely.
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In molecular biology, S4 domain refers to a small RNA-binding protein domain found in a ribosomal protein named S4. The S4 domain is approximately 60-65 amino acid residues long, occurs in a single copy at various positions in different proteins and was originally found in pseudouridine syntheses, a bacterial ribosome-associated protein. The S4 protein helps to initiate assembly of the 16S rRNA. In this way proteins serve to organise and stabilise the rRNA tertiary structure.
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Liquid-based syntheses are efficient and typically better for the environment. The simplest and most economical method, in which components of the nanocrystal are mixed together in solution and allowed to precipitate. This method yields nanoparticles with a narrow size distribution (around 100 nm), but that lack the precision of more intricate methods, thereby requiring more post-synthesis work up. NPs can be improved with an annealing step at high temperatures, but this often leads to aggregation, limiting applications.
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Anderson's wide-ranging research resulted in hundreds of published papers in the fields of planetary science, seismology, mineral physics, petrology, geochemistry, tectonics and the philosophy of science. He continued to work and publish until his death. His widely known textbooks, Theory of the Earth, and New Theory of the Earth are regarded by colleagues as compelling syntheses of the origins of the Earth and its inner workings by one of the great geophysical authorities of our time.
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In 1875 after returning to Harvard Jackson synthesized the first new organic compound made in a Harvard laboratory, p-bromobenzyl bromide. This provided a method of producing substituted benzyl compounds with interesting results, such as a synthesis of anthracene. In the following years he developed syntheses of flavoring compounds curcumin and vanillin. He also synthesised benzine tri- sulfonic acid and developed what is now a traditional method of nitrating organic materials, preliminary sulfonation followed by nitration.
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In practice, when an antithesis is selected to suit the user's subjective purpose, the resulting "contradictions" are rhetorical, not logical, and the resulting synthesis is not rigorously defensible against a multitude of other possible syntheses. The problem with the Fichtean "thesis–antithesis–synthesis" model is that it implies that contradictions or negations come from outside of things. Hegel's point is that they are inherent in and internal to things. This conception of dialectics derives ultimately from Heraclitus.
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117 (21), 5855-5856. . frameless The ring strain in 8-11 atom rings has proven to be challenging for RCM; however, there are many cases where these cyclic systems have been synthesized. In 1997, Fürstner reported a facile synthesis to access jasmine ketolactone (E/Z) through a final RCM step. At the time, no previous 10-membered ring had been formed through RCM, and previous syntheses were often lengthy, involving a macrolactonization to form the decanolide.
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Taxodone rearranges easily in the presence of mild acids and reacts readily with nucleophiles. Although taxodone shows higher anticancer and antibacterial activity than taxodione it eluded creation in the laboratory for over 25 years because of its inherent instability. During this time several different groups reported syntheses of the more stable taxodione. In 1993 taxodone was synthesized for the first time in a 16 step sequence utilizing a unique phenol benzylic epoxide electron reorganization in the final step.
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The reactions of the compounds containing xenon are mostly conducted in hydrogen fluoride or bromine pentafluoride, which dissolve readily both xenon difluorides and its multiple derivatives,Pointner BE, Suontamo RJ, Schrobilgen GJ. Syntheses and X-ray crystal structures of alpha- and beta-, , , and and computational studies of the and cations and related species. Inorg Chem. 2006 Feb 20;45(4):1517-34. although sulfuric solvents are also used sometimes, in particular sulfuryl chloride fluoride for strong oxidants.
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Chalcones can be prepared by an aldol condensation between benzaldehyde and acetophenone in the presence of sodium hydroxide as a catalyst. :preparation of chalcone This reaction can be carried out without any solvent as a solid- state reaction. The reaction between substituted benzaldehydes and acetophenones can be used as an example of green chemistry in undergraduate education. In a study investigating green syntheses, chalcones were synthesized from the same starting materials in high-temperature water (200 to 350 °C).
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Oracc currently includes several different kinds of projects. Some gather and present historical information for studying certain areas of ancient Near Eastern life or scholarship, including projects designed to contextualize specific textual corpora ("portals"). Others provide interfaces for searching corpora. These usually incorporate full transliterations and translations of texts in a given corpus, and many offer supplementary material such as an introduction to the corpus, discussion of its historical context, and interpretive syntheses of its content.
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Bromopentafluorobenzene is an organofluorine compound with the formula C6F5Br. It is a colorless liquid that is used to prepare pentafluophenyl compounds. These syntheses typically proceed via the intermediacy of C6F5Li or the Grignard reagent. Illustrative is preparation of tris(pentafluorophenyl)borane:Piers, W. E.; Chivers, T. “Pentafluorophenylboranes: from Obscurity to Applications”, Chemical Society Reviews, 1997, 26, 345-354. :3 C6F5MgBr + BCl3 → (C6F5)3B + 3 MgBrCl Other derivatives include LiB(C6F5)4, [CuC6F5]4, and Ni(C6F5)2(dioxane)2.
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PAHs are uncharged, non-polar molecules, with distinctive properties due in part to the delocalized electrons in their the aromatic rings. Many of them are found in coal and in oil deposits, and are also produced by the thermal decomposition of organic matter—for example, in engines and incinerators or when biomass burns in forest fires. Polycyclic aromatic hydrocarbons are discussed as possible starting materials for abiotic syntheses of materials required by the earliest forms of life.
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Depending on the climatic conditions affecting crop yields, consumption and prices of agrochemicals are subject to wide fluctuations from year to year, impacting also the suppliers. The molecular structures of modern agrochemicals are much more complex than in older products, but lower than of their pharma counterparts. The average molecular weight of the top 10 is 330, as compared with 477 for the top 10. In comparison to reagents used in pharmaceutical fine chemical syntheses, hazardous chemicals, e.g.
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Epoxidation of cis- and trans-olefins yield epothilone A and its analogues. One of total syntheses of epothilone B is outlined below and was described by the laboratory of K. C. Nicolaou. The retrosynthetic analysis revealed 1, 2, and 3 as the building blocks (Figure 1). Figure 1 As seen in Figure 2, keto acid 1 was generated from the keto aldehyde that was converted to the silyl ether via asymmetric allylboration and silylation of the resulting alcohol.
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The molecule is tetrahedral with C2v symmetry. The S-O distance is 140.5 pm, S-F is 153.0 pm. As predicted by VSEPR, the O-S-O angle is more open than the F-S-F angle, 124° and 97°, respectively. One synthesis begins with the preparation of potassium fluorosulfite:Seel, F. "Potassium Fluorosulfite" Inorganic Syntheses 1967, IX, pages 113-115. . :SO2 \+ KF → KSO2F This salt is then chlorinated to give sulfuryl chloride fluoride: :KSO2F + Cl2 → SO2ClF + KCl Further heating at 180 °C of potassium fluorosulfite with the sulfuryl chloride fluoride gives the desired product:Seel, F. "Sulfuryl Chloride Fluoride and Sulfuryl Fluoride" Inorganic Syntheses 1967, vol. IX, pages 111-113. :SO2ClF + KSO2F → SO2F2 \+ KCl + SO2 Heating metal fluorosulfonate salts also gives this molecule: :Ba(OSO2F)2 → BaSO4 \+ SO2F2 It can be prepared by direct reaction of fluorine with sulfur dioxide: :SO2 \+ F2 → SO2F2 On a laboratory scale, sulfuryl fluoride has been conveniently prepared from 1,1'-sulfonyldiimidazole, in the presence of potassium fluoride and acid. Sulfuryl fluoride is unreactive toward molten sodium metal.
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This synthesis took a total of 31 steps and proceeded in 0.06% overall yield. The hydrocodone synthesis of Kenner C. Rice is one of the most efficient and proceeds in 30% overall yield in 14 steps. At 9 steps, the Barriault route is the shortest to date, but contains a number of low-yielding steps. Several other syntheses were reported, notably by the research groups of Evans, Fuchs, Parker, Overman, Mulzer-Trauner, White, Taber, Trost, Fukuyama, Guillou, Stork, Magnus, Smith, and Barriault.
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In the absence of donor ligand, lithium cation is closely coordinated to the oxygen atom, however, when the lithium cation is solvated by HMPA, the coordination between carbonyl oxygen and lithium ion is weakened. This method generally cannot be used to affect the regioselectivity of alkyl- and aryllithium reagents. :1,4vs1,2 addition Organolithium reagents can also perform enantioselective nucleophilic addition to carbonyl and its derivatives, often in the presence of chiral ligands. This reactivity is widely applied in the industrial syntheses of pharmaceutical compounds.
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Irwin Kremen (June 5, 1925 – February 5, 2020) was an American artist who began making art while Director of the Duke University Graduate Program in Clinical Psychology, when he was 41, after earning a PhD six years earlier in clinical psychology at Harvard University. Kremen's artwork mainly consists of non-representational collage, sculpture, and painting. In his later years he defined a fourth grouping which he called "multimodes." These are syntheses of the other three or sometimes of just two.
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The challenge that aconitine poses to synthetic organic chemists is due to both the intricate interlocking hexacyclic ring system that make up its core and the elaborate collection of oxygenated functional groups at its periphery. A handful of simpler members of the aconitine alkaloids, however, have been prepared synthetically. In 1971, the Weisner group discovered the total synthesis of talatisamine (a C19-norditerpenoid). In the subsequent years, they also discovered the total syntheses of other C19-norditerpenoids, such as chasmanine, and 13-deoxydelphonine.
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Several syntheses of racemic N-methylphenylethanolamine have been published over the years. A synthesis using "classical" methodology was reported by Durden and co-workers, starting from acetophenone. The methyl group of acetophenone was brominated with bromine to give α-bromoacetophenone, which was then reacted with N-methylbenzylamine to give an amino-ketone. The amino-ketone was reduced with lithium aluminum hydride to the corresponding amino-alcohol, and the N-benzyl group finally removed by catalytic hydrogenation using a palladium on charcoal catalyst.
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Separate sets of CesA genes are involved in primary and secondary cell wall biosynthesis. There are known to be about seven subfamilies in the plant CesA superfamily, some of which include the more cryptic, tentatively-named Csl (cellulose synthase-like) enzymes. These cellulose syntheses use UDP-glucose to form the β(1→4)-linked cellulose. Bacterial cellulose is produced using the same family of proteins, although the gene is called BcsA for "bacterial cellulose synthase" or CelA for "cellulose" in many instances.
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It produces small stone fruits, Cocculus indicus, which are typically dried. Currently, there are as many as five total syntheses of picrotoxinin—one of which was published as recently as June 2020 by the Shenvi lab at Scripp's. This synthesis, like most for this molecule involved the use of carvone as a stereochemical template. The strategy employed the quick formation of the polycyclic core, followed by the manipulation of oxidation states of key carbon atoms in order to produce the target molecule.
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Up until this time, chant theory recognized eight musical modes: the relative natural scales in D, E, F and G, each with their authentic and plagal counterparts, and with the option of B instead of B in several modes.Harold S. Powers, "Mode, §II. Medieval Modal Theory, 3: 11th-Century Syntheses, (i) Italian Theory of Modal Functions, (b) Ambitus." The New Grove Dictionary of Music and Musicians, edited by Stanley Sadie and John Tyrrell (London: Macmillan; New York: Grove's Dictionaries, 2001) (Example 5).
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Enantioselectivity was strongly influenced by the nature of the halide/pseudohalide employed, with aryl triflates coupling partners giving moderate enantiomeric excess (ee) while aryl iodides demonstrated no enantioinduction. This supports hypotheses of both cationic and neutral pathways analogous to the classic Mizoroki–Heck reaction [7, 8]. The asymmetric coupling of azanorbornene scaffolds has also been successful. In particular, the reductive Heck coupling of azanorbornene 19 has allowed for short, enantioselective syntheses of the alkaloid epibatidine and structural analogues [35–38].
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Imagination is the faculty that produces ideas and images in the absence of direct sensory data, often by combining fragments of previous sensory experiences into new syntheses. It is a critical component of mental management as it captures the change involved in improving or optimising the mental processes. The gesture of creative imagination allows for an individual to invent new approaches based on what they already know. This allows individuals to make comparisons and develop responses to problems outside of a logical framework.
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Heating MnO2 in air at below 800 °C produces α-Mn2O3 (higher temperatures produce Mn3O4). γ-Mn2O3 can be produced by oxidation followed by dehydration of manganese(II) hydroxide. Many preparations of nano-crystalline Mn2O3 have been reported, for example syntheses involving oxidation of MnII salts or reduction of MnO2. Manganese(III) oxide is formed by the redox reaction in an alkaline cell: : 2 MnO2 \+ Zn → Mn2O3 \+ ZnO Manganese(III) oxide Mn2O3 must not be confused with MnOOH manganese(III) oxyhydroxide.
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Sedimentary basin analysis is a geologic method by which the history of a sedimentary basin is revealed, by analyzing the sediment fill itself. Aspects of the sediment, namely its composition, primary structures, and internal architecture, can be synthesized into a history of the basin fill. Such a synthesis can reveal how the basin formed, how the sediment fill was transported or precipitated, and reveal sources of the sediment fill. From such syntheses models can be developed to explain broad basin formation mechanisms.
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The reaction conditions and purifications could be easily simplified by just using excess of palladium(II) acetate without benzoquinone, while at a much higher cost. Since the reaction typically employs near- stoichiometric amounts of palladium and is therefore often considered too expensive for industrial usage, some progress has been made in the development of catalytic variants. Despite this shortcoming, the Saegusa oxidation has been used in a number of syntheses as a mild, late-stage method for introduction of functionality in complex molecules.
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They, like farmers, must strategically assess the feasibility and profitability of available strategic and policy options and decide which ones to promote and where, with even greater deals of risks and uncertainties. If reliable estimates could be made of the current and potential patterns of crop productivity, many agricultural development investment and policy decisions would be significantly improved, or made with greater confidence. HarvestChoice and its partners develop databases, tools, analyses, and syntheses designed to improve strategic investment and policy decisions.
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In completing his Ph.D. in the Graduate School of Ohio State University, Calvin Buehler published his dissertation in 1922 titled The Oxidation of Lactose, Glucose, and Galactose by Means of Neutral and Alkaline Potassium Permanganate. His research was conducted under Dr. W. L. Evans and worked alongside C.W. Kreger. Over the span of his career, Buehler would publish over forty-two scholarly articles. Buehler was the co-author of the book Survey of Organic Syntheses, published by Wiley-Interscience publications in 1970.
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Manchester: Hudson Hills Press, 2005. His late work alternated between abstracted, painterly pieces, such as On the Way (1965) or Sun Bleached (1969), and high-key, geometric syntheses of recreational, domestic or urban scenes, often executed in acrylic (e.g., Family Feast, 1971; In, 1972). In these works, he often applied paint in a cool, almost mechanical manner, creating clean-edged, flat areas of interlocking forms that consciousy used negative space and sometimes formed graphic patterns of striping and outlining (e.g.
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This rearrangement reaction is named after its discoverer, Lars Skattebøl, Professor emeritus at the University of Oslo. It proceeds through a carbene reaction intermediate: Skattebøl rearrangement When the cyclopropane ring is fitted with a 2-vinyl group, a cyclopentadiene is formed through a so-called foiled carbene intermediate.Chemistry of gem- dihalocyclopropanes—VI A novel synthesis of cyclopentadienes and fulvenes L. Skattebøl Tetrahedron Volume 23, Issue 3 , 1967, Pages 1107-1117 .Leo A. Paquette and Mark L. McLaughlin Organic Syntheses, CV 8, 223 Link.
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Thermal rearrangements of aromatic hydrocarbons have been shown to be important in areas of chemical research and industry including fullerene synthesis, materials applications, and the formation of soot in combustion. Thermal rearrangements of aceanthrylene and acephenanthrylene can yield fluoranthene, an important species in syntheses of corannulene and fullerenes that proceed through additional internal rearrangements.Richter, H.; Grieco, W. J.; Howard, J. B. Formation Mechanism of Polycyclic Aromatic Hydrocarbons and Fullerenes in Premixed Benzene Flames. Combustion and Flame 1999, 119 (1–2), 1–22.
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Selectivity can be a challenge in nitrations because as a rule more than one compound may result but only one is desired, so alternative products act as contaminants or are simply wasted. Accordingly, it is desirable to design syntheses with suitable selectivity; for example, by controlling the reaction conditions, fluorenone can be selectively trinitrated or tetranitrated. The substituents on aromatic rings affect the rate of this electrophilic aromatic substitution. Deactivating groups such as other nitro groups have an electron-withdrawing effect.
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Some researchers in the field of evolutionary developmental biology proposed another synthesis. They argue that the modern and extended syntheses should mostly center on genes and suggest an integration of embryology with molecular genetics and evolution, aiming to understand how natural selection operates on gene regulation and deep homologies between organisms at the level of highly conserved genes, transcription factors and signalling pathways. By contrast, a different strand of evo-devo following an organismal approach"The Origins of Form". Natural History.
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Preparation of ethyl-diazoacetate: Buchner's first synthesis of cycloheptatriene derivatives in 1885 used photolysis and thermal conditions to generate the carbene. A procedure for preparation of the hazardous starting material needed for carbene generation in the Buchner reaction, ethyl- diazoacetate, is available in Organic Syntheses. In the procedure provided, Searle includes cautionary instructions due to the highly explosive nature of diazoacetic esters. Preparation of the metal carbenoid: Synthesis of the carbene in the 1960s was focused on using copper catalysts for stereoselective propanation.
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The first example of ring-closing metathesis was reported by Dider Villemin in 1980 when he synthesized an Exaltolide precursor using a WCl6/Me4Sn catalyzed metathesis cyclization in 60-65% yield depending on ring size (A). In the following months, Jiro Tsuji reported a similar metathesis reaction describing the preparation of a macrolide catalyzed by WCl6 and dimethyltitanocene (Cp2TiMe2) in a modest 17.9% yield (B).Tsuji, J.; Hashiguchi, S. (1980). “Application of Olefin Metathesis to Organic Synthesis. Syntheses of Civetone and Macrolides”.
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Ring-closing metathesis has been used historically in numerous organic syntheses and continues to be used today in the synthesis of a variety of compounds. The following examples are only representative of the broad utility of RCM, as there are numerous possibilities. For additional examples see the many review articles. Ring-closing metathesis is important in total synthesis. One example is its use in the formation of the 12-membered ring in the synthesis of the naturally occurring cyclophane floresolide.
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At the Futurist Congress, held in Milan on 23 November 1924, the composer also delivered a lecture entitled 'Visible Syntheses, Chromatic Atmospheres and Scenic-Plastic Versions of Music.' Courageously, Casavola risked opposing the escalating cultural autarchy imposed by Benito Mussolini's fascist government after it seized power late in 1922. Bravest of all was his defence of jazz, not merely through his written articles, but also his own compositions; many of Casavola's best pieces employed rhythms and styles closely resembling jazz forms.
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Instead, the byproduct, diazonium-methyl from the other diazomethane molecule, can be attacked by the chloride to produce chloromethane. The unreactive diazoketone can be re-activated and reacted by treatment with hydrogen chloride to give the normal Nierenstein product. The Nierenstein reaction mechanism In some cases, even limiting the amount of diazomethane gives a reaction process that stalls via the neutral diazoketone pathway, requiring the addition of HCl gas to rescue it.McPhee, W. D; Klingsberg, E. Organic Syntheses, Coll. Vol.
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26 (2016): 3543-3546 Novel reaction mechanisms have been used in at least two syntheses, including the original synthesis in 2001. A key step in this synthesis was the reaction of a nitrone and an alkyl halide with zinc in aqueous solution and under sonication. This reaction enabled the stereoselective formation of a C-C bond, ensuring that the product's absolute configuration was correct. Another novel reaction was discovered by a group at the University of California, Irvine in 2007.
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One is called "Chapulines" which consists of images of grasshoppers with a black skull in the middle. And the other is the "Bebidores" which depicts various figures drinking out of vessels most commonly used for pulque. Cholula, despite its importance, has not been studied as intensively as other Mesoamerican sites, and most of what does exist are technical field reports with few syntheses of data gathered. For this reason, it has not played a significant role in the understanding of Mesoamerica to date.
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Only a week later, the Ciba group in Zurich, Leopold Ruzicka (1887–1976) and A. Wettstein, published their synthesis of testosterone. These independent partial syntheses of testosterone from a cholesterol base earned both Butenandt and Ruzicka the joint 1939 Nobel Prize in Chemistry. Testosterone was identified as 17β-hydroxyandrost-4-en-3-one (C19H28O2), a solid polycyclic alcohol with a hydroxyl group at the 17th carbon atom. This also made it obvious that additional modifications on the synthesized testosterone could be made, i.e.
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While the use of solid-supported reagents greatly simplifies the synthesis of compounds, many combinatorial syntheses require multiple steps, each of which still requires some form of purification. Armstrong, et al. describe a one-pot method for generating combinatorial libraries, called multiple-component condensations (MCCs). In this scheme, three or more reagents react such that each reagent is incorporated into the final product in a single step, eliminating the need for a multi-step synthesis that involves many purification steps.
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Cecil Ernest Boord (died 1969) was an American chemist. He graduated in 1907 from Wabash College and joined Ohio State University. He earned the titles of "dean of hydrocarbon chemistry" and "designer and builder of gasolines" through his years of pioneering research in the syntheses and testing of hydrocarbon components of gasoline. In 1955, Dr. Boord was awarded the prized Joseph Sullivant Medal in recognition of "notable achievement" in the arts and sciences by an alumnus or faculty member of Ohio State.
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In 1959 he published the first post-war Futurist manifesto Sassintesi (“Stone Syntheses”). In it he advocated a new form of artistic expression using natural materials - pebbles, stones and rocks formed of various minerals. “The inherent qualities of colour, form, translucence, texture, etc. were to suggest, develop and determine the idea of the artist, while their appearance and positioning produced a harmonious composition that relied much on the stones' natural symbiosis with the cosmos.” His sassintesi were exhibited in Milan in 1961.
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CrCl3 is a Lewis acid, classified as "hard" according to the Hard-Soft Acid-Base theory. It forms a variety of adducts of the type [CrCl3L3]z, where L is a Lewis base. For example, it reacts with pyridine () to form an adduct: :CrCl3 \+ 3 C5H5N → CrCl3(C5H5N)3 Treatment with trimethylsilylchloride in THF gives the anhydrous THF complex:Philip Boudjouk, Jeung-Ho So "Solvated and Unsolvated Anhydrous Metal Chlorides from Metal Chloride Hydrates" Inorganic Syntheses, 2007, vol. 29, p. 108-111. :CrCl3.
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Edward Frankland From an early age, Frankland engaged in original research with great success. Analytical problems, such as the isolation of certain organic radicals, attracted his attention at first, but he soon turned to chemical syntheses. Robert Bunsen is believed to have directed his students, Edward Frankland and Hermann Kolbe, to the investigation of cacodyl, leading to Frankland's discovery of organometallic compounds. After his return to England Frankland achieved the synthesis of diethylzinc and dimethylzinc by the reaction of ethyl iodide and methyl iodide with metallic zinc.
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Chemical synthesis offers two advantages compared with electrochemical synthesis of PTs: a greater selection of monomers, and, using the proper catalysts, the ability to synthesize perfectly regioregular substituted PTs. PTs were chemically synthesized by accident more than a century ago. Chemical syntheses from 2,5-dibromothiophene use Kumada coupling and related reactions Kumada coupling route to PT. Regioregular PTs have been prepared by lithiation 2-bromo-3-alkylthiophenes using Kumada cross-coupling. This method produces approximately 100% HT–HT couplings, according to NMR spectroscopy analysis of the diads.
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The Wolff rearrangement has been used in many total syntheses; the most common use is trapping the ketene intermediate with nucleophiles to form carboxylic acid derivatives. The Arndt-Eistert homologation is a specific example of this use, wherein a carboxylic acid may be elongated by a methylene unit. Another common use is in ring-contraction methods; if the α-diazo ketone is cyclic, the Wolff rearrangement results in a ring-contracted product. The Wolff rearrangement works well in generating ring-strained systems, where other reactions may fail.
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Members of the chemistry department have been awarded three Nobel Prizes and one Wolf Prize for the discovery of novel syntheses and methods. MIT biologists have been awarded six Nobel Prizes for their contributions to genetics, immunology, oncology, and molecular biology. Professor Eric Lander was one of the principal leaders of the Human Genome Project. Positronium atoms, synthetic penicillin, synthetic self-replicating molecules, and the genetic bases for Amyotrophic lateral sclerosis (also known as ALS or Lou Gehrig's disease) and Huntington's disease were first discovered at MIT.
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In the laboratory, K2FeO4 is prepared by oxidizing an alkaline solution of an iron(III) salt with concentrated chlorine bleach.Schreyer, J. M.; Thompson, G. W.; Ockerman, L. T. "Potassium Ferrate(VI)" Inorganic Syntheses, 1953 volume IV, pages 164-168. The salt is isostructural with K2MnO4, K2SO4, and K2CrO4. The solid consists of K+ and the tetrahedral FeO42− anion, with Fe-O distances of 1.66 Å.Hoppe, M. L.; Schlemper, E. O.; Murmann, R. K. "Structure of Dipotassium Ferrate(VI)" Acta Crystallographica 1982, volume B38, pp. 2237-2239. .
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The final step involves reacting this product with BH3 in THF, then reacting the product with piperazine in MeOH at reflux. 6-chloro-2-fluoro-3-pyridineacetamide is used as an intermediate in most syntheses, which is then reacted through these three general steps to produce phantasmidine. The structure of this intermediate is shown as the starting reagent in the general reaction mechanism above. Modern synthetic procedures, however, generally begin with 2-chloro-6-fluoropyridine as the starting reagent, due to its commercial availability.
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Well-crystallized graphitic carbon nitride nanocrystallites also can be have prepared via benzene-thermal reaction between C3N3Cl3 and NaNH2 at 180–220 °C for 8–12 h. Recently, a new method of syntheses of graphitic carbon nitrides by heating at 400-600 °C of a mixture of melamine and uric acid in the presence of alumina has been reported. Alumina favored the deposition of the graphitic carbon nitrides layers on the exposed surface. This method can be assimilated to an in situ chemical vapor deposition (CVD).
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This neuroprotective pathway involves control of neuronal activity by perisynaptic astrocytes and neuronal glutamate release, with the establishment of tripartite synapses. The Nrf2/ARE activation leads to a higher expression of enzymes involved in glutathione syntheses and metabolism, that have a key role in antioxidant response. The LKB1/NUAK1 signalling pathway regulates terminal axon branching at cortical neurons, via local immobilized mitochondria capture. Besides NUAK1, LKB1 kinase acts under other effectors enzymes as SAD-A/B and MARK, therefore regulating neuronal polarization and axonal growth, respectively.
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The laboratory syntheses of dolomite by Von Morlot involved finely powdered, pure calcite crystals mixed with a quantity of magnesium sulphate heptahydrate. The mixture was enclosed in a rather thick glass tube, which was closed by melting its open end. The glass tube was heated in an oil bath to a temperature of 200° Reamur (= 250° Celsius). The high pressure developing inside the glass tube was prevented from blowing it up through fitting it in a (steel) gun barrel filled up with fine sand.
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Faul joined the process chemistry group at Eli Lilly in 1993, and joined Amgen's process group in 2003, rising eventually to its Executive Director. According to a biosketch at Organic Syntheses, Faul has expertise in Good Manufacturing Process scale-up of both chemical and biological therapeutics, and coordinates groups of external partners through licensing, regulatory, and program development issues. She attributes much of Amgen's success in this area to early adoption of new technologies, such as supercritical carbon dioxide purification and ultra-high performance liquid chromatography (uPLC).
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The vast majority of improvements to this reaction have focused on rendering the transformation catalytic with respect to the palladium salt, primarily due to its high cost. The original conditions, though technically catalytic, still require 50 mol% of palladium(II) acetate, raising the cost to prohibitively high levels for large scale syntheses. The major advances in catalytic versions of this reaction have steered towards co- oxidants that regenerate the palladium(II) species effectively. Specifically, conditions using atmospheric oxygen as well as stoichiometric allylcarbonate have been developed.
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Pempidine is an aliphatic, sterically hindered, cyclic, tertiary amine, which is a weak base: in its protonated form it has a pKa of 11.25. Pempidine is a liquid with a boiling point of 187–188 °C and a density of 0.858 g/cm3. Two early syntheses of this compound are those of Leonard and Hauck, and Hall. These are very similar in principle: Leonard and Hauck reacted phorone with ammonia, to produce 2,2,6,6-tetramethyl-4-piperidone,The "trivial" name of this compound is triacetonamine.
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Warren is well known for his university-level textbooks Chemistry of the Carbonyl Group (1974), Designing Organic Syntheses: The Synthon Approach (1978), Organic Synthesis: The Disconnection Approach (first edition 1982, second edition 2008), and its graduate-level sequel, Organic Synthesis: Strategy and Control (2007). He is perhaps best known as one of the authors of the best-selling undergraduate text Organic Chemistry (first edition 2000, second edition 2012), which he wrote with his former students Jonathan Clayden and Nick Greeves, and fellow Cambridge lecturer Peter Wothers.
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As is often the case with parent heterocyclic ring systems, the synthesis of pyrimidine is not that common and is usually performed by removing functional groups from derivatives. Primary syntheses in quantity involving formamide have been reported. As a class, pyrimidines are typically synthesized by the principal synthesis involving cyclization of β-dicarbonyl compounds with N–C–N compounds. Reaction of the former with amidines to give 2-substituted pyrimidines, with urea to give 2-pyrimidinones, and guanidines to give 2-aminopyrimidines are typical.
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Thiophosphoryl chloride can be generated by several reactions starting from phosphorus trichloride. The most common and practical synthesis, hence used in industrial manufacturing, is directly reacting phosphorus trichloride with excess sulfur at 180 °C.. :PCl3 \+ S → PSCl3 Using this method, yields can be very high after purification by distillation. Catalysts facilitate the reaction at lower temperatures, but are not usually necessary. Alternatively, it is obtained by combining phosphorus pentasulfide and phosphorus pentachloride.Martin, D. R.; Duvall, W. M. “Phosphorus(V) Sulfochloride” Inorganic Syntheses, 1953, Volume IV, p73. .
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Note that anion formation has been omitted. An alternative to the standard Favorskii rearrangement, is to perform what can be thought of as a negative pinacol rearrangement where an anionic group encourages a bond aligned with a leaving group to migrate and expel the leaving group, which has been used in several syntheses. It should also be noted that the so-called "quasi-Favorskii rearrangement" proceeds without an additional nucleophile to form the final contracted product. A general pinacol type rearrangement to an unequal 5,7 ring system.
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In April 1955, Mouravieff became a privat-docent at University of Geneva where he taught two courses until 1961, one concerning the history of Russia before 1917 and the other on esoteric philosophy. This last course was entitled: "An Introduction to esoteric philosophy according to the esoteric tradition of Eastern Orthodoxy". This course regularly brought together between ten and thirty students. The introductory speech of the 1956 academic year on the theme of "The Problem of the New Man" was published by the journal "Syntheses".
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3-Bromofuran is a versatile chemical intermediate, in that it is a convenient starting material for 3-substituted furans, and as such, has found application in the syntheses of drug substances or candidate drugs in a number of therapeutic classes, including chemotherapy agents, HIV drugs, type 2 diabetes, osteoporosisZhi-Cai Shi, et al., " Preparation of 4-[6-(2,2,2-trifluoro-1-phenylethoxy)pyrimidin-4-yl]-(S)-phenylalanine derivative tryptophan hydroxylase inhibitors for treating osteoporosis ", US PCT Int. Appl. (2010), WO 2010065333 A1 20100610. and Alzheimer's disease.
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Star-shaped polymers were first reported by John Schaefgen and Paul Flory in 1948 while studying multichain polymers; they synthesized star-shaped polyamides. The next major publication regarding star- shaped polymers was in 1962 by Maurice Morton et al. Their research presented the first study demonstrating a method to create well-defined star-shaped polymers; this route was through living anionic polymerization. Many studies on the characteristics, syntheses, and applications of star-shaped polymers have since been undertaken and remain an active area of study.
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The Eschenmoser sulfide contraction is an organic reaction first described by Albert Eschenmoser for the synthesis of 1,3-dicarbonyl compounds from a thioester.Organic syntheses based on name reactions, Volume 22 2002 Alfred Hassner,C. StumerA New Type of Corrin Synthesis Angewandte Chemie International Edition in English Volume 8, Issue 5, Date: May 1969, Pages: 343-348 Yasuji Yamada, D. Miljkovic, P. Wehrli, B. Golding, P. Löliger, R. Keese, K. Müller, A. Eschenmoser Sulfidkontraktion via alkylative Kupplung: Eine methode zur darstellung von -dicarbonylderivaten. Über synthetische methoden, 1.
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As relates to causality, Smuts makes reference to A. N. Whitehead, and indirectly Baruch Spinoza; the Whitehead premise is that organic mechanism is a fundamental process which realizes and actualizes individual syntheses or unities. Holism (the factor) exemplifies this same idea while emphasizing the holistic character of the process. The whole completely transforms the concept of causality: results are not directly a function of causes. The whole absorbs and integrates the cause into its own activity: results appear as the consequence of the activity of the whole.
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Food sources high in coumestans include split peas, pinto beans, lima beans, and especially alfalfa and clover sprouts. Coumestrol has about the same binding affinity for the ER-β estrogen receptor as 17β-estradiol, but much less affinity than 17α-estradiol, although the estrogenic potency of coumestrol at both receptors is much less than that of 17β-estradiol. Because of the estrogenic activity of some coumestans, a variety of syntheses have been developed that allow the preparation of coumestans so that their pharmacological effects can be explored.
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Robinson annulation reaction Formation of cyclohexenone and derivatives are important in chemistry for their application to the synthesis of many natural products and other interesting organic compounds such as antibiotics and steroids. Specifically, the synthesis of cortisone is completed through the use of the Robinson annulation. The initial paper on the Robinson annulation was published by William Rapson and Robert Robinson while Rapson studied at Oxford with professor Robinson. Before their work, cyclohexenone syntheses were not derived from the α,β-unsaturated ketone component.
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Both peroxyphosphoric acids were first synthesized and characterized in 1910 by Julius Schmidlin and Paul Massini via the reaction between phosphorus pentoxide and highly-concentrated aqueous solution of hydrogen peroxide. However, this reaction proceeds very vigorously and is difficult to control. Aside from phosphorus pentoxide, syntheses from metaphosphoric acid and diphosphoric acid were also reported. : P2O5 + 2H2O2 + H2O -> 2H3PO5 : H4P4O12 + 4H2O2 -> 4H3PO5 : H4P2O7 + H2O2 -> H3PO5 + H3PO4 A less vigorous method of preparing peroxyphosphoric acid by introducing the inert solvent acetonitrile was described by Gerrit Toennies in 1937.
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She also worked on developing syntheses of drugs that had previously been imported from Germany including beta-Eucaine, Phenacetin and Procaine. In 1920, Whiteley received the honor of the Order of British Empire for her scientific contributions to war efforts. An earlier biography by Mary R.S. Creese of the University of Kansas was published in 1997 in the American Chemical Society's Bulletin for the History of Chemistry, and references what appears to be an obituary published 40 years previously in the year after Whiteley's death.
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He became known for syntheses on Norwegian history, and emphasised the roles of peasants and wage labourers as historical agents who found their place in an expanding notion of the Norwegian nation. He was also interested in the United States and its history, and was a pioneer in Norway in this respect. Koht's views on the Norwegian language also gave him nationwide academic recognition. He championed the Samnorsk language reform, the declared aim of which was to consolidate the two standards of written Norwegian.
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The Nobel Prize-winning multi-step syntheses of Hemin and Chlorophyll by Hans Fischer. inspired the work of his student Paul Rothemund to develop a simple one pot synthesis of porphyrins. In 1935 Paul Rothemund reported the formation of porphyrin, from a simple reaction of pyrrole with gaseous acetaldehyde or formaldehyde in methanol followed by treatment with various concentrations of hydrochloric acid. One year later Paul Rothemund announced the applicability of his reaction to other aldehydes, by which he was able to explore large number of porphyrins.
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Cynaropicrin is synthesized in the leaves of the artichoke plant and was found to accumulate in the trichomes. While the full mechanism of biosynthesis of cynaropicrin is unknown, it is proposed that biosynthesis starts with three isoprene C5-units, which are processed by the mevalonate pathway to form farnesyl pyrophosphate (FPP). With germacrene A and germacrene A acid as intermediates, FPP is converted into costunolide using two syntheses and a cytochrome P450 oxidase. Multiple yet unknown reactions occur to first form guaianolide and later cynaropicrin.
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Reaction enthalpy changes can be determined by calorimetry for many reactions. The values are usually stated for processes with the same initial and final temperatures and pressures, although the conditions can vary during the reaction. Hess' law can be used to determine the overall energy required for a chemical reaction, when it can be divided into synthetic steps that are individually easier to characterize. This affords the compilation of standard enthalpies of formation, that may be used as a basis to design complex syntheses.
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Gallo-Roman temple dedicated to Lenus, rebuilt in Pommern, Rhineland-Palatinate. Ancient Germanic paganism was a polytheistic religion practised in prehistoric Germany and Scandinavia, as well as Roman territories of Germania by the 1st century AD. It had a pantheon of deities that included Donar/Thunar, Wuotan/Wodan, Frouwa/Frua, Balder/Phol/Baldag, and others shared with northern Germanic paganism. Celtic paganism and later Gallo-Roman syntheses were instead practised in western and southern parts of modern Germany, while Slavic paganism was practised in the east.
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Dicarbaboranes can be prepared from boron hydrides using alkynes as the source of the two carbon centers. In addition to the closo-C2BnHn+2 series mentioned above, several open-cage dicarbon species are known including nido-C2B3H7 (isostructural and isoelectronic with B5H9) and arachno-C2B7H13. Structure of nido-C2B4H8, highlighting some trends: carbon at the low connectivity sites, bridging hydrogen between B centers on open face. Syntheses of icosahedral closo-dicarbadodecaborane derivatives (R2C2B10H10) employ alkynes as the R2C2 source and decaborane (B10H14) to supply the B10 unit.
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The Curtius rearrangement is tolerant of a large variety of functional groups, and has significant synthetic utility, as many different groups can be incorporated depending on the choice of nucleophile used to attack the isocyanate. For example, when carried out in the presence of tert-butanol, the reaction generates Boc-protected amines, useful intermediates in organic synthesis. Likewise, when the Curtius reaction is performed in the presence of benzyl alcohol, Cbz-protected amines are formed. The Curtius rearrangement is used in the syntheses of the drugs tranylcypromine, candesartan, bromadol, terguride, benzydamine, gabapentin, igmesine and tecadenoson.
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Among Professor Orchard's key contributions was the development of a systematic process for the computer-aided design of filters. During the early years of computer-aided filter design, when the synthesis of a single circuit required several days of multiple-precision computation, his method had an important beneficial effect. He was instrumental in introducing into switched capacitor filter design the bilinear s-z mapping, previously used solely in digital filter design, and in developing a methodology that allowed the use of arbitrary active-RC models for switched-capacitor filter syntheses.
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Intermolecular and intramolecular ketene [2+2] cycloadditions Ketene [2 + 2] cycloaddition reactions have been used in many total syntheses since Corey's use of the [2 + 2] cyclization in synthesizing the prostaglandins. Robert Ireland's synthesis of (±)-aphidicolin uses the Wolff rearrangement to do a tandem ring-contraction, and [2 + 2] cycloaddition. Synthesis of (±)-aphidicolin The Danheiser benzannulation photolyses α-diazo ketones and traps with an alkyne, which undergoes a pericyclic cascade, to ultimately form versatilely substituted phenols. The first step in the benzannulation is the photolysis of an α-diazo ketone to form a vinylketene.
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A.S. Peshkovsky, S.L. Peshkovsky "Industrial-scale processing of liquids by high-intensity acoustic cavitation - the underlying theory and ultrasonic equipment design principles", In: Nowak F.M, ed., Sonochemistry: Theory, Reactions and Syntheses, and Applications, Hauppauge, NY: Nova Science Publishers; 2010.A.S. Peshkovsky, S.L. Peshkovsky "Acoustic Cavitation Theory and Equipment Design Principles for Industrial Applications of High-Intensity Ultrasound", Book Series: Physics Research and Technology, Hauppauge, NY: Nova Science Publishers; 2010. Finding the optimum operation condition for this equipment is a challenge for process engineers and needs deep knowledge about side effects of ultrasonic processors.
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The encounter of Goethe with Hafiz's ghazals became so inspiring to Goethe, that he produced his own and "led the way to the discovery of Persian poetry by the Romantics", according to Shusha Guppy. His west-ostlicher, and collection of poetry in general, gradually came to function as "an influential model for religious and literary syntheses between the ‘occident’ and the ‘orient’ in the 19th century", according to Jeffrey Einboden of Magdalene College in Cambridge, England, who is currently a professor at Northern Illinois University in DeKalb, IL.
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The first section of the film is coupled with an apparently synchronous on-location soundtrack that includes realistic syntheses of bird- sounds, a distant jeep, waves lapping on the beach and human voices. It is not initially evident that these sounds are not authentically tied to the images they accompany. Conner first allows doubt of his simulation when he breaks the sound delay displacement to set the sound of the blast "in sync" with the visual event. In the first shots of the film, the blast is heard moments after it is seen.
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Church of Saint Nicholas Yamnytsia (, ) is a village of Tysmenytsia Raion, Ukraine, just few miles north from Ivano-Frankivsk. The village is better known for the Battle of Yamnytsia during the Kerensky Offensive, when the Russian Imperial Army successfully secured area north of Stanislau for a brief period of time (June 27–July 6, 1917). During the battle, all the Kornilov Strike regiment soldiers were awarded the Cross of St. George. Today the village is better known for the chemical factory Barva that was built in 1975 as a factory of fine organic syntheses.
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As the period of the thaw was encouraging translations in the field of arts as well, the Meridiane Press started to publish an important collection of books and also anthologies with texts on currents in art as well as syntheses. On the occasion of their first trips abroad, the artist and his wife would always bring new art books and magazines. Thus his wife returned from her tourist visit to England with subscriptions to Burlington Art Magazine and Studio International, one of its issues containing a review of Athena Tacha's Brancusi's Birds.
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An example of a material prepared using a tube furnace is the superconductor YBa2Cu3O7. A mixture of finely powdered CuO, BaO, and Y2O3, in the appropriate molar ratio, contained in a platinum or alumina "boat," is heated in a tube furnace at several hundred degrees under flowing oxygen. Similarly tantalum disulfide is prepared in a tube furnace followed by purification, also in a tube furnace using the technique of chemical vapor transport.J. F. Revelli, "Tantalum Disulfide (TaS2) and Its Intercalation Compounds" Inorganic Syntheses 1995, volume 30, pp. 155.
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The Pacific Institute of Public Policy (PiPP) is an independent, non-profit, regionally focused think tank based in Port Vila, Vanuatu. The stated aim of PiPP is to stimulate and support informed policy debate in the Pacific. A central feature of PiPP’s model of engagement with policy stakeholders is the distribution of research via several media including: research syntheses, discussion papers, forums, public debates, social networking, audio and video podcasts, press, radio and television. PiPP was established on November 21, 2007 under the Vanuatu Charitable Associations (Incorporation) Act [CAP.140].
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His popularity began when he published his 1968 work La révolte contre le père (The revolt against the father). Deleuze and Guattari assessed this book as one example of the "drivel on Oedipus".Deleuze, Guattari (1972) Anti-Œdipus, section 2.6 A recapitulation of the three syntheses p.116, 118-9 Mendel argued that the father "died over a period of thousands of years" and that the "internalization" corresponding to the paternal image was produced during the Paleolithic right up until the start of the Neolithic, "approximately 8,000 years ago".
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Although syntheses using the isolated Tebbe reagent give a cleaner product, successful procedures using the reagent "in situ" have been reported. Instead of isolating the Tebbe reagent, the solution is merely cooled in an ice bath or dry ice bath before adding the starting material. An alternative but less convenient synthesis entails the use of dimethyltitanocene (Petasis reagent): ::Cp2Ti(CH3)2 \+ Al(CH3)2Cl -> Cp2TiCH2AlCl(CH3)2 \+ CH4 One drawback to this method, aside from requiring Cp2Ti(CH3)2, is the difficulty of separating product from unreacted starting reagent.
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Triphenylphosphite forms zero-valent complexes of the type M[P(OC6H5)3]4 for M = Ni, Pd, Pt. The colourless nickel complex (melting point 147 °C) can be prepared from the nickel(0) complex of cycloocta-1,5-diene:Ittel, S. D. "Olefin, Acetylene, Phosphine, Isocyanide, and Diazene Complexes of Nickel(0)" Inorganic Syntheses, 1977, volume XVII, p. 117–124. : Ni(COD)2 \+ 4 P(OC6H5)3 → Ni[P(OC6H5)3]4 \+ 2 COD It also forms a variety of Fe(0) and Fe(II) complexes such as the dihydride H2Fe[P(OC6H5)3]4.
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Niobium pentachloride liquid and vapor Industrially, niobium pentachloride is obtained by direct chlorination of niobium metal at 300 to 350 °C: :2 Nb + 5 Cl2 → 2 NbCl5 In the laboratory, niobium pentachloride is often prepared from Nb2O5, the main problem being incomplete reaction to give the oxyhalides. The conversion can be effected with thionyl chloride:D. Brown "Niobium(V) Chloride and Hexachloroniobates(V)" Inorganic Syntheses, 1957 Volume 9, pp. 88–92. It also can be prepared by chlorination of niobium pentoxide in the presence of carbon at 300 °C.
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In numerous industries such as agrochemicals and pharmaceuticals, halogenated chemicals abound. Aryl halides are also important intermediates in the syntheses of other compounds due to their versatility in reactions such as nucleophilic aromatic substitution and coupling reactions. Traditionally, in chemical synthesis, arenes are halogenated by electrophilic aromatic substitution, a process that often suffers from poor regioselectivity and makes use of toxic reagents and catalysts under harsh reaction conditions. Tryptophan 7-halogenase circumvents these issues, halogenating its substrate regioselectively and using halide salts and molecular oxygen as reagents at room temperature and fairly neutral pH.
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He searched for ways of obtaining cyclobutadiene, while explaining the chemistry of this unstable substance and isolating its dimers. His research interests were also in the oxidation of open-chain and aromatic hydrocarbons with chromic acid and chromic oxychloride. He found new methods for the synthesis of pyrylium salts (Balaban–Nenitzescu–Praill synthesis), of carbenes, tryptamine, serotonin, two new syntheses for the indole nucleus, and a new method of polymerisation of ethylene.Mateescu placing capstone on 30-year career by Susan Griffith His research was substantiated in more than 200 papers.
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A general scheme for the divergent synthesis of PAMAM dendrimers, with ethylene diamine as a core initiator. The scheme is color-coded by generation number, with the red ethylene diamine core serving as initiator core, orange as Generation 0 and orange/green as Generations 1, respectively. The scheme shown is currently the most widely adopted approach in commercial syntheses of PAMAM. Divergent synthesis refers to the sequential "growth" of a dendrimer layer by layer, starting with a core "initiator" molecule which contains functional groups capable of acting as active sites in the initial reaction.
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Avison's work prompted other such British aesthetic syntheses, from James Beattie, Thomas Twining and Daniel Webb; and the theme was picked up by German writers. Brown's work has been identified as belonging to conjectural history; he described in a 1761 letter to Garrick his stadial method of "deducing things from their state in savage life, through the several stages of civilized society."Ilias Chrissochoidis, Reforming Handel: John Brown and "The Cure of Saul" (1763), Journal of the Royal Musical Association Vol. 136, No. 2 (2011), pp. 207–245, at p. 212.
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During his time in Japan, the three men were exposed to the nationalist debates "then ranging in the Japanese art world over the modernizing impact of Western art on Japan's local artistic traditions." Jianfu became interested in the syntheses of Western and traditional approaches, which were parallel to work in the contemporary Japanese art world. Jianfu, along with his peers of the Lingnan School, saw this blend of styles as a model for modern national art. Many of the Lingnan students joined Sun Yat-sen's anti-Manchu movement, a revolutionary nationalist movement.
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The wide applicability of the Saegusa–Ito oxidation is exemplified by its use in several classic syntheses of complex molecules. The synthesis of morphine by Tohru Fukuyama in 2006 is one such example, in which the transformation tolerates the presence of carbamate and ether substituents. Fukuyama Synthesis of Morphine Samuel J. Danishefsky's synthesis of both (+) and (-) peribysin began with a Saegusa–Ito oxidation of the Diels-Alder adduct of carvone and 3-trimethylsilyloxy-1,3-butadiene to yield the enone below. In this case the oxidation tolerated the presence of alkene and carbonyl moieties.
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In 2017, he became a distinguished professor and the associate director of the IBS Center for Genomic Integrity in UNIST, headed by Myung Kyungjae. Located in Ulsan City, Republic of Korea, the new laboratory is divided into three sections; DNA Damage Repair, Molecular Cancer Research, and Cancer Therapeutics Mechanisms. The Schärer Laboratory is best known for the development of syntheses of DNA interstrand crosslinks and other DNA lesions and mechanistic studies of human nucleotide excision repair and interstrand crosslink repair and structure-specific nucleases, such as ERCC1-XPF and XPG.
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Being a relatively electropositive metal, indium reacts quickly with chlorine to give the trichloride. Indium trichloride is very soluble and deliquescent.Indium Trichloride A synthesis has been reported using an electrochemical cell in a mixed methanol-benzene solution.Habeeb, J. J.; Tuck, D. G. "Electrochemical Synthesis of Indium(III) Complexes" Inorganic Syntheses, 1979, volume XIX, Like AlCl3 and TlCl3, InCl3 crystallizes as a layered structure consisting of a close-packed chloride arrangement containing layers of octahedrally coordinated In(III) centers,Egon Wiberg, Arnold Frederick Holleman (2001) Inorganic Chemistry, Elsevier a structure akin to that seen in YCl3.
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Thus obtained materials were reported to be poorly soluble and unstable toward photooxidation. An obvious drawback of reported syntheses of TAPs is a need for harsh conditions of condensation or aromatization steps, which are poorly compatible with the emerging huge and fragile TAP system. This results in low yields and poor quality of the obtained materials and limits opportunities of introducing functionality to improve solubility and stability or to modulate optical properties. As an advanced method delivering tetraanthraporphyrins, the dihydroisoindole method based on an oxidative aromatization of the closest partially hydrogenated porphyrin precursor was applied.
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Alkyl nitriles are sufficiently acidic to form nitrile anions, which alkylate a wide variety of electrophiles. Key to the exceptional nucleophilicity is the small steric demand of the CN unit combined with its inductive stabilization. These features make nitriles ideal for creating new carbon-carbon bonds in sterically demanding environments for use in syntheses of medicinal chemistry. Recent developments have shown that the nature of the metal counter-ion causes different coordination to either the nitrile nitrogen or the adjacent nucleophilic carbon, often with profound differences in reactivity and stereochemistry.
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Little is known of the opinions of these physicians, or their tenets. In modern Tibetan Buddhism, the Eclectic school (Ris-med) referred to a movement that seeks to combine the religious and philosophical systems of different lineages in order to develop the best teachings of the whole tradition. It has a syncretic character, open to syntheses with classical greek and Western thought.Robin Kornman, 'The Influence of the Epic of King Gesar of Ling on Chögyam Trungpa,' in Fabrice Midal (ed.) Recalling Chögyam Trungpa, Shambhala Publications, 2005, p.347.
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In contrast to the canonical signaling that relies on NEMO-IKK2 mediated degradation of IκBα, -β, -ε, non-canonical signaling depends on NIK mediated processing of p100 into p52. Given their distinct regulations, these two pathways were thought to be independent of each other. However, it was found that syntheses of the constituents of the non-canonical pathway, viz RelB and p52, are controlled by canonical IKK2-IκB-RelA:p50 signaling. Moreover, generation of the canonical and non-canonical dimers, viz RelA:p50 and RelB:p52, within the cellular milieu are mechanistically interlinked.
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This compound was then subjected to further iodination and sequential Sonogashira couplings to generate a receptor for anions such as Cl− and Br−. Taylor Tellurophene However, metal-catalyzed cross-coupling reactions to synthesize 3-functionalized tellurophenes were deemed to be cumbersome as they required 3-bromo- or 3-iodo-tellurophenes, the syntheses of which could be quite complicated. An alternative method was reported by Seferos et al. in 2013, but this method was hindered by low yields and the use of expensive starting materials such as the Weinreb amide. In 2018, Han et al.
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Chlorobis(cyclooctene)rhodium dimer is an organorhodium compound with the formula Rh2Cl2(C8H14)4, where C8H14 is cis-cyclooctene. Sometimes abbreviated Rh2Cl2(coe)4, it is a red-brown, air-sensitive solid that is a precursor to many other organorhodium compounds and catalysts. The complex is prepared by treating an alcohol solution of hydrated rhodium trichloride with cyclooctene at room temperature.Van der Ent, A.; Onderdelinden, A. L. "Chlorobis(cyclooctene)rhodium(I) and di-μ-chlorobis[bis(cryclooctene)iridium] (I) complexes" Inorganic Syntheses 1973, volume 14, pp. 92-5.
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The complex is prepared by treating an aqueous methanolic solution of hydrated rhodium trichloride with ethylene at room temperature. Rh(III) is reduced with oxidation of ethylene to acetaldehyde: :2 RhCl3(H2O)3 \+ 6 C2H4 → Rh2Cl2(C2H4)4 \+ 2 CH3CHO + 4 HCl + 4 H2O Reflecting the lability of its ligands, the complex does not tolerate recrystallization.Richard Cramer "Di-μ-chlorotetrakis(ethylene)dirhodium(I), 2,4-pentanedionatobis(ethylene)rhodium(I), and di-μ- chlorotetracarbonyldirhodium(I)" Inorganic Syntheses 1974, vol. 15, pp. 14-18.. The complex reacts slowly with water to give acetaldehyde.
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Iridium and ruthenium complexes are used in these metal-catalyzed transfer hydrogenative asymmetric alcohol C-C couplings. Krische and coworkers have developed cyclometalated π-allyliridium(III) ortho-C,O-benzoate complexes derived from [Ir(cod)Cl]2, allyl acetate, various 4-substituted-3-nitro- benzoic acids, and axially chiral bis(phosphine) ligands for these transformations. These catalyst complexes are often generated in situ, but they can also be pre-generated and isolated as they are robust and air-stable. Shown below are syntheses of two catalysts used for these transformations.
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Decomposition of Pt2(dba)3 under hydrogen gas in toluene yielded the formation of nanowires with 2–3 nm diameter independent of HDA concentration. The length of these nanowires was found to be inversely proportional to the concentration of HDA present in solution. When these nanowire syntheses were repeated using reduced concentrations of Pt2(dba)3, there was little effect on the size, length or distribution of the nanowires formed. Platinum nanoparticles of controlled shape and size have also been accessed through varying the ratio of polymer capping agent concentration to precursor concentration.
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Historically, it is generally accepted that the first free radical was identified by Moses Gomberg in 1900; this radical was triphenylmethyl radical. While in general the use of free radicals in organic transformations is difficult to control, organic syntheses with free radicals began in 1937 with Heyes and Waters. After 1940, deeper insights into the formation, structure and reactions of free radicals showed how to control these reactive species in chemical reactions. However, in the 1970s, Lamb and Julia witnessed the beginning of new synthetic methodologies involving free radicals.
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Interpretive discussions are an effective pedagogical method throughout educational systems in classes of nearly every subject and grade. A major goal of pedagogical interpretive discussions is for students to delve deeply into texts in order to better understand their meanings. Pedagogical interpretive discussions typically culminate with syntheses of arguments presented, engaging students in critical thinking as they infer meaning from texts, formulate personal opinions, respectfully argue for their own interpretations and synthesize arguments. Over the course of discussions, participants benefit from cognitive exercise as well as communication and social relationship skill-building.
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In the mid nineteenth century, the coal tar industry, particularly in England, produced the precursors needed for a large amount of organic syntheses, in large quantities. For the first eight years after the first marketable synthetic dye, Mauveine, until the middle of the 1860s, British and French firms were the major dye producers. The second half of the 1860s saw German dye works surpassing their competition in both capacity and market share. During 1870, German firms were responsible for roughly half of the world's production of dyes and pigments.
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Archaeological evidence clearly indicates that starting in the first century BC, iron and cereal agriculture (millet and sorghum) spread together southward from southern Tanzania and northern Zambia, all the way to the eastern Cape region of present South Africa by the third of fourth century AD.Killick, D. (2014) Cairo to Cape: the spread of metallurgy through eastern and southern Africa. In Archaeometallurgy in Global Perspective: Methods and Syntheses, edited by Ben Roberts and Christopher Thornton, pp. 507-528. New York: Springer. It seems highly probable that this occurred through migrations of Bantu-speaking peoples.
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The result of first-strand syntheses, RNA-DNA hybrids, can be processed through multiple second-strand synthesis methods or processed directly in downstream assays. An early method known as hairpin-primed synthesis relied on hairpin formation on the 3' end of the first-strand cDNA to prime second-strand synthesis. However, priming is random and hairpin hydrolysis leads to loss of information. The Gubler and Hoffman Procedure uses E. Coli RNase H to nick mRNA that is replaced with E. Coli DNA Polymerase I and sealed with E. Coli DNA Ligase.
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Sauvage was born in Paris in 1944, and earned his PhD degree from the Université Louis-Pasteur under the supervision of Jean-Marie Lehn, himself a 1987 laureate of the Nobel Prize in Chemistry. During his doctoral work, he contributed to the first syntheses of the cryptand ligands. After postdoctoral research with Malcolm L. H. Green, he returned to Strasbourg, where he is now emeritus professor. Sauvage's scientific work has focused on creating molecules that mimic the functions of machines by changing their conformation in response to an external signal.
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There are also significant environmental benefits over conventional organic solvents. Industrial syntheses that are performed at supercritical conditions include those of polyethylene from supercritical ethene, isopropyl alcohol from supercritical propene, 2-butanol from supercritical butene, and ammonia from a supercritical mix of nitrogen and hydrogen. Other reactions were, in the past, performed industrially in supercritical conditions, including the synthesis of methanol and thermal (non-catalytic) oil cracking. Because of the development of effective catalysts, the required temperatures of those two processes have been reduced and are no longer supercritical.
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These syntheses use as a starting material, obtained from and concentrated hydrochloric acid and ammonium chloride. Hapticity is a term to describe the coordination of a group of contiguous atoms of a ligand bound to the central atom; it is indicated by the Greek character eta, η. Yttrium complexes were the first examples of complexes where carboranyl ligands were bound to a d0-metal center through a η7-hapticity. Vaporization of the graphite intercalation compounds graphite–Y or graphite– leads to the formation of endohedral fullerenes such as Y@C82.
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The first morphine total synthesis, devised by Marshall D. Gates, Jr. in 1952, remains a widely used example of total synthesis. Several other syntheses were reported, notably by the research groups of Rice, Evans, Fuchs, Parker, Overman, Mulzer-Trauner, White, Taber, Trost, Fukuyama, Guillou, and Stork. Because of the stereochemical complexity and consequent synthetic challenge presented by this polycyclic structure, Michael Freemantle has expressed the view that it is "highly unlikely" that a chemical synthesis will ever be cost-effective such that it could compete with the cost of producing morphine from the opium poppy.
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Hydrofluoric acid is both corrosive and toxic, making it unappealing to work with; as such a number of alternative processes have been developed for small-scale syntheses. Potassium heptafluorotantalate can be produced by both anhydrous and wet methods. The anhydrous method involves the reaction of tantalum oxide with potassium bifluoride or ammonium bifluoride according to the following equation:Agulyansky, A. "Potassium fluorotantalate in solid, dissolved and molten conditions" J. Fluorine Chemistry 2003, 155-161. :Ta2O5 \+ 4 KHF2 \+ 6 HF → 2 K2[TaF7] + 5 H2O The method was originally reported by Berzelius.
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In the 1960s, Michel Foucault renewed the argument that moral treatment had really been a new form of moral oppression, replacing physical oppression, and his arguments were widely adopted within the antipsychiatry movement. Foucault was interested in ideas of "the other" and how society defines normalcy by defining the abnormal and its relationship to the normal. A patient in the asylum had to go through four moral syntheses: silence, recognition in the mirror, perpetual judgment, and the apotheosis of the medical personage. The mad were ignored and verbally isolated.
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The structure of nicotinamide consists of a pyridine ring to which a primary amide group is attached in the meta position. It is an amide of nicotinic acid. As an aromatic compound, it undergoes electrophilic substitution reactions and transformations of its two functional groups. Examples of these reactions reported in Organic Syntheses include the preparation of 2-chloronicotinonitrile by a two-step process via the N-oxide, :500px from nicotinonitrile by reaction with phosphorus pentoxide, and from 3-aminopyridine by reaction with a solution of sodium hypobromite, prepared in situ from bromine and sodium hydroxide.
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This occurs as a result of magnesium complexation by carboxyl groups associated with organic matter. Vast deposits of dolomite are present in the geological record, but the mineral is relatively rare in modern environments. Reproducible, inorganic low-temperature syntheses of dolomite and magnesite were published for the first time in 1999. Those laboratory experiments showed how the initial precipitation of a metastable "precursor" (such as magnesium calcite) will change gradually into more and more of the stable phase (such as dolomite or magnesite) during periodical intervals of dissolution and re-precipitation.
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The compound is prepared by thermal reaction of the triene with molybdenum hexacarbonyl:F. A. Cotton, J. A. McCleverty, J. E. White, "Cycloheptatrienemolybdenum(0) Tricarbonyl" Inorganic Syntheses 1967, volume 9, pp. 121–122. :C7H8 \+ Mo(CO)6 → (C7H8)Mo(CO)3 \+ 3 CO The compound is a piano stool complex, consisting of Mo(CO)3 bound to six carbon centers of the triene. The methylene group projects from the plane of the six coordinated carbon atoms.J. D. Dunitz and P. Pauling "Struktur des Cycloheptatrien- molybdän-tricarbonyls, C7H8Mo(CO)3" Helv. Chim.
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The Irvine graduate program was small and thus in his early work Overman frequently performed experiments himself, including his initial discovery of the Overman rearrangement. Palladium emerged as the metal of choice for this reaction, and this led to a long-term interest in palladium catalysis, including the palladium(II)-catalyzed Cope rearrangement, and later work on intramolecular cascading Heck reactions. Overman has performed many total syntheses of natural products, beginning with (±)-pumiliotoxin C (with Peter Jessup) in the late seventies. This interest was spurred on by a 1977 sabbatical visit by Samuel J. Danishefsky.
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A tetrahedral intermediate is a reaction intermediate in which the bond arrangement around an initially double-bonded carbon atom has been transformed from trigonal to tetrahedral. Tetrahedral intermediates result from nucleophilic addition to a carbonyl group. The stability of tetrahedral intermediate depends on the ability of the groups attached to the new tetrahedral carbon atom to leave with the negative charge. Tetrahedral intermediates are very significant in organic syntheses and biological systems as a key intermediate in esterification, transesterification, ester hydrolysis, formation and hydrolysis of amides and peptides, hydride reductions, and other chemical reactions.
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Butanone may be produced by oxidation of 2-butanol. The dehydrogenation of 2-butanol using a catalyst is catalyzed by copper, zinc, or bronze: :CH3CH(OH)CH2CH3 → CH3C(O)CH2CH3 \+ H2 This is used to produce approximately 700 million kilograms yearly. Other syntheses that have been examined but not implemented include Wacker oxidation of 2-butene and oxidation of isobutylbenzene, which is analogous to the industrial production of acetone. The cumene process can be modified to produce phenol and a mixture of acetone and butanone instead of only phenol and acetone in the original.
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One of the Institute's principal activities is the publication of the Archaeological Journal, an annual peer- reviewed journal containing reports of archaeological and architectural survey and fieldwork on sites and monuments of all periods, and syntheses and overviews of similar work throughout the British Isles. It also hosts lectures and seminars, and both sponsors and participates in field trips to archaeological sites and landscapes. It works in cooperation with other archaeological bodies and societies. A programme of monthly lectures is held from October to May at Burlington House, Piccadilly, London.
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Thermal shock synthesis (TSS) is a method in which materials are synthesized via rapid, high-temperature heating. In the TSS process, temperatures as high as 3000 K are applied for a duration of just seconds or milliseconds, followed by rapid cooling (a TSS image shown in Fig. 1). In this regard, TSS is distinct from conventional high-temperature syntheses that feature slow and near-equilibrium heating at limited temperature ranges (e.g., 1500 K for furnace heating) for extended periods of time (typically hours) and generally slow heating and cooling (~10 K/min).
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Later, it was shown that many other tissues secrete prostaglandins and that they perform a variety of functions. The first total syntheses of prostaglandin F2α and prostaglandin E2 were reported by E. J. Corey in 1969, an achievement for which he was awarded the Japan Prize in 1989. In 1971, it was determined that aspirin-like drugs could inhibit the synthesis of prostaglandins. The biochemists Sune K. Bergström, Bengt I. Samuelsson and John R. Vane jointly received the 1982 Nobel Prize in Physiology or Medicine for their research on prostaglandins.
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The material is usually prepared by the reaction of bromine with tantalum metal (or tantalum carbide) at elevated temperatures in a tube furnace. The bromides of the early metals are sometimes preferred to the chlorides because of the relative ease of handling liquid bromine vs gaseous chlorine. Like other molecular halides, it is soluble in nonpolar solvents such as carbon tetrachloride (1.465 g/100 mL at 30 °C), but it reacts with many other solvents.D. H. Nowicki, I. E. Campbell "Tantalum(V) Bromide" Inorganic Syntheses 1953, volume IV, p. 130.
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On an industrial scale, the reaction of acetic anhydride with hydrogen chloride produces a mixture of acetyl chloride and acetic acid: :(CH3CO)2O + HCl → CH3COCl + CH3CO2H A key industrial route to propionic anhydride involves thermal dehydration: :2 CH3CH2CO2H -> (CH3CH2CO)2O + H2O Another routes is the Reppe carbonylation of ethylene with propionic acid and nickel carbonyl as the catalyst: :CH2=CH2 \+ CH3CH2CO2H + CO -> (CH3CH2CO)2O Common syntheses of acyl chlorides also entail the reaction of carboxylic acids with phosgene, thionyl chloride, and phosphorus trichloride Phosphorus pentabromide is used for acyl bromides, which are rarely of value.
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His work in the Organic Chemical Manufactures unit gave him extensive experience in chemical preparation. Students were required to take careful notebook records of each preparation, including the cost of chemicals, apparatus, and the time needed. Marvel was known for his ability to modify poor procedures to make them more effective, and to describe procedures so that others could follow them. Many of these laboratory procedures were later published, first as pamphlets on Organic Chemical Reagents, by Roger Adams, O. Kamm, and C. S. Marvel, and later in the journal Organic Syntheses.
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The Court of Audit informs the various legislative assemblies and the provincial councils of the results of its audit missions. The Court of Audit submits its audit reports to the assemblees and councils in the form of syntheses integrated into the annual Book of comments (the so-called "blunder book") or in the form of special publications. The Court of Audit informs the legislative assemblies of the commitments, authorizations or payments of expenditures exceeding the budget appropriations and comments on the budget drafts submitted to the legislative assemblies.
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The compound was first prepared in low yield by the reduction of manganese iodide with magnesium under CO.Brimm, E. O.; Lynch, M. A.; Sesny, W. J. "Preparation and Properties of Manganese Carbonyl" Journal of the American Chemical Society 1954, volume 76, page 3831 - 3835. A more efficient preparation entails reduction of anhydrous MnCl2 with sodium benzophenone ketyl under 200 atmospheres of CO.King, R. B. Organometallic Syntheses. Volume 1 Transition-Metal Compounds; Academic Press: New York, 1965. The availability of inexpensive methylcyclopentadienyl manganese tricarbonyl ("MMT") has led to a low pressure route to Mn2(CO)10.
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These infants exhibit normal phenylalanine hydroxylase (PAH) enzymatic activity but have a deficiency in dihydropteridine reductase (DHPR), an enzyme required for the regeneration of tetrahydrobiopterin (THB or BH4), a cofactor of PAH. Less frequently, DHPR activity is normal but a defect in the biosynthesis of THB exists. In either case, dietary therapy corrects the hyperphenylalaninemia. However, THB is also a cofactor for two other hydroxylation reactions required in the syntheses of neurotransmitters in the brain: the hydroxylation of tryptophan to 5-hydroxytryptophan and of tyrosine to L-dopa.
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Thionyl fluoride can be produced by the reaction of thionyl chloride with fluoride sources such as antimony trifluoride.W. C. Smith, E. L. Muetterties "Thionyl Fluoride" Inorganic Syntheses 1960, Volume 6, pages: 162-163. :3 SOCl2 \+ 2SbF3 → 3SOF2 \+ 2SbCl3 Alternatively, it arises via the fluorination of sulfur dioxide: :SO2 \+ 2PF5 → SOF2 \+ POF3 Thionyl fluoride arises as a fleeting intermediate from the decomposition of sulfur hexafluoride as the result of electrical discharges which generate sulfur tetrafluoride. SF4 hydrolyzes to give thionyl fluoride, which in turn hydrolyzes further as described below.
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However, the increasing need of climate scientists for regional or global data syntheses to support their modelling activities requires automation of the data exchange process. Consequently, oceanographic data managers are developing 'virtual data centres' to support the distribution of data through software agents. Distributed data systems are critically dependent on machine- readable metadata to provide information on such issues as physical access protocols and semantics of the data. It is essential that this metadata conforms to agreed standards to prevent the computing paradigm of 'garbage in, garbage out' blighting automated data exchange.
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The other strand is the introduction of this approach into synthetic work, mainly in organic chemistry. Here the crucial breakthrough was achieved by Mayo, Pike and Butcher and by Williamson who demonstrated that inexperienced students were able to carry out organic syntheses on a few tens of milligrams, a skill previously thought to require years of training and experience. These approaches were accompanied by the introduction of some specialised equipment, which was subsequently simplified by Breuer without great loss of versatility. The text of the book is available in electronical format free from the author.
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His research interests lies in organometallic and heteroatom chemistry directed towards organic synthesis, synthetic methodology and reaction mechanisms, and organosilicon and organometallic chemistry, heterocyclic chemistry, and bio-organometallic chemistry. He is the author of more than 260 original papers and more than 50 review articles, and 22 books and book chapters. He found various synthetic reactions, e.g., the new transformation reaction from organosilicon compounds to organocopper reagents promoted by copper (I) salt, the "tailor-made" synthesis of non-stabilized 1,3-dipolar reagents, syntheses of the new lantanoid reagents and the ate-compounds of transition metals.
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Nicotine biosynthesis The biosynthetic pathway of nicotine involves a coupling reaction between the two cyclic structures that comprise nicotine. Metabolic studies show that the pyridine ring of nicotine is derived from niacin (nicotinic acid) while the pyrrolidine is derived from N-methyl-Δ1-pyrrollidium cation. Biosynthesis of the two component structures proceeds via two independent syntheses, the NAD pathway for niacin and the tropane pathway for N-methyl-Δ1-pyrrollidium cation. The NAD pathway in the genus Nicotiana begins with the oxidation of aspartic acid into α-imino succinate by aspartate oxidase (AO).
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Exposure to light is detrimental to the stability of aqueous solutions of psilocybin, and will cause it to rapidly oxidize—an important consideration when using it as an analytical standard. Osamu Shirota and colleagues reported a method for the large-scale synthesis of psilocybin without chromatographic purification in 2003. Starting with 4-hydroxyindole, they generated psilocybin from psilocin in 85% yield, a marked improvement over yields reported from previous syntheses. Purified psilocybin is a white, needle-like crystalline powder with a melting point between , and a slightly ammonia-like taste.
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Hydrazines are part of many organic syntheses, often those of practical significance in pharmaceuticals (see applications section), as well as in textile dyes and in photography. Hydrazine is used in the Wolff-Kishner reduction, a reaction that transforms the carbonyl group of a ketone into a methylene bridge (or an aldehyde into a methyl group) via a hydrazone intermediate. The production of the highly stable dinitrogen from the hydrazine derivative helps to drive the reaction. Being bifunctional, with two amines, hydrazine is a key building block for the preparation of many heterocyclic compounds via condensation with a range of difunctional electrophiles.
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Research Interests, Organic Chemistry Faculty, UCLA He has also developed chemical syntheses for a variety of natural products with antitumor and antiviral properties including tedanolides, oxetanocin, halomons, and xestobergsterol. Other research interests include the bridged Robinson annulation and the mixed Lewis acid Diels-Alder process.Current Research Interest, UCLA Jung's research group developed an antagonist of the androgen receptor enzalutamide, which is a pharmaceutical drug used for the treatment of hormone refractory prostate cancer."New Prostate Cancer Agent Class: Rational design leads to novel drug candidate, now in clinical trials", Chemical and Engineering News, September 22, 2008, Volume 86, Number 38 pp.
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He also served on the editorial board of Organic Syntheses from 1946 to 1954. He received the 1946 ACS Award in Pure Chemistry, given to the most promising young chemist, and presented "Some Polar Factors Affecting the Properties of Unsaturated Compounds" as his award address. Price was a pioneer in the field of polyethers. He invented polyether polyurethane rubber, a form of foam rubber which became widely used in sponges, mattresses, cars, insulation and building materials, flotation devices, and packaging. He obtained U.S. Patent 2,866,774 for elastomeric polyether urethanes (Filing Date: 09/23/1953; Publication Date: 12/30/1958).
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Vanadium(III) sulfate is the inorganic compound with the formula V2(SO4)3. It is a pale yellow solid that is stable to air, in contrast to most vanadium(III) compounds. It slowly dissolves in water to give the green aquo complex [V(H2O)6]3+. The compound is prepared by treating V2O5 in sulfuric acid with elemental sulfur:Robert T. Claunch, Mark M. Jones "Vanadium(III) Sulfate" Inorganic Syntheses, 1963, Volume 7, pages 92–94. :V2O5 \+ S + 3 H2SO4 → V2(SO4)3 \+ SO2 \+ 3 H2O This transformation is a rare example of a reduction by elemental sulfur.
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NMT has been synthesized in a number of ways. One of the earliest syntheses is that reported by Walpole, who made it by the following sequence of steps: (i) acetylation of 4-methoxyphenethylamine with acetic anhydride; (ii) methylation of the amide using Na/methyl iodide; (iii) cleavage of the methyl ether to the phenol using HI; (iv) hydrolysis of the N-acetyl group with aqueous HCl. Walpole also described an alternative, but similar sequence of reactions leading to NMT, beginning with the conversion of 4-methoxyphenethylamine to its benzenesulfonamide, which was then N-methylated and de-protected.G. S. Walpole (1910) J. Chem. Soc.
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The very thought of censoring any scientific publication would have been alien to Wilhelm Haidinger. In this regard, it must be remembered how Wilhelm Haidinger had allowed Adolph von Morlot to publish his accounts on the laboratory syntheses of dolomite first and foremost in Haidinger's own Berichte über die Mittheilungen von Freunden der Naturwissenschaften in Wien (at the same time Morlot's paper on the synthesis of dolomite appeared in four other well-known journals.Morlot, A. von (1847 B): Über Dolomit und seine künstliche Darstellung. Neues Jahrbuch für Mineralogie, Geognosie, Geologie und Petrefaktenkunde, 1847, pp.862-864.
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Perovskite NCs are promising materials for the emitting layer of light-emitting diodes (LEDs) as they offer potential advantages over organic LEDs (OLEDs) such as the elimination of precious metals (Ir, Pt) and simpler syntheses. The first report of green electroluminescence (EL) was from MAPbBr3 NCs although no efficiency values were reported. It was later observed that MAPbBr3 NCs could form in a polymer matrix when the precursors for MAPbBr3 thin films were mixed with an aromatic polyidmide precursor. The authors of this study obtained green EL with an external quantum efficiency (EQE) of up to 1.2%.
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First total synthesis of physostigmine Julian & Pikl (1935) Physostigmine has two stereocenters—the two carbons where the five-membered rings join together—so any attempt at the total synthesis must pay attention to obtaining the correct stereoisomer. The 71 syntheses of physostigmine yield 33 racemic mixtures and 38 products of a single enantiomer. The first total synthesis of physostigmine was achieved by Julian and Pikl in 1935. The main goal of Julian's formal physostigmine synthesis was to prepare the key compound (L)-eseroline (compound 10 in the adjacent diagram), the conversion of which to physostigmine would be straightforward.
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During the 1930s, partly because of his relationship with Jones, Finn worked for the federal government, and later his firm performed contract work for federal agencies. His public buildings included federal buildings, a college administration building and a complex of dormitories, and he designed the San Jacinto Monument. He was one of the leaders in the development of the Art Deco style in Texas, though his work reflects a wide range of styles and syntheses. Along with Joseph Finger, Finn was one of the two leading architects in Houston during the first half of the twentieth century.
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Ferrous chloride is prepared by addition of iron powder to a solution of hydrochloric acid in methanol. This reaction gives the methanol solvate of the dichloride, which upon heating in a vacuum at about 160 °C converts to anhydrous FeCl2. The net reaction is shown: : Fe + 2 HCl → FeCl2 \+ H2 FeBr2 and FeI2 can be prepared analogously. An alternative synthesis of anhydrous ferrous chloride is the reduction of FeCl3 with chlorobenzene: :2 FeCl3 \+ C6H5Cl → 2 FeCl2 \+ C6H4Cl2 \+ HCl In one of two classic syntheses of ferrocene, Wilkinson generated FeCl2 in situ by comproportionation of FeCl3 with iron powder in THF.
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Ian Fleming (born 1935) is an English organic chemist, and an emeritus professor of the University of Cambridge, and an emeritus fellow of Pembroke College, Cambridge. He was the first to determine the full structure of chlorophyll (in 1967) and was involved in the development of the synthesis of cyanocobalamin by Robert Burns Woodward. He has made major contributions to the use of organosilicon compounds for stereospecific syntheses; reactions which have found application in the synthesis of natural compounds. He is also a prolific author, and has written a number of textbooks, encyclopedia chapters and influential review articles.
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Longares Alonso 1974 dedicates 40 pages to rural issues discussed during the Cortes and 7 (last) pages to dynastical question. In some syntheses the 1789 debate is not at all noted in chapters dedicated to Carlos IV, only briefly referred to when discussing the 1830 document of Fernando VII.perhaps the best example is a monumental series Historia de España Memendez Pidal; the volume dedicated to the reign of Carlos IV did not mention the 1789 debate, which was only briefly referred when discussing the 1830 regulations, compare José María Jover Zamora (ed.), Historia de España, vol. XXXII, Madrid 1992, , p. 925.
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In molecular biology, the polyketide synthesis cyclase family of proteins includes a number of cyclases involved in polyketide synthesis in a number of actinobacterial species. Aromatic polyketides are assembled by a type II (iterative) polyketide synthase in bacteria. Iterative type II polyketide syntheses produce polyketide chains of variable but defined length from a specific starter unit and a number of extender units. They also specify the initial regiospecific folding and cyclisation pattern of nascent polyketides either through the action of a cyclase (CYC) subunit or through the combined action of site-specific ketoreductase and CYC subunits.
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Attempted syntheses of perbromates were unsuccessful until 1968, when it was finally obtained by the beta decay of selenium-83 in a selenate salt: : → + β− Subsequently, it was successfully synthesized again by the electrolysis of , although only in low yield. Later, it was obtained by the oxidation of bromate with xenon difluoride. Once perbromates are obtained, perbromic acid can be produced by protonating . One effective method of producing perbromate is by the oxidation of bromate with fluorine under alkaline conditions: : + + 2 → + 2 + This synthesis is much easier to perform on a large scale than the electrolysis route or oxidation by xenon difluoride.
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He served as a prorector of the University of Zagreb after his rectorship mandate expired (1950–1951). He was a significant contributor to modern Croatian literary theory, especially in the position of Croatian literature in the European context. He published numerous monographies on top Croatian artists such as Nazor, Šenoa, Vidrić or Mažuranić, a number of critic-essayist writings on lesser known writers, as well as great syntheses on Croatian literary criticism of the 19th century, and the unfinished history of Croatian literature from Croatian National Revival to the time of creation of Yugoslavia. A square in Novi Zagreb is named after him.
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A recent report by Snyder and coworkers uses almost identical reductive Heck conditions to construct a quaternary center en route to the conidiogenone natural products. In the Carreira synthesis of (±)-gelsemoxonine, a diastereoselective reductive Heck cyclization was used to form a key oxindole ring in 72% yield as a single diastereomer. Notably, the reductive Heck conditions avoid undesired side reactivity including β-hydride elimination, destruction of the adjacent azetidine ring, and cleavage of the N−O and oxabicyclic C−O bonds. Application of the reductive Heck reaction in the total syntheses of ibogaine, ambiguine H, hapalindole U, and (±)-gelsemoxonine.
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William Wyvill Fitzhugh IV is an American archaeologist and anthropologist who directs the Smithsonian’s Arctic Studies Center and is a Senior Scientist at the National Museum of Natural History. He has conducted archaeological research throughout the circumpolar region investigating cultural responses to climate and environmental change and European contact. He has published numerous books and more than 150 journal articles, and has produced large international exhibitions and popular films. Of particular note are the many exhibition catalogues he has had edited, which make syntheses of scholarly research on these subjects available to visitors to public exhibitions.
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In 1893, Methamphetamine was first synthesised from ephedrine by Nagayoshi Nagai and in 1919, Akira Ogata was the first to synthesise methamphetamine in a crystallized form. Ogata blended the red phosporus and ephedrine, which is derived from an Asian herbal plant, to produce an amphetamine that could be dissolved in water. The procedure involved reduction of ephedrine using iodine and red phosphorus. Ogata's synthesis of methamphetamine replaced much more complicated earlier syntheses, and continues to be used as the basis for modern production and usage of the drug.. Particularly, is the method favored in illegal drug production.
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Asymmetric induction by the molecular framework of an acyclic substrate is the idea that asymmetric steric and electronic properties of a molecule may determine the chirality of subsequent chemical reactions on that molecule. This principal is used to design chemical syntheses where one stereocentre is in place and additional stereocentres are required. When considering how two functional groups or species react, the precise 3D configurations of the chemical entities involved will determine how they may approach one another. Any restrictions as to how these species may approach each other will determine the configuration of the product of the reaction.
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Allopumiliotoxins are very biologically useful but are rare in nature. For this reason, many groups have researched syntheses for various alkaloids of this type. The main problem with allopumiliotoxin synthesis arises from the alkylidene side chain because the stereochemistry of it can be difficult to control by Wittig-type functionalizations. Total synthesis of (+)-allopumiliotoxin 267A was achieved using a chiral dihydropyridone intermediate that was formed from the addition of ethyl lithiopropiolate to the N-acylpyridinium salt which results from the reaction of (+)-trans-2-(α-cumyl)cyclohexyl chloroformate and 4-methoxy-3-methyl-5(triisopropylsilyl)pyridine.
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Computer models of ocean circulation increasingly place most of the deep upwelling in the Southern Ocean, associated with the strong winds in the open latitudes between South America and Antarctica. While this picture is consistent with the global observational synthesis of William Schmitz at Woods Hole and with low observed values of diffusion, not all observational syntheses agree. Recent papers by Lynne Talley at the Scripps Institution of Oceanography and Bernadette Sloyan and Stephen Rintoul in Australia suggest that a significant amount of dense deep water must be transformed to light water somewhere north of the Southern Ocean.
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Deyermond's published output was prodigious – 40 books, written or edited, and almost 200 articles ranging through four centuries of medieval Hispanic literature. He recognised that a comprehensive study of Medieval literature would require several tooks which exist for studies in English but which were lacking for Spanish. He particularly lamented the lack of complete dictionaries, bibliographies and historical syntheses; as a result he authored the medieval volume for the Ernest Benn History of Spanish Literature (1969), which addressed the lack of an historical synthesis. His volumes of History and Criticism of Spanish Literature (1980 and 1991) carry an in-depth bibliography.
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500px Most biological molecules and pharmaceutical targets exist as one of two possible enantiomers; consequently, chemical syntheses of natural products and pharmaceutical agents are frequently designed to obtain the target in enantiomerically pure form. Chiral auxiliaries are one of many strategies available to synthetic chemists to selectively produce the desired stereoisomer of a given compound. Chiral auxiliaries were introduced by Elias James Corey in 1975 with chiral 8-phenylmenthol and by Barry Trost in 1980 with chiral mandelic acid. The menthol compound is difficult to prepare and as an alternative trans-2-phenyl-1-cyclohexanol was introduced by J. K. Whitesell in 1985.
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In the same way that SbF5 enhances the Brønsted acidity of HF, it augments the oxidizing power of F2. This effect is illustrated by the oxidation of oxygen:Shamir, J.; Binenboym, J. "Dioxygenyl Salts" Inorganic Syntheses 1973, XIV, 109-122. :2 SbF5 \+ F2 \+ 2 O2 → 2 [O2]+[SbF6]− Antimony pentafluoride has also been used in the first discovered chemical reaction that produces fluorine gas from fluoride compounds: :4 + 2 → 4 + 2 + The driving force for this reaction is the high affinity of SbF5 for , which is the same property that recommends the use of SbF5 to generate superacids.
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Because there exist multiple classes of natural products containing eight-membered rings, the syntheses of which having proved difficult, the anionic oxy-Cope rearrangement has been highlighted as a suitable alternative pathway. Its application here offers great stereochemical control, and its use is far more general than the relatively unsuccessful routes that had been employed before its development. 596x596px In spite of possible geometrical constraints, the required unsaturated substrates may contain triple bonds in place of either of the double bonds. Such an alkynol was effectively manipulated in the elegant synthesis of both poitediol and dactylol.
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The synthesis was completed in a significantly lower number of steps than had ever been achieved before, made possible in part by Krische's use of his allylation methods. This is shown in the scheme below. Krische allylation applied to the syntheses of (+)-roxaticin The synthetic utility of these methods is also shown in Krische's synthesis of bryostatin 7, a more efficient synthesis than those of Hale (2008), Keck (2013), Masamune (1990), and others. Krische allylation in Krische's bryostatin 7 synthesis In 2012, De Brabander applied the Krische bisallylation to his synthesis of psymberin in 17 LLS and 32 total steps, as shown below.
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Thus, this reaction can be classified as a C-H activation reaction, an oxidative Heck reaction, and a C-H olefination. Surprisingly, the Fujiwara–Moritani reaction was discovered before the Heck reaction. The need for prefunctionalization of either component is obviated in this reaction, which is desirable because it can shorten syntheses, provide atom economical routes, and enable late stage functionalization of complex molecules. Despite the potential of the Fujiwara- Moritani transformation, it is not often utilized by organic chemists due to the typically harsh reaction conditions, such as acidic, oxidative and high temperature conditions, that most functional groups can not survive.
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An example of this procedure is the reaction of 2,2,6-trimethylcyclohexanone to the hydrazone by reaction with hydrazine and triethylamine in ethanol at reflux followed by reaction of the hydrazone with iodine in the presence of 2-tert-butyl-1,1,3,3-tetramethylguanidine (cheaper than DBU) in diethyl ether at room temperature.Preparation and reactions of 2-tert-butyl-1,1,3,3-tetramethylguanidine: 2,2,6-trimethylcyclohexen-1-yl iodide Derek H. R. Barton, Mi Chen, Joseph Cs. Jászberényi, and Dennis K. Taylor Organic Syntheses, Coll. Vol. 9, p.147 (1998); Vol. 74, p.101 (1997) Article Another example can be found in the Danishefsky Taxol total synthesis.
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RuCl2(PPh3)3 is the product of the reaction of ruthenium trichloride trihydrate with a methanolic solution of triphenylphosphine.Stephenson, T. A.; Wilkinson, G. "New Complexes of Ruthenium (II) and (III) with Triphenylphosphine, Triphenylarsine, Trichlorostannate, Pyridine, and other Ligands", J. Inorg. Nucl. Chem., 1966, 28, 945-956. P. S. Hallman, T. A. Stephenson, G. Wilkinson "Tetrakis(Triphenylphosphine)Dichloro-Ruthenium(II) and Tris(Triphenylphosphine)-Dichlororuthenium(II)" Inorganic Syntheses, 1970 Volume 12, . :2 RuCl3(H2O)3 \+ 7 PPh3 → 2 RuCl2(PPh3)3 \+ 2 HCl + 5 H2O + OPPh3 The coordination sphere of RuCl2(PPh3)3 can be viewed as either five- coordinate or octahedral.
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He was among the earliest to use carbon-14 as a tracer in the study of reaction mechanisms and molecular rearrangements. He has been a leader in the use of NMR to establish mechanisms and structures particularly in demonstrating the fluxional nature of Grignard reagents and related molecules and in the observation of a symmetry in organic chemistry." # Elias J. Corey 1984 "For outstanding research in the synthesis of organic compounds, particularly the total synthesis of highly complex natural products such as prostaglandins, alkaloids, giberellic acid, hormones, toxins, triterpenes, and others. Many of these syntheses are considered to be milestones in their fields.
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In the United States it was withdrawn in 1982 and made a Schedule I drug in 1984. It has a DEA ACSCN of 2565 and in 2013 the aggregate annual manufacturing quota for the United States was 10 grams. Mention of its possible use in some types of cancer and AIDS treatments has periodically appeared in the literature since the late 1980s; research does not appear to have reached an advanced stage. The DEA has also added the methaqualone analogue mecloqualone (also a result of some incomplete clandestine syntheses) to Schedule I as ACSCN 2572, with zero manufacturing quota.
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Hexamethylbenzene is typically prepared in the gas phase at elevated temperatures over solid catalysts. An early approach to preparing hexamethylbenzene involved reacting a mixture of acetone and methanol vapours over an alumina catalyst at 400 °C. Combining phenols with methanol over alumina in a dry carbon dioxide atmosphere at 410–440 °C also produces hexamethylbenzene, though as part of a complex mixture of anisole (methoxybenzene), cresols (methylphenols), and other methylated phenols. An Organic Syntheses preparation, using methanol and phenol with an alumina catalyst at 530 °C, gives approximately a 66% yield, though synthesis under different conditions has also been reported.
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CPT showed remarkable anticancer activity in preliminary clinical trials especially against breast, ovarian, colon, lung, and stomach cancers However, it has low solubility and adverse effects have been reported when used therapeutically, so synthetic and medicinal chemists have developed numerous syntheses of camptothecin and various derivatives to increase the benefits of the chemical, with good results. Four CPT analogues have been approved and are used in cancer chemotherapyTakimoto CH, Calvo E. "Principles of Oncologic Pharmacotherapy" in Pazdur R, Wagman LD, Camphausen KA, Hoskins WJ (eds.) Cancer Management: A Multidisciplinary Approach. 11 ed. 2008. today, topotecan, irinotecan, belotecan, and trastuzumab deruxtecan.
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However, using chlorine or bromine as the oxidising agent also produces hydrochloric or hydrobromic acid as a side-product, which needs to be removed from the solution since they can reduce the selenic acid to selenous acid. Another method of preparing selenic acid is by the oxidation of elemental selenium in a water suspension by chlorine: :Se + 4 + 3 → + 6 HCl To obtain the anhydrous acid as a crystalline solid, the resulting solution is evaporated at temperatures below in a vacuum.Seppelt, K. “Selenoyl difluoride” Inorganic Syntheses, 1980, volume XX, pp. 36-38. . The report describes the synthesis of selenic acid.
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Recent studies suggested that the function the non-canonical NF-κB pathway is modulated by canonical NF-κB signalling. For example, syntheses of the constituents of the non-canonical pathway, viz RelB and p52, are controlled by canonical IKK2-IκB-RelA:p50 signalling. Moreover, generation of canonical and non-canonical dimers, viz RelA:p50 and RelB:p52, within the cellular milieu are mechanistically interlinked. These analyses suggest that an integrated NF-κB system network underlies activation of both RelA and RelB containing dimer and that a malfunctioning canonical pathway will lead to an aberrant cellular response also through the non-canonical pathway.
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The New Age has also been identified by various scholars of religion as part of the cultic milieu. This concept, developed by the sociologist Colin Campbell, refers to a social network of marginalised ideas. Through their shared marginalisation within a given society, these disparate ideas interact and create new syntheses. Hammer identified much of the New Age as corresponding to the concept of "folk religions" in that it seeks to deal with existential questions regarding subjects like death and disease in "an unsystematic fashion, often through a process of bricolage from already available narratives and rituals".
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Boris von Rohdendorf Boris Borissovich Rohdendorf (12 July 1904 - 21 November 1977) was a Russian entomologist and curator at the Zoological Museum at the University of Moscow. He attained the position of head of the Laboratory of Arthropods, Paleontological Institute of Russian Academy of Sciences, Academy of Sciences of the USSR (now Russian Academy of Sciences) in Moscow. A student of Andrey Martynov, he was a prolific taxonomist who described numerous new taxa, including fossil Diptera, and published important syntheses on fossil insects. His work is being extensively revised by the current generation of Russian paleoentomologists.
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Oxymercuration reductionOrganic Syntheses OS 6:766 LinkThe oxymercuration reaction is an electrophilic addition organic reaction that transforms an alkene into a neutral alcohol. In oxymercuration, the alkene reacts with mercuric acetate (AcO–Hg–OAc) in aqueous solution to yield the addition of an acetoxymercury (HgOAc) group and a hydroxy (OH) group across the double bond. Carbocations are not formed in this process and thus rearrangements are not observed. The reaction follows Markovnikov's rule (the hydroxy group will always be added to the more substituted carbon) and it is an anti addition (the two groups will be trans to each other).
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Overman has also worked extensively on the aza-Cope-Mannich reaction, originally designed to solve a stereoelectronic problem in the total synthesis of gephyrotoxin. :an Aza-Cope Mannich cascade reaction This reaction is described by Overman as "robust", and was subsequently used in the total syntheses of several natural products, for example (–)-strychnine. A ring-enlarging version of the reaction was used in the synthesis of secondary metabolites such as actinophyllic acid. A related reaction, a Prins-Pinacol cascade which produces a tetrahydrofuran, has also been used extensively by the Overman group, for example in the total synthesis of (–)-magellanine, a Lycopodium alkaloid.
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Bulky pyrazolyl borates can be prepared from 3,5-disubstituted pyrazoles, such as the dimethyl derivative. These bulky pyrazolyl borates have proven especially valuable in the preparation of catalysts and models for enzyme active sites. Utilizing scorpionate ligands in the syntheses of metal catalysts may allow simpler and more accurate methods to be developed. Ligands allow for good shielding of the bound metal while strong sigma bonds between the nitrogens and the metal stabilize the metal; these attributes help scorpionate compounds with creating highly symmetrical supramolecular silver complexes and olefin polymerization (with the compound hydrotris(pyrazolyl) borate Mn).
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In Northern Europe, however, such artists, and such an audience, could hardly be found. The prevailing style remained Gothic, and different syntheses of this and Italian styles were made in the first decades of the 16th century by more internationally aware artists such as Albrecht Dürer, Hans Burgkmair and others in Germany, and the misleadingly named school of Antwerp Mannerism, in fact unrelated to, and preceding, Italian Mannerism.The term is also sometimes used in architecture to describe a different style, which is Mannerist. The painting style is mostly found before about 1520, the architectural one after about 1540.
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Apart from increasing RNA stability, this modification is also involved in regulation of translation. All eukaryotic stop codons contain one uridine (UAA, UGA and UGA); conversion of this uridine to pseudouridine results in suppression of translational termination and generation of unexpected sense codons. The artificial process of pseudouridylation has an effect on the function of mRNA: it changes the genetic code by making non-canonical base pairing possible in the ribosome decoding center. Pseudouridylation reactions are catalyzed by enzymes that contain the pseudouridine synthase domain; 13 such enzymes have been identified in humans, which are called pseudouridine syntheses (PUS).
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More specifically some of its important reactions include treatments with 2'-deoxyribonucleoside phosphorylase, methyltransferase, or nucleoside phosphorylase, affording the corresponding 5'-phosphate, giving rise to no methylation at its 5-position, or no cleavage of the glycosyl bond in contrast to 5-fluoro-2'-deoxyuridine,Duschinsky, R.; Pleven, E.; Malvica, J. Heidelberger, C. Abstr. 132nd Meeting, Am. Chem. Soc., 1957, p. 19-C. respectively. This earlier work gave impetus to further synthetic studies on the nucleosides with the β-D-arabinofuranosyl moiety including Vidarabine,Glaudemans, C. P. J.; Fletcher, Jr., H. G. Syntheses with Partially Benzylated Sugars.
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He is also affiliated with the university's Mentored Research Program in Space Life Sciences, where he examines nutrition issues related to space travel and skeletal muscle metabolism. Much of Wu's research has focused on amino acid biochemistry and nutrition in animals, including the arginine- nitric oxide pathway, as well as the syntheses of the arginine-family of amino acids (including arginine, citrulline, glutamate, glutamine, and proline) and glycine in mammals, birds and fish. He recently proposed two important new concepts in nutrition: functional amino acids and dietary requirements of animals for synthesizable amino acids. In 2012, Wu was elected Fellow of the AAAS.
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The mechanism involves complexation of iron(III) into the hydroxyl, followed by a radical coupling reaction of the naphthol rings initiated by iron(III) reducing into iron(II). Optically active BINOL can also be obtained from racemic BINOL by optical resolution. In one method, the alkaloid N-benzylcinchonidinium chloride forms a crystalline inclusion compound. The inclusion compound of the (S)-enantiomer is soluble in acetonitrile but that of the (R)-enantiomer is not."RESOLUTION OF 1,1'-BI-2-NAPHTHOL" , Dongwei Cai, David L. Hughes, Thomas R. Verhoeven, and Paul J. Reider, in Organic Syntheses Coll. Vol.
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In this position, Anderson directed progressively larger survey and excavation projects in the southeast and southwest. In 1983 Anderson enrolled in the University of Michigan anthropology doctoral program, where he spent the next three years on campus taking courses. After his classwork was completed in 1986, Anderson took a job with another CRM company, Garrow and Associates, in Atlanta, Georgia. With Garrow and associates, Anderson directed a major survey project in northeast Arkansas, examining approximately of the L'Anguille River channel margin, and also wrote two major archaeological syntheses, of the Richard B. Russell Multiple Resource Area CRM program (with J. W. Joseph).
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He had considerable freedom, set up a large international group, and was made a Fellow of Churchill College. Nonetheless, he was not happy at Cambridge and transferred in 1967 to University College London. In May of that year he was elected a Fellow of the Royal Society. His membership citation read: Professor Sondheimer is distinguished for his work on the total synthesis of a range of natural products, the partial synthesis of steroid hormones and analogues, and especially for his syntheses of the hitherto unknown class of conjugated unsaturated macrocyclic compounds which has led to some interesting theoretical conclusions.
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The longue durée (; ) is an expression used by the French Annales School of historical writing to designate their approach to the study of history. It gives priority to long-term historical structures over what François Simiand called histoire événementielle ("evental history", the short-term time-scale that is the domain of the chronicler and the journalist), concentrating instead on all-but-permanent or slowly evolving structures, and substitutes for elite biographies the broader syntheses of prosopography. The crux of the idea is to examine extended periods of time and draw conclusions from historical trends and patterns.
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Harry Belafonte, a Jamaican-American pop-calypso singer Caribbean music genres are diverse. They are each syntheses of African, European, Indian and Indigenous influences, largely created by descendants of African slaves (see Afro-Caribbean music), along with contributions from other communities (such as Indo-Caribbean music). Some of the styles to gain wide popularity outside the Caribbean include, bachata, merenque, palo, mombo, denbo, baithak gana, bouyon, cadence-lypso, calypso, chutney, chutney-soca, compas, dancehall, jing ping, parang, pichakaree, punta, ragga, reggae, reggaeton, salsa, soca, and zouk. Caribbean is also related to Central American and South American music.
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This work amounted to a partial synthesis of vitamin B12 from a natural product containing all the structural elements of vitamin B12 except the nucleotide loop. Therefore, cobyric acid was chosen as the target molecule for a total synthesis of vitamin B12. Collaborative work of research groups at Harvard and at ETH resulted in two cobyric acid syntheses, both concomitantly accomplished in 1972, one at Harvard, and the other at ETH. A "competitive collaboration" of that size, involving 103 graduate students and postdoctoral researchers for a total almost 177 man- years, is so far unique in the history of organic synthesis.
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Neil K. Garg is currently a professor of chemistry and holds the Kenneth N. Trueblood Endowed Chair at the University of California, Los Angeles. Garg's research is focused on the chemical synthesis of organic compounds, with an emphasis on the development of new strategies for the preparation of complex molecules possessing unique structural, biological, and physical properties. His group has made breakthroughs in catalysis and in the understanding and utilization of strained intermediates, such as arynes, cyclic alkynes, and cyclic allenes. His laboratory has completed the total syntheses of many natural products, including welwitindolinones, akuammilines, and tubingensin alkaloids.
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Jiadifenolide has been the subject of synthetic study in several academic labs. The first total synthesis, reported in 2009, employed an asymmetric Robinson annulation and a translactonization reaction to construct the core of the molecule. Two further syntheses, a chiral-pool approach from (+)-pulegone and a racemic synthesis relying on a samarium diiodide-mediated reductive cyclization, were reported almost simultaneously in 2014. A second chiral-pool synthesis (from (+)-citronellal) reported in 2015 shortened the synthetic sequence, with a double Michael addition as the key transformation of eight steps, allowing the synthesis of gram-scale quantities of jiadifenolide.
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When the Pictet–Spengler reaction is performed with an aldehyde other than formaldehyde, a new chiral center is created. Several substrate- or auxiliary- controlled diastereoselective Pictet–Spengler reactions have been developed.a) The intermolecular Pictet-Spengler condensation with chiral carbonyl derivatives in the stereoselective syntheses of optically-active isoquinoline and indole alkaloids Enrique L. Larghi, Marcela Amongero, Andrea B. J. Bracca, and Teodoro S. Kaufman Arkivoc (RL-1554K) pp 98–153 2005 (Online Review); b) Teodoro S. Kaufman “Synthesis of Optically-Active Isoquinoline and Indole Alkaloids Employing the Pictet-Spengler Condensation with Removable Chiral Auxiliaries Bound to Nitrogen”. in “New Methods for the Asymmetric Synthesis of Nitrogen Heterocycles”; Ed.: J. L. Vicario. .
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In 1914 she became Assistant Director of the Antitoxin Laboratories, Toronto, and this led to her return to the UK with an appointment at the Lister Institute and research facilities at the Physiological Institute, University of London. While at Newnham College, Homer published on physical organic chemistry, including organic chemistry syntheses that involved the Friedel-Crafts reaction. Initially, she was advised by Humphrey Jones and also John Edward Purvis. The latter was a spectroscopist and assistant to George Downing Liveing at University of Cambridge but developed an interest in public health, becoming Lecturer in Chemistry and Physics in their application to Hygiene and Preventive Medicine in 1908.
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An aldol condensation is a condensation reaction in organic chemistry in which an enol or an enolate ion reacts with a carbonyl compound to form a β-hydroxyaldehyde or β-hydroxyketone (an aldol reaction), followed by dehydration to give a conjugated enone. Aldol condensation overview Aldol condensations are important in organic synthesis, because they provide a good way to form carbon–carbon bonds. For example, the Robinson annulation reaction sequence features an aldol condensation; the Wieland–Miescher ketone product is an important starting material for many organic syntheses. Aldol condensations are also commonly discussed in university level organic chemistry classes as a good bond-forming reaction that demonstrates important reaction mechanisms.
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E1 is similar to COOH-terminal domain of the Simian virus 40, plays a role in viral DNA replication maintaining plasmids within a cell. Results have found that CRPV and BPV1 are found in the same location of the genome, which indicates that papillomaviruses likely have similar methods of replicating their genomes outside of a chromosome. A notable difference between the genomes of the four strains is that the E6 protein is almost twice as long in the CRPV as in any of the other strains of papillomaviruses. The E6 protein is somewhat homologous with a family of ATP syntheses that are found in mitochondria of cattle.
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BjF consists of two naphthalene-like structures which are fused by a cyclopentane structure. This cyclopentane is not included in the aromaticity of the molecule. BjF can be obtained when either 2-(1-chloroethenyl)benzo[c]phenanthrene or 6-(1-chloroethenyl)chrysene is treated by flash vacuum thermolysis (FVT) at high temperatures (above 900 °C) followed by ring rearrangements (ring contraction/expansion) to selectively yield BjF.M. Sarobe et al. (1 January 1997) "High temperature gas phase syntheses of C20H12 cyclopenta-fused polycyclic aromatic hydrocarbons: benz[l]acephenanthrylene and benz[j]acephenanthrylene and their selective rearrangement to benzo[j]fluoranthene" Journal of the Chemical Society, Perkin Trans.
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Curran has held various positions in the American Chemical Society (ACS) Division of Organic Chemistry hierarchy, culminating as Chair of the Division in 2000. He was an Associate Editor of Organic Reactions from 1991–2001 and Editor of Tetrahedron Letters from 1995–2001. He is a member of Organic Syntheses, Inc and edited Volume 83 in 2006. He was a member of the Executive Committee of the symposium "Gomberg•2000, A Century of Radical Chemistry",Gomberg•2000, A Century of Radical Chemistry and he spearheaded the presentation on June 25, 2000 of an ACS National Chemical Landmark to the University of Michigan for Gomberg's 1900 discovery of organic free radicals.
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Reduction with zinc gives the dimer of bis(cyclopentadienyl)titanium(III) chloride in a solvent-mediated chemical equilibrium: center Cp2TiCl2 is a precursor to TiII derivatives. Reductions have been investigated using Grignard reagent and alkyl lithium compounds. More conveniently handled reductants include Mg, Al, or Zn. The following syntheses demonstrate some of the compounds that can be generated by reduction of titanocene dichloride in the presence of π acceptor ligands: :Cp2TiCl2 \+ 2 CO + Mg → Cp2Ti(CO)2 \+ MgCl2 :Cp2TiCl2 \+ 2 PR3 \+ Mg → Cp2Ti(PR3)2 \+ MgCl2 Alkyne derivatives of titanocene have the formula (C5H5)2Ti(C2R2) and the corresponding benzyne complexes are known. One family of derivatives are the titanocyclopentadienes.
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However, when this isotope is indirectly synthesized from the decay of 277Cn, only alpha particles with energy 9.21 MeV have been observed, indicating that this decay occurs from an isomeric level. Further research is required to confirm this. ;267Hs 267Hs is known to decay by alpha decay, emitting alpha particles with energies of 9.88, 9.83, and 9.75 MeV. It has a half-life of 52 ms. In the recent syntheses of 271Ds and 271mDs, additional activities have been observed. A 0.94 ms activity emitting alpha particles with energy 9.83 MeV has been observed in addition to longer lived ~0.8 s and ~6.0 s activities.
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In early 1969, Negoiţescu, newly readmitted into the Writers' Union, was assigned an apartment on Bucharest's Calea Victoriei. In December of the same year, the authorities threatened to confiscate the Negoiţescu's citing a juridical rationale he viewed as untenable, and, as a result, he initiated a formal gesture of protest. Despite the rising negative reactions against his work, Negoiţescu continued to publish essays and monographs: Însemnări critice ("Critical Records", 1970), E. Lovinescu (1970), ("Aladdin's Lamp", 1971), ("Engrams", 1975), Analize şi sinteze ("Analyses and Syntheses", 1976). These books occasionally transgressed the limits imposed by communist leaders, and sparked several of his more or less severe clashes with censorship.
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Moreover, different mouse strains can express contradicting results, even though they are both fed with same protein and carbohydrate ratios. In addition to protein, Fructose, a carbohydrate, has impact on fat deposition, plasma insulin, leptin, thyroid, estradiol, and corticosterone levels, lipogenesis, and lipolysis in the adipose tissue of the rat. "Glucose-sweetened beverages," however, did not caused as significant influence as "fructose-sweetened beverages" in promoting visceral adipose, gaining weight, interrupting lipid syntheses, and damaging lipoprotein rebuilding process. Given the diversity in human food and each human individually distinguished metabolic capacity, the results of testing the diet induce obesity in rodents are limited in term of translatability.
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He has pursued the application of photovoltaic polymers to solar energy, and was instrumental in forming the Victorian Organic Solar Cell Consortium. He has also continued to develop new syntheses of novel, biologically-useful materials. An example is his groups' synthesis of phosphoinositides, amphiphilic phospholipids situated in the cell membrane, which collaborators at the Ludwig Institute for Cancer Research have used to probe the dynamics of signal transduction (intercellular signalling being an important component of many aspects of cell biology, including that of tumors). Holmes has served on the editorial or advisory boards of numerous learned scientific journals, including Organic Letters, Chemical Communications and Angewandte Chemie.
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The Sylloge's natural emphasis is on Anglo-Saxon numismatics. Loyn's mastery of an extensive and specialised literature in an often-contentious area of history produced over four decades a series of cautious, even conservative syntheses of continuity and evolving changes in late Anglo-Saxon and Anglo-Norman England, universally well received in the academic press, which are still staples of student reading-lists. Aside from numerous articles, occasional lectures such as The "matter of Britain": A historian's perspective (a Creighton Trust lecture), and his main publications (see below), he edited The Middle Ages: A Concise Encyclopedia. He has been praised for his "felicitous, economic writing style"C.
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Kuhn's grave in Heidelberg Kuhn's areas of study included: investigations of theoretical problems of organic chemistry (stereochemistry of aliphatic and aromatic compounds; syntheses of polyenes and cumulenes; constitution and colour; the acidity of hydrocarbons), as well as extensive fields in biochemistry (carotenoids; flavins; vitamins and enzymes). Specifically, he carried out important work on vitamin B2 and the antidermatitis vitamin B6. In 1929 he became Principal of the Institute for Chemistry at the newly founded Kaiser Wilhelm Institute for Medical Research (which, since 1950, has been renamed the Max Planck Institute for Medical Research in Heidelberg). By 1937 he also took over the administration of this Institute.
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One proposal, by Linda Medlin and co-workers commencing in 2004, is for some of the centric diatom orders considered more closely related to the pennates to be split off as a new class, Mediophyceae, itself more closely aligned with the pennate diatoms than the remaining centrics. This hypothesis—later designated the Coscinodiscophyceae-Mediophyceae- Bacillariophyceae, or Coscinodiscophyceae+(Mediophyceae+Bacillariophyceae) (CMB) hypothesis—has been accepted by D.G. Mann among others, who uses it as the basis for the classification of diatoms as presented in Adl. et al.'s series of syntheses (2005, 2012, 2019), and also in the Bacillariophyta chapter of the 2017 Handbook of the Protists edited by Archibald et al.
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Because thromboxanes play a role in vasoconstriction and platelet aggregation, their dominance can disrupt vascular homeostasis and cause thrombotic vascular events. Furthermore, the importance of thromboxanes and their syntheses in vascular homeostasis is illustrated by findings that patients whose platelets were unresponsive to TXA displayed hemostatic defects and that a deficiency of platelet TXA production led to bleeding disorders. Furthermore, it has been found that the expression of TXA synthase may be of critical importance to the development and progression of cancer. An overall increase in TXA synthase expression has been observed in a variety of cancers, such as papillary thyroid carcinoma, prostate cancer, and renal cancer.
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The building block approach to drug discovery changed the landscape of chemical industry which supports medicinal chemistry. Major chemical suppliers for medicinal chemistry like Maybridge, Chembridge, Enamine adjusted their business correspondingly. By the end of the 1990th the use of building block collections prepared for fast and reliable construction of small-molecule sets of compounds (libraries) for biological screening became one of the major strategies for pharmaceutical industry involved in drug discovery; modular, usually one-step synthesis of compounds for biological screening from building blocks turned out to be in most cases faster and more reliable than multistep, even convergent syntheses of target compounds. There are online web-resources.
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Barrels outline circular structures in the 37.5-acre (17.4 ha) plaza at Poverty Point Poverty Point was not constructed all at once. The final form appears to have been the product of successive generations over a considerable period of time. The exact sequence and timeframe of earthwork construction is not precisely known. Radiocarbon dating of the site has produced a wide variety of results, but recent syntheses suggest earthwork construction began as early as 1800 BC and continued until as late as 1200 BC.Connolly, Robert P. "An Assessment of Radiocarbon Age Results from the Poverty Point Site". 2006. Louisiana Archaeology, Volume 28, pp. 1-14.
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In many numerical models and observational syntheses, the Southern Ocean upwelling represents the primary means by which deep dense water is brought to the surface. Shallower, wind-driven upwelling is also found off the west coasts of North and South America, northwest and southwest Africa, and southwest and southeast Australia, all associated with oceanic subtropical high pressure circulations. Some models of the ocean circulation suggest that broad-scale upwelling occurs in the tropics, as pressure driven flows converge water toward the low latitudes where it is diffusively warmed from above. The required diffusion coefficients, however, appear to be larger than are observed in the real ocean.
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In general, pre-Triassic stratigraphy and rifting has been confirmed below the northern North Sea but is poorly known and little conclusive information exists about Devonian and Carboniferous extensional events. While precise dating and the spatial extent of the active stretching are uncertain, recent stratigraphic syntheses suggest syn-rift dates of no younger than Scythian, with a possible initiation during the late or even early Permian. The following middle Triassic to early Jurassic post- rift stage is considerable better known. Subsidence (approximately nine intervals) in the northern North Sea was accompanied by faulting, stepping down from both margins towards the present Viking Graben axis.
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Early and seemingly inefficient syntheses of synephrine were discussed by Priestley and Moness, writing in 1940. These chemists optimized a route beginning with the O-benzoylation of p-hydroxy- phenacyl chloride, followed by reaction of the resulting O-protected chloride with N-methyl-benzylamine to give an amino-ketone. This intermediate was then hydrolyzed with HCl/alcohol to the p-hydroxy-aminoketone, and the product then reduced catalytically to give (racemic) synephrine. A later synthesis, due to Bergmann and Sulzbacher, began with the O-benzylation of p-hydroxy- benzaldehyde, followed by a Reformatskii reaction of the protected aldehyde with ethyl bromoacetate/Zn to give the expected β-hydroxy ester.
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Because of the configuration of their glycosidic bonds, galacto-oligosaccharides (GOS) largely resist hydrolysis by salivary and intestinal digestive enzymes. Galacto-oligosaccharides are classified as prebiotics, defined as non- digestible food ingredients that beneficially affect the host by stimulating the growth and/or activity of beneficial bacteria in the colon. The increased activity of these health-promoting bacteria results in a number of effects, both directly by the bacteria themselves or indirectly by the organic acids they produce via fermentation. Examples of effects are stimulation of immune functions, absorption of essential nutrients, production of the powerful anti- oxidant H2 gas and syntheses of certain vitamins.
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In 1858 Peter Griess passed ‘nitrous fumes’ (N2O3) into a solution of 2-amino-4,6-dinitrophenol (picramic acid) and isolated a product belonging to a new class of compounds: Azo dyes. Later, a new class of azo dyes that were based on “coupling” reactions entered the market. The new azo dyes were easy to make and assumed a vast variety of incredibly intense colors based on the chosen precursors. The chemists Z. Roussin, H. Caro, O. Witt, and P. Griess all put azo dyes on the market, and attempted to keep the syntheses as industrial secrets, Hoffman, however, determined the structure of their dyes and published his findings.
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Select chiral Lewis base catalysts developed by Scott Denmark for asymmetric catalysis An additional area of research for the Denmark group is the observation and characterization of the pre-transmetalation species of the boron-palladium adduct in Suzuki reactions using rapid-injection NMR techniques. Denmark also has research interests in computational chemistry and chemoinformatics, organizinc chemistry, and catalysis with nanoparticles. Denmark has published over 300 peer-reviewed articles and 27 book chapters and edited several book volumes including: Topics in Stereochemistry, Organic Reactions, and Lewis Base Catalysis in Organic Synthesis. He has been an editor of Organic Syntheses since 1994 and the editor-in-chief and president since 2008.
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In 1869 Schröder, Prinzhorn and Kraut repeated both Gerhardt's (from sodium salicylate) and von Gilm's (from salicylic acid) syntheses and concluded that both reactions gave the same compound—acetylsalicylic acid. (Prinzhorn is credited in the paper with conducting the experiments.) They were first to assign to it the correct structure with the acetyl group connected to the phenolic oxygen. It is likely that Hoffmann did as most chemists have always done, starting by studying the literature and recreating the published methods. On 10 August 1897 (according to his laboratory notebooks), Hoffmann found a better method for making ASA, from salicylic acid refluxed with acetic anhydride.
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In 1979, Archie Cochrane wrote 'It is surely a great criticism of our profession that we have not organised a critical summary, by specialty or subspecialty, adapted periodically, of all relevant randomised controlled trials'. Critical appraisal and synthesis of research findings in a systematic way emerged in the 1970s after Gene V. Glass introduced the term 'meta analysis' in 1976. According to Glass, meta-analysis is "the statistical analysis of a large collection of analysis results from individual studies for the purpose of integrating the findings". Early syntheses were conducted in broad areas of public policy and social interventions, with systematic research synthesis applied to medicine and health.
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He has brought synthesis and design to the field of biopolymers and the methodology of nucleic acids to the field of molecular recognition. His pioneering research at the interface of chemistry and biology has contributed greatly to a set of general chemical principles for sequence specific recognition at single sites in the human genome." # M. Frederick Hawthorne 1994 "For outstanding contributions to the fields of inorganic chemistry and organometallic chemistry through his seminal discoveries n the rapidly expanding area of borane clusters. Inparticular, his work has provided pioneering insights into the syntheses, structures, bonding, and reactivity patterns of polyhedral borane anions, carboranes, and metallocarboranes.
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Copper(II) acetate has found some use as an oxidizing agent in organic syntheses. In the Eglinton reaction Cu2(OAc)4 is used to couple terminal alkynes to give a 1,3-diyne: :Cu2(OAc)4 \+ 2 RC≡CH → 2 CuOAc + RC≡C−C≡CR + 2 HOAc The reaction proceeds via the intermediacy of copper(I) acetylides, which are then oxidized by the copper(II) acetate, releasing the acetylide radical. A related reaction involving copper acetylides is the synthesis of ynamines, terminal alkynes with amine groups using Cu2(OAc)4.. It has been used for hydroamination of acrylonitrile. It is also an oxidising agent in Barfoed's test.
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The preparation of pyrithione was first reported in 1950 by Shaw and was prepared by reaction of 2-chloropyridine N-oxide with sodium hydrogensulfide followed by acidification, or more recently with sodium sulfide. 2-chloropyridine N-oxide itself can be prepared from 2-chloropyridine using peracetic acid. Another approach involves treating the same starting N-oxide with thiourea to afford pyridyl-2-isothiouronium chloride N-oxide which undergoes base hydrolysis to pyrithione. 2-Bromopyridine can be oxidised to its N-oxide using a suitable peracid (as per 2-chloropyridine), both approaches being analogous to that reported in Organic Syntheses for the oxidation of pyridine to its N-oxide.
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The cluster has D3h symmetry, consisting of an equilateral triangle of Os atoms, each of which bears two axial and two equatorial CO ligands. The Os–Os bond distance is 2.88 Â (288 pm).Corey, E. R.; Dahl, L. F. “The Molecular and Crystal Structure of Os3(CO)12” Inorganic Chemistry 1962, volume 1, pages 521–526; . Ru3(CO)12 has the same structure, whereas Fe3(CO)12 is different, with two bridging CO ligands resulting in C2v symmetry. Os3(CO)12 is prepared by the direct reaction of OsO4 with carbon monoxide at 175 °C:Drake, S. R.; Loveday, P. A. “Dodecarbonyltriosmium” Inorganic Syntheses, 1990, volume 28, pages 230–231. .
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The aza-Cope/Mannich reaction is often the most efficient way to synthesize pyrrolidine rings, and thus has a number of applications in natural product total syntheses. Because of its diastereoselectivity this reaction has added to the catalog of asymmetric synthesis tools, as seen in the many examples of asymmetric alkaloids synthesized using the reaction. As we have seen in the first aza-Cope/Mannich reaction and in the elucidation of the reaction's stereochemistry, the aza-Cope/Mannich reaction can be used to form pyrrolidine rings and pyrrolizidine rings. It can be used to create many additional ring structures useful in synthesis, such as indolizidine cycles and indole rings.
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The intellectual foundations of Neotoma trace back to efforts by early paleontologists and paleoecologists in the first half of the 20th century to assemble many individual records into larger mapped syntheses. As von Post wrote, paleoecologists must “think horizontally, work vertically,” i.e. think across both time and space to understand the processes governing the ever-changing distribution of species, the associations among species, and the diversity of life. These efforts accelerated in the 1970s and 1980s, when a number of scientific teams began assembling databases of fossil distributions to study the spatial distributions of species over space and time and the effects of past environmental variations on these distributions.
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He is largely remembered for his work involving mineralogical syntheses, being credited with laboratory reproduction of quartz, tridymite, zircon, beryl, mica, alumina and many other minerals.Corpus Etampois biography (in French) He determined the temperatures at which minerals dissociate as well as the temperature at which they will crystallize into a particular crystal system. He also conducted research on the oxides of nitrogen.Torchbearers of Chemistry: Portraits and Brief Biographies of Scientists by Henry Monmouth Smith His scientific papers were published in the Académie des sciences (CRAS), the Bulletin de la Société chimique, the Annales de chimie et de physique, the Annales Scientifiques de l'École Normale Supérieure and the Revue scientifique.
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Vollständiges Textbuch von Goethes "Der Zauberflöte zweyter Theil – Fragment" mit einer Einleitung und Neuinterpretation von George Cebadal. Norderstedt 2016, pp. 50-51. Furthermore, Goethe's Magic Flute II shows numerous motifs of syntheses (like Papagena and Papageno have to use working and activity as well as enjoyment and calm to get children),Cebadal, George, ed.: Goethes: Die Zauberflöte II. Die Entdeckung von Goethes ägyptischen Mysterien im Bindeglied zwischen Mozarts "Zauberflöte" und der "Faust"-Dichtung. Vollständiges Textbuch von Goethes "Der Zauberflöte zweyter Theil – Fragment" mit einer Einleitung und Neuinterpretation von George Cebadal. Norderstedt 2016, p. 61. that seems to suggest a use of both systems, instead of becoming absolutely obsessed by one.
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Ferric nitrate is the catalyst of choice for the synthesis of sodium amide from a solution of sodium in ammonia: As of 2007, 22 other entries describe similar preparations in Organic Syntheses : 2 NH3 \+ 2 Na -> 2 NaNH2 \+ H2 Certain clays impregnated with ferric nitrate have been shown to be useful oxidants in organic synthesis. For example, ferric nitrate on Montmorillonite—a reagent called "Clayfen"—has been employed for the oxidation of alcohols to aldehydes and thiols to disulfides.Cornélis, A. Laszlo, P.; Zettler, M. W. "Iron(III) Nitrate–K10 Montmorillonite Clay" in Encyclopedia of Reagents for Organic Synthesis (Ed: L. Paquette) 2004, J. Wiley & Sons, New York. .
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The beauty of this method is that the identity of each product can be known simply by its location along the thread, and the corresponding biological activity is identified by Fourier transformation of fluorescence signals. Use of a traceless linker In most of the syntheses described here, it is necessary to attach and remove the starting reagent to/from a solid support. This can lead to the generation of a hydroxyl group, which can potentially affect the biological activity of a target compound. Ellman uses solid phase supports in a multi-step synthesis scheme to obtain 192 individual 1,4-benzodiazepine derivatives, which are well-known therapeutic agents.
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Vernier templating refers to the syntheses of complexes using templates and molecular building blocks with mismatching co-ordination numbers to construct larger molecular systems by incorporating more than one template molecule and more molecular building blocks than usual. Porphyrin nanoring systems are excellent examples in realising this methodology and giant artificial molecular systems with their molecular weights of small proteins can be constructed. Based on the work of organic synthesis, his research interests have found wide range of collaborators from versatile academic backgrounds all over the world. It was found that elongated/encapsulated pi-conjugate systems constructed by porphyrins showed unprecedented physical properties in charge transfer, two-photon absorption, etc.
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Myers and co-workers have pioneered the application of transannular anionic cyclization reactions in the synthesis of the 5,9-fused bicyclic core of kedarcidin chromophore and neocarzinostatin chromophore. In the first incarnation, hydride delivery to a cyclic tetrayne was guided by aluminum coordination to a proximal alkoxide, thus generating the desired enediyne core in one step via two successive 5-exo-dig–type cyclizations. Later-generation syntheses of the core intercept this cascade cyclization, relying on lithium-halogen exchange on a cyclic vinyl bromide to generate the vinyl anion precursor to the bicyclic product. Transannular cyclization in the synthesis of the bicyclic core of kedarcidin chromophore.
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Once the corrin structure was formed by either approach, the three C-H-chirogenic centers at the periphery adjacent to the chromophore system turned out to be prone to epimerizations with exceptional ease. This required a separation of diastereomers after most of the chemical steps in this advanced stage of the syntheses. It was fortunate indeed that, just around that time, the technique of high pressure liquid chromatography (HPLC) had been developed in analytical chemistry. HPLC became an indispensable tool in both laboratories; its use in the B12 project, pioneered by Jakob Schreiber at ETH, was the earliest application of the technique in natural product synthesis.
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Ru(CO)5 was originally prepared by carbonylation of ruthenium salts in the presence of a reducing agent.W. Manchot, Wilhelm J. Manchot "Darstellung von Rutheniumcarbonylen und -nitrosylen" Zeitschrift für Anorganische und Allgemeine Chemie 1936, volume 226, pp. 385-415. A more recent preparation involves photolysis of triruthenium dodecacarbonyl in the presence of carbon monoxide:Adams, R. D.; Barnard, T. S.; Cortopassi, J. E.; Wu, W.; Li, Z. "Platinum-ruthenium carbonyl cluster complexes" Inorganic Syntheses 1998, volume 32, pp. 280-284. :Ru3(CO)12 \+ 3 CO 3 Ru(CO)5 It is characterized by two intense νCO bands in the IR spectrum at 2038 and 2003 cm−1 (hexane solution).
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Iodolactonization has been used in the synthesis of many biologically important products such as the tumor growth inhibitors vernolepin and vernomenin, the pancreatic lipase inhibitor vibralactone, and prostaglandins, a lipid found in animals. The following total syntheses all use iodolactonization as a key step in obtaining the desired product. In 1977, Samuel Danishefsky and coworkers were able to synthesize the tumor growth inhibitors dl-vernolepin and dl-vernomenin via a multistep process in which a lactonization was employed. This synthesis demonstrates the use of iodolactonization to preferentially form a five- membered ring over a four- or six-membered ring, as expected from Baldwin's Rules.
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Amolak Chand Jain (born 1928) is an Indian natural product chemist, academic and the head of the department of chemistry at Delhi University, University of Jammu and Himachal Pradesh University. He is known for his studies on polyphenols, flavonoids and isoflavonoids and their syntheses. He is an elected fellow of the Indian National Science Academy and the National Academy of Sciences, India and a life member of the International Academy of Physical Sciences. The Council of Scientific and Industrial Research, the apex agency of the Government of India for scientific research, awarded him the Shanti Swarup Bhatnagar Prize for Science and Technology, one of the highest Indian science awards, in 1969, for his contributions to chemical sciences.
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His experiments were among the first to show that biodiversity enhances the efficiency and productivity of ecosystems through niche partitioning among species, and via facilitative interactions that cause diverse communities to be greater than the sum-of-their-parts. These mechanisms had long-been presumed to operate in nature, but empirical evidence was lacking. Cardinale is perhaps best known for his leadership in organizing major data syntheses that have helped foster a consensus about the probable consequences of biodiversity loss for humanity. He has organized numerous working groups funded by the U.S. National Science Foundation, the United Nations Environmental Program, the National Center for Ecological Analysis and Synthesis, and the Socio-Economic Environmental Synthesis Center.
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Since the cylindrocyclophanes have such a unique structure and exciting biological possibilities due to their cytotoxicity, there have been numerous efforts to create them synthetically in the laboratory. One of the first attempts was the total synthesis of cylindrocyclophane F, which was accomplished in 20 steps with an 8.3% yield. This, along with other syntheses of cylindrocyclophanes, relies on multistep reaction mechanisms, typically employing Myers reductive coupling and Kowalski ester homologation to obtain the beginning resorcinol fragments and Danheiser benzannulation to construct the aromatic rings with multiple functional groups. After the first total synthesis of cylindrocyclophane F, total synthesis of cylindrocyclophanes A and F were accomplished using a new olefin metathesis dimerization cascade.
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For his thesis, he chose to produce an axiomatization of Cantor's set theory. He graduated as a chemical engineer from ETH Zurich in 1926 (although Wigner says that von Neumann was never very attached to the subject of chemistry),The Collected Works of Eugene Paul Wigner: Historical, Philosophical, and Socio-Political Papers. Historical and Biographical Reflections and Syntheses, By Eugene Paul Wigner, (Springer 2013), page 128 and passed his final examinations for his Ph.D. in mathematics simultaneously with his chemical engineering degree, of which Wigner wrote, "Evidently a Ph.D. thesis and examination did not constitute an appreciable effort." He then went to the University of Göttingen on a grant from the Rockefeller Foundation to study mathematics under David Hilbert.
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Einstein stressed the importance of Broglie's work both explicitly and by building further on it. In 1925, Austrian-born physicist Wolfgang Pauli developed the Pauli exclusion principle, which states that no two electrons around a single nucleus in an atom can occupy the same quantum state simultaneously, as described by four quantum numbers. Pauli made major contributions to quantum mechanics and quantum field theory - he was awarded the 1945 Nobel Prize for Physics for his discovery of the Pauli exclusion principle - as well as solid-state physics, and he successfully hypothesized the existence of the neutrino. In addition to his original work, he wrote masterful syntheses of several areas of physical theory that are considered classics of scientific literature.
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Stoddart is one of only a few chemists of the past quarter century to pioneer a new field in organic chemistry. By establishing a new field where the main feature is mechanical bonds he has paved the way for molecular recognition, self-assembly processes for template-directed mechanically interlocked syntheses, molecular switches, and motor-molecules. These advances have formed the basis of the fields of nanoelectronic devices, nanoelectromechanical systems, and molecular machines. One of his major contributions to the development of mechanically-interlocked molecular architectures such as rotaxanes and catenanes has been the establishment of efficient synthetic protocols based on the binding of cyclobis(paraquat-p- phenylene) with electron-rich aromatic guests.
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Homologation reactions like the Kowalski ester homologation provide simple examples of insertion process in organic synthesis. In the Arndt-Eistert reaction, a methylene unit is inserted into the carboxyl-carbon bond of carboxylic acid to form the next acid in the homologous series. Organic Syntheses provides the example of t-BOC protected (S)-phenylalanine (2-amino-3-phenylpropanoic acid) being reacted sequentially with triethylamine, ethyl chloroformate, and diazomethane to produce the α-diazoketone, which is then reacted with silver trifluoroacetate / triethylamine in aqueous solution to generate the t-BOC protected form of (S)-3-amino-4-phenylbutanoic acid. :Homologation of N-boc-phenylalanine Mechanistically, the α-diazoketone undergoes a Wolff rearrangement to form a ketene in a 1,2-rearrangement.
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His work on medium-sized alicyclic and heterocyclic rings established him as a pioneer in stereochemistry and conformational theory and brought an invitation to give the first Centenary Lecture of the Chemical Society in London in 1949. He synthesised medium-sized ring compounds with 8 to 12 members from dicarboxylic acid esters by acyloin condensation and explained their unusual chemical reactivity by a "nonclassical" strain because of energetically unfavorable conformations. He also contributed to the understanding of Bredt's rule by showing that a double bond may occur at the bridgehead if the ring is large enough. In his research of asymmetric syntheses, Prelog studied enantioselective reactions and established rules for the relationship between configuration of educts and products.
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Watt, Montgomery (1948) Free-Will and Predestination in Early Islam. London: Luzac & Co. The problem of free will, in this context, is the problem of how our actions can be free if there is a being who has determined them for us in advance, or if they are already set in time. Other forms of determinism are more relevant to compatibilism, such as biological determinism, the idea that all behaviors, beliefs, and desires are fixed by our genetic endowment and our biochemical makeup, the latter of which is affected by both genes and environment, cultural determinism and psychological determinism. Combinations and syntheses of determinist theses, such as bio-environmental determinism, are even more common.
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The complex is prepared by reducing chloroauric acid with triphenylphosphine in 95% ethanol:Pierre Braunstein, Hans Lehner, Dominique Matt "A Platinum-Gold Cluster: Chloro-1κCl-Bis(Triethylphosphine-1κP)Bis(Triphenylphosphine)-2κP, 3κP-Triangulo- Digold-Platinum(1 +) Trifluoromethanesulfonate" Inorganic Syntheses, 1990, Volume 27, Pages 218–221. :HAuCl4 \+ H2O + 2 PPh3 → (Ph3P)AuCl + Ph3PO + 3 HCl Ph3PAuCl can also be prepared by treating a thioether complex of gold like (dimethyl sulfide)gold(I) chloride, [(Me2S)AuCl], with triphenylphosphine. The complex adopts a linear coordination geometry, which is typical of most gold(I) compounds. It crystallizes in the orthorhombic space group P212121 with a = 12.300(4) Å, b = 13.084(4) Å, c = 10.170(3) Å with Z = 4 formula units per unit cell.
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The Huang modification is a one-pot shortcut for the Wolff-Kishner reduction, a reaction in which ketone and aldehyde carbonyls are converted to the corresponding methylene or methyl groups via the hydrazone derivative. The Huang-Minlon procedure calls for first heating the carbonyl compound, sodium or potassium hydroxide, and hydrazine hydrate (85% hydrazine) together in ethylene glycol for 1 to 2 h to form the hydrazone before removing the reflux condenser and allowing the water and excess hydrazine to boil off, after which the temperature rises to around 195 °C, and the reaction mixture is heated for another 3 to 4 h to decompose the hydrazone.Organic Syntheses, Coll. Vol. 4, p.
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One-pot preparation of 7-Hydroxyquinoline In chemistry a one-pot synthesis is a strategy to improve the efficiency of a chemical reaction whereby a reactant is subjected to successive chemical reactions in just one reactor. This is much desired by chemists because avoiding a lengthy separation process and purification of the intermediate chemical compounds can save time and resources while increasing chemical yield. An example of a one-pot synthesis is the total synthesis of tropinone or the Gassman indole synthesis. Sequential one-pot syntheses can be used to generate even complex targets with multiple stereocentres, such as oseltamivir, which may significantly shorten the number of steps required overall and have important commercial implications.
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Selenium hexasulfide is a chemical compound with formula Se2S6. Its molecular structure consists of a ring of two selenium and six sulfur atoms, analogous to the S8 allotrope of sulfur (cyclooctasulfur) and other selenium sulfides with formula SenS8−n. There are several isomers depending on the relative placement of the selenium atoms in the ring: 1,2 (with the two Se atoms adjacent), 1,3, 1,4, and 1,5 (with the Se atoms opposite).Arto Maaninen, Tristram Chivers, Masood Parvez, Jarkko Pietikäinen, and Risto S. Laitinen (1999), "Syntheses of THF Solutions of SeX2 (X = Cl, Br) and a New Route to Selenium Sulfides SenS8−n (n = 1−5): X-ray Crystal Structures of SeCl2(tht)2 and SeCl2·tmtu".
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1958, "618", 251–266.() Large scale operations for the fine chemical industry produce almost 150,000 tonnes of Koch acids and their derivatives annuallyWeissermel, K., Jargen-Arpe, H. In "Syntheses involving carbon monoxide", Industrial Organic Chemistry; VCH Publishers: New York, NY; pp. 141–145. () but also generate a great deal of waste, motivating ongoing attempts to use metal, solid acid, and other novel catalysts to enable the use of milder reaction conditions. Formic acid, which readily decomposes to carbon monoxide in the presence of acids or relatively low heat, is often used instead of carbon monoxide directly; this procedure was developed shortly after the Koch reaction and is more commonly referred to as the Koch–Haaf reaction.
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Yeast fatty acyl synthase, of Type I FAS, is composed of a α6β6 complex in which an αβ unit forms one functional center for fatty acid synthesis. Yeast fatty acyl synthase therefore has six reaction units for its fatty acid synthesis, in which each of these units function independently from one another. Each α and β subunit, in turn, has four functional domains, and together, the eight functional domains catalyze all the reactions of fatty acid synthesis in yeast, which includes: activation, priming, elongation, and termination. Consequently, yeast FAS is incredibly unique due to its structural complexity, which contains 48 functional centers for one α6β6 complex and can efficiently performs 6 fatty acid syntheses separately at one time.
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A somewhat more concise and cost-effective route better suited to large-scale production was patented by Upjohn in 1998. Retrieved on 13 June 2009. Later syntheses have included an "atom-economical" method starting from D-mannitol, developed by Indian pharmaceutical company Dr. Reddy's and reported in 1999, and a route starting from (S)-glyceraldehyde acetonide (prepared from vitamin C), developed by a team of researchers from Hunan Normal University in Changsha, Hunan, China. On 25 June 2008, during the 12th Annual Green Chemistry and Engineering Conference in New York, Pfizer reported the development of their "second-generation" synthesis of linezolid: a convergent, green synthesis starting from (S)-epichlorohydrin, with higher yield and a 56% reduction in total waste.
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The first total synthesis was accomplished in 2000 by the Danishefsky group at Columbia University, with a number of other syntheses following shortly thereafter by Williams, Ganesan, Fuji, Carreira, Horne, Overman, and most recently Trost. From a synthetic point of view, the most challenging structural features of the molecule are the C3 spirocyclic ring juncture and the adjacent prenyl-substituted carbon. Approaches toward preparing the skeleton of spirotryprostatin B have varied considerably. Danishefsky spirotryprostatin B synthesis :Danishfesky spirotryprostatin B synthesis In the Danishefsky synthesis, an amine derived from tryptophan was condensed with an aldehyde, triggering a Mannich-type reaction wherein the pendant oxindole acted as a nucleophile toward the intermediate iminium species.
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Ohloff returned to Industry in 1962, joining Firmenich in Geneva to head the process-research group. He was named the firm's research director and member of the board of directors in 1968, which he remained until his retirement in 1989. Ohloff's scientific work, which is documented in 228 publications and 111 patents,Wolfgang Giersch, Rerald Uhde, Ferdinand Näf: Günther Ohloff – Chemist & Pioneer in the Art of Perfumery, Chimia 58 (2004) 65−66 centered around ths structure elucidation and reactivity of terpenes, the industrial syntheses of odorants, and structure–odor correlations. He was the leading expert of empirical odor rules that predict the olfactory properties of new compounds, such as the "triaxial rule of ambergris sensation".
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PCA Chemical Space for Ethanol Descriptor Chemical Space for THF: ALOGP vs. MW The Open Notebook Science Challenge is a crowdsourcing research project which collects measurements of the non-aqueous solubility of organic compounds and publishes these as open data; findings are reported in an open notebook science manner. Although anyone may contribute research data, the competition is only open to post-secondary students in the USA and UK. The challenge in turn forms part of the UsefulChem project, an ongoing open notebook science effort to synthesize and screen potential new anti-malarial drugs.UsefulChem Data from the Solubility Challenge will be used to build predictive computational models of solubility for use in optimising syntheses.
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He was Chairman of the Merck Fellowship Board of the National Academy of Sciences in 1957. Clarke was much in demand for his talents as a lucid writer and was called on to serve as editor or referee throughout his career. He sat on the editorial board of Organic Syntheses (1921–32), and on the editorial board of the Journal of Biological Chemistry (1937–51), and was associate editor of the Journal of the American Chemical Society (1928–38)American Philosophical Society website, Hans Thacher Clarke Papers, accessed 27 June 2012 Clarke was an expert clarinet player, and received numerous requests to perform. His donated papers include one notebook dedicated to clarinet performance.
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According to his concepts, "the audiovisual art constitutes a specific means of social communication and expression, since it has intrinsic characteristics and qualities which determine an own language essence, which differentiates it and separates it from the cinema and television, turning it into an experience that aims at a different path, still not explored enough, in the field of communication, with completely new development possibilities in that field. This mainly happens in the audiovisual artistic conception, in which original syntheses and unexpected combinations may take place, which distinguish the audiovisual art as a particular art. Therefore, the audiovisual theme as an art resides in a main interest spot" (Audiovisualogía. El audiovisual como arte y medio de comunicación).
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In the Abhidhamma Pitaka's Dhammasangani, the first chapter identifies 56 states of material-world consciousness that are wholesome, including "lightness of sense and thought," upon which the text elaborates: :What on that occasion is repose of sense (kayāpassaddhi)? :The serenity, the composure which there is on that occasion, the calming, the tranquillizing, the tranquillity of the skandhas of feeling, perception and syntheses -- this is the serenity of sense that there then is. :What on that occasion is serenity of thought (cittapassaddhi)? :The serenity, the composure which there is on that occasion, the calming, the tranquillizing, the tranquillity of the skandha of intellect -- this is the serenity of thought that there then is.
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Extensive studies of diborane have led to the development of multiple syntheses. Most preparations entail reactions of hydride donors with boron halides or alkoxides. The industrial synthesis of diborane involves the reduction of BF3 by sodium hydride, lithium hydride or lithium aluminium hydride: :8 BF3 \+ 6 LiH → B2H6 \+ 6 LiBF4 Two laboratory methods start from boron trichloride with lithium aluminium hydride or from boron trifluoride ether solution with sodium borohydride. Both methods result in as much as 30% yield: :4 BCl3 \+ 3 LiAlH4 → 2 B2H6 \+ 3 LiAlCl4 :4 BF3 \+ 3 NaBH4 → 2 B2H6 \+ 3 NaBF4 Older methods entail the direct reaction of borohydride salts with a non-oxidizing acid, such as phosphoric acid or dilute sulfuric acid.
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Reisman began her independent career as an Assistant Professor at Caltech in 2008 and was promoted to Full Professor in 2014. The Reisman lab focuses on the synthesis of complex natural products and development of new chemical reactions, and the interplay between those two fields. The group completed the first enantioselective total syntheses of (–)-acetylaranotin (40 years after its isolation), (–)-Maoecrystal Z, (–)-8-Demethoxyrunanine, and (–)-Cepharatines A, C and D. Their total synthesis of (+)-ryanodol was completed in 15 synthetic steps, a significant improvement on the previous shortest synthetic route of 35 steps developed by Masayuki Inoue of the University of Tokyo. In 2019, Reisman and coworkers published the first total synthesis of isoryanoid diterpene (+)-perseanol in Nature.
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The main buildings of these cities are characterized by the lack of monumentality and the fact that the building materials are not well-hewn stones, which are especially observed in the buildings of Medieval Period. At the same time, the involvement of architects who are not well-known in the building process of cities had a major advantage: they were somewhat acquainted with local building materials and had certain information about how to apply them in construction. They combined the traditions of the old schools of architecture with the works of folk architects in the architecture of new cities. The most interesting syntheses of this period are observed in the architecture of Shaki and Karabakh khanates.
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The nature of NaCp depends strongly on its medium and for the purposes of planning syntheses, the reagent is often represented as a salt . Crystalline solvent-free NaCp, which is rarely encountered, is a "polydecker" sandwich complex, consisting of an infinite chain of alternating Na+ centers sandwiched between μ-η5:η5-C5H5 ligands. As a solution in donor solvents, NaCp is highly solvated, especially at the alkali metal as suggested by the isolability of the adduct Na(tmeda)Cp. In contrast to alkali metal cyclopentadienides, tetrabutylammonium cyclopentadienide (Bu4N+C5H5−) was found to be supported entirely by ionic bonding and its structure is representative of the structure of the cyclopentadienide anion (C5H5−, Cp−) in the solid state.
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Anhydrous chromium(III) chloride may be prepared by chlorination of chromium metal directly, or indirectly by carbothermic chlorination of chromium(III) oxide at 650–800 °CD. Nicholls, Complexes and First-Row Transition Elements, Macmillan Press, London, 1973. :Cr2O3 \+ 3 C + 3 Cl2 → 2 CrCl3 \+ 3 CO Dehydration with trimethylsilyl chloride in THF gives the solvate: :CrCl3 \+ 12 Me3SiCl → CrCl3(THF)3 \+ 6 (Me3Si)2O + 12 HCl It may also be prepared by treating the hexahydrate with thionyl chloride:Pray, A. P. "Anhydrous Metal Chlorides" Inorganic Syntheses, 1990, vol 28, 321–2. :CrCl3 \+ 6 SOCl2 → CrCl3 \+ 6 SO2 \+ 12 HCl The hydrated chlorides are prepared by treatment of chromate with hydrochloric acid and methanol.
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In these working groups, Cardinale and his colleagues have assembled extensive datasets of thousands of experiments and observational studies that have quantified how changes in biodiversity impact a wide variety of ecological processes and ecosystem services for organisms inhabiting 30 biomes on 5 continents. Their syntheses have led to publication of 15 formal meta- analyses. In 2012, Cardinale organized and led an invited review for a special issue of Nature dedicated to the 20th anniversary of the Rio Earth Summit in which his colleagues and he synthesized over 1,700 papers that have examined biodiversity's impact on 34 ecosystem goods and services. This synthesis revealed a remarkable level of generality in how biodiversity impacts the functioning of Earth's ecosystems and the services they provide to society.
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This synthesis differentiates itself in that it takes an "assembly line" synthesis approach, as opposed to the conventional iterative synthetic approach taken in previous syntheses which normally necessitate functional-group interconversions and repetitive purifications for aliphatic chain extensions, such as the one found in kalkitoxin. This novel approach is achieved through the use of reagent-controlled chain extension of a boronic ester, which relies on a spontaneous 1,2-migration after formation of an intermediate compound incorporating a newly added lithiated benzoate ester building block. This allows for control of chirality at each addition by selecting the chirality of each benzoate ester added. Furthermore, this avoids repetitive interconversion and purification steps normally required for repeat chain extensions, which increases yield and efficiency and decreases labor.
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Acetylacetone is prepared industrially by the thermal rearrangement of isopropenyl acetate. :CH2(CH3)COC(O)Me → MeC(O)CH2C(O)Me Laboratory routes to acetylacetone begin also with acetone. Acetone and acetic anhydride upon the addition of boron trifluoride (BF3) catalyst: :(CH3CO)2O + CH3C(O)CH3 → CH3C(O)CH2C(O)CH3 A second synthesis involves the base-catalyzed condensation of acetone and ethyl acetate, followed by acidification: :NaOEt + EtO2CCH3 \+ CH3C(O)CH3 → NaCH3C(O)CHC(O)CH3 \+ 2 EtOH :NaCH3C(O)CHC(O)CH3 \+ HCl → CH3C(O)CH2C(O)CH3 \+ NaCl Because of the ease of these syntheses, many analogues of acetylacetonates are known. Some examples include C6H5C(O)CH2C(O)C6H5 (dbaH) and (CH3)3CC(O)CH2C(O)CC(CH3)3.
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A more modern synthesis utilizes copper chloride in a room temperature reaction with sodium citrate or myristic acid in an aqueous solution containing sodium formaldehyde sulfoxylate to obtain a pure copper nanoparticle powder. While these syntheses generate fairly consistent copper nanoparticles, the possibility of controlling the sizes and shapes of copper nanoparticles has also been reported. The reduction of copper(II) acetylacetonate in organic solvent with oleyl amine and oleic acid causes the formation of rod and cube-shaped nanoparticles while variations in reaction temperature affect the size of the synthesized particles. Another method of synthesis involves using copper (II) hydrazine carboxylate salt with ultrasound or heat in water to generate a radical reaction, as shown in the figure to the right.
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At high temperatures, equilibrium thermodynamic models appear to be satisfactory for the description of kaolinite dissolution and nucleation, because the thermal energy suffices to overcome the energy barriers involved in the nucleation process. The importance of syntheses at ambient temperature and atmospheric pressure towards the understanding of the mechanism involved in the nucleation of clay minerals lies in overcoming these energy barriers. As indicated by Caillère and Hénin (1960) the processes involved will have to be studied in well- defined experiments, because it is virtually impossible to isolate the factors involved by mere deduction from complex natural physico-chemical systems such as the soil environment. Fripiat and Herbillon (1971), in a review on the formation of kaolinite, raised the fundamental question how a disordered material (i.e.
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Sodium chloride , commonly known as salt (although sea salt also contains other chemical salts), is an ionic compound with the chemical formula NaCl, representing a 1:1 ratio of sodium and chloride ions. With molar masses of 22.99 and 35.45 g/mol respectively, 100 g of NaCl contains 39.34 g Na and 60.66 g Cl. Sodium chloride is the salt most responsible for the salinity of seawater and of the extracellular fluid of many multicellular organisms. In its edible form of table salt, it is commonly used as a condiment and food preservative. Large quantities of sodium chloride are used in many industrial processes, and it is a major source of sodium and chlorine compounds used as feedstocks for further chemical syntheses.
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Waste left behind from a methamphetamine lab Short-term exposure to high concentrations of chemical vapors that exist in black-market methamphetamine laboratories can cause severe health problems and death. Exposure to these substances can occur from volatile air emissions, spills, fires, and explosions. Such methamphetamine labs are sometimes discovered when emergency personnel respond to fires due to improper handling of volatile or flammable materials. Single-pot "shake and bake" syntheses are particularly prone to explode and ignite, and, when abandoned, still pose a severe hazard to firefighters.. Ingredients involved in synthesizing methamphetamine products illicitly (and seldom amphetamine as well) may be carcinogens, flammable, prone to react violently and explode with great force, or corrosive, as well as the compounds used to synthesize the aforementioned ingredients.
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Józef Maria Hoene-Wroński Andrzej Towiański Józef Gołuchowski Adam Mickiewicz Juliusz Słowacki Józef Kremer Zygmunt Krasiński Karol Libelt Michał Wiszniewski Bronisław Trentowski August Cieszkowski In the early nineteenth century, following a generation imbued with Enlightenment ideas, Poland passed directly to a maximalist philosophical program, to absolute metaphysics, to syntheses, to great systems, to reform of the world through philosophy; and broke with Positivism, the doctrines of the Enlightenment, and the precepts of the Scottish School of Common Sense.Tatarkiewicz, Zarys..., p. 17. The Polish metaphysical blossoming occurred between the November 1830 and January 1863 Uprisings, and stemmed from the spiritual aspirations of a politically humiliated people. The Poles' metaphysic, although drawing on German idealism, differed considerably from it; it was Spiritualist rather than Idealist.
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In contrast Neo-Kabbalistic approaches welcome views of Revelation compatible with the critical perspectives of Modernist or Open Orthodoxy, Jewish feminism, and Non-Orthodox Judaisms. Among Kabbalists at the eve of modernity, the Vilna Gaon (18th century) foresaw the unfolding messianic Kabbalistic redemption of Sciences. In the early 20th century, Abraham Isaac Kook expressed a mystical process where the secular unconsciously deepens the sacred. The present generation has seen the proliferation of syntheses between Kabbalah and secular wisdoms, driven by Jewish outreach, traditional and Neo-Hasidic spirituality, publication of esoteric mystical works, deep involvement in both Jewish and secular cultures, revisionist ideas compatible with mysticism in secular wisdoms, and contemporary flourishing of new scholarship and perspectives by Jewish mystical academia.
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Zames’s research focused on imprecisely modelled systems using the input-output method, an approach that is distinct from the state space representation that dominated control theory for several decades. At the core of much of his work is the objective of complexity reduction through organization: > For the purposes of control design, gross qualitative properties such as > robustness can be analyzed and predicted without depending on accurate > models or syntheses. Mathematical analysis provides topological tools that > are very well suited for this purpose, such as compactness, contraction, and > fixed-point methods. Furthermore, in control design, where there is lots of > model uncertainty, it is often more important to be able to gauge > qualitative behaviour (robustness, stability, existence of oscillations) > than to compute exactly.
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V. A. Urechia (most common version of Vasile Alexandrescu Urechia, ; born Vasile Alexandrescu and also known as Urechiă, Urechea, Ureche, Popovici- Ureche or Vasile Urechea-Alexandrescu; February 15, 1834 - November 21, 1901) was a Moldavian, later Romanian historian, Romantic author of historical fiction and plays, academic and politician. The author of Romanian history syntheses, a noted bibliographer, heraldist, ethnographer and folklorist, he founded and managed a private school, later holding teaching positions at the University of Iaşi and University of Bucharest. Urechia was also one of the founding members of the Romanian Academy and, as frequent traveler to Spain and fluent speaker of Spanish, a corresponding member of the Royal Spanish Academy. He was the father of satirist Alceu Urechia.
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If conditions are acidic enough, the acetic acid can be further reacted via the Fischer esterification pathway, but at a much slower pace. However, in many carefully designed syntheses, reagents can be designed such that acid anhydrides are generated in situ and carboxylic acid byproducts are reactivated, and Fischer esterification routes are not necessarily mutually exclusive with acetic anhydride routes. (Examples of this include the common undergraduate organic lab experiment involving the acetylation of salicylic acid to yield aspirin.) Fischer esterification is primarily a thermodynamically-controlled process: because of its slowness, the most stable ester tends to be the major product. This can be a desirable trait if there are multiple reaction sites and side product esters to be avoided.
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By virtue of the lone electron pair on carbon, isocyanides serves as ligands in coordination chemistry, especially with metals in the 0, +1, and +2 oxidation states. tert-Butyl isocyanide has been shown to stabilize metals in unusual oxidation states, such as Pd(I).Rettig, M.F.; Maitlis, P.M.; Cotton, F.A.; Webb, T.R. Tetrakis(tert-butyl isocyanide)Di-μ-chloro-dipalladium(I). Inorganic Syntheses, 1990, 28, 110-113. . : Pd(dba)2 \+ PdCl2(C6H5CN)2 \+ 4 t-BuNC → [(t-BuNC)2PdCl]2 \+ 2 dba + 2 C6H5CN tert-Butyl isocyanide can form hepta-coordinate homoleptic complexes, despite having a large t-Bu group, which is held far away from the metal center because of the linearity of the M-C≡N-C linkages.
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Although untrue from a historical perspective (see the history of the steroid, cortisone), total synthesis in the modern age has largely been an academic endeavour (in terms of manpower applied to problems). However, industrial concerns may pick up particular avenues of total synthesis efforts and expend considerable resources on particular natural product targets, especially if semi-synthesis can be applied to complex, natural product-derived drugs. Even so, there is a continuing discussion regarding the value of total synthesis as an academic enterprise, some aspects of which are summarised here. Total synthesis projects often require a variety of reactions and so efforts to achieve complex total syntheses serve to prepare chemists for pursuits particularly in pharmaceutical discovery chemistry as well as in process chemistry.
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At the time of his death, he had published over 120 scientific papers, including two in 2009, in the fields of glacier monitoring, causes of sea-level rise, methods of mass balance and runoff study, and all aspects of glaciers in relation to climate change and meltwater production. Until his last hours, he was working on a major compendium that he was planning to publish in Moscow as an issue of "Materials of Glaciological Research." The best known of Mark’s contributions to the scientific literature are his several global compilations and syntheses of glacier mass balance. His results figured in the climate-change and sea-level sections of the Intergovernmental Panel on Climate Change reports, which received the Nobel Peace Prize in 2007.
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An early event in the modern synthesis was R. A. Fisher's 1918 paper on mathematical population genetics, but William Bateson, and separately Udny Yule, were already starting to show how Mendelian genetics could work in evolution in 1902. Different syntheses followed, accompanying the gradual breakup of the early 20th century synthesis, including with social behaviour in E. O. Wilson's sociobiology in 1975, evolutionary developmental biology's integration of embryology with genetics and evolution, starting in 1977, and Massimo Pigliucci's proposed extended evolutionary synthesis of 2007. In the view of the evolutionary biologist Eugene Koonin in 2009, the modern synthesis will be replaced by a 'post-modern' synthesis that will include revolutionary changes in molecular biology, the study of prokaryotes and the resulting tree of life, and genomics.
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In 1982, a historical note on a series of evolutionary biology books could state without qualification that evolution is the central organizing principle of biology. Smocovitis commented on this that "What the architects of the synthesis had worked to construct had by 1982 become a matter of fact", adding in a footnote that "the centrality of evolution had thus been rendered tacit knowledge, part of the received wisdom of the profession". By the late 20th century, however, the modern synthesis was showing its age, and fresh syntheses to remedy its defects and fill in its gaps were proposed from different directions. These have included such diverse fields as the study of society, developmental biology, epigenetics, molecular biology, microbiology, genomics, symbiogenesis, and horizontal gene transfer.
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Hexamethylbenzene has uses in various areas of chemical research. The oxidation of it to form 2,3,4,5,6,6-hexamethyl-2,4-cyclohexadienone (reportedly an intermediate in its formation from phenol) has been reported in Organic Syntheses using trifluoroperacetic acid or an acidic solution of hydrogen peroxide: center It has also been used as a solvent for 3He-NMR spectroscopy. Just as with benzene itself, the electron-rich aromatic system in hexamethylbenzene allows it to act as a ligand in organometallic chemistry. The electron-donating nature of the methyl groups—both that there are six of them individually and that there are six meta pairs among them—enhance the basicity of the central ring by six to seven orders of magnitude relative to benzene.
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In the early days of this party, the prevailing nationalism and populism in 1910s China played an important part in the ideology of early communists such as Li Dazhao and Mao Zedong. On the one hand, Marxism was a spiritual utopia to the early communists, while, on the other hand, they modified or "Sinicized" some doctrines of communist ideology in a realistic and nationalist way to support their revolution in China. These ideological syntheses led to the emergence of the famous Great Leap Forward movement and the Cultural Revolution. In recent years, it has been argued, mainly by foreign commentators, that the CCP does not have an ideology, and that the party organization is pragmatic and interested only in what works.
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The unusual electronics of the oxaziridine system may be exploited to perform a number of oxygen and nitrogen transfer reactions including, but not limited to: α-hydroxylation of enolates, epoxidation of alkenes, selective oxidation of sulfides and selenides, amination of N-nucleophiles and N-acylamidation. The peroxide process for the industrial production of hydrazine through the oxidation of ammonia with hydrogen peroxide in the presence of ketones was developed in the early 1970s.. .. Chiral camphorsulfonyloxaziridines proved useful in the syntheses of complex products, such as taxol which is marketed as a chemotherapy agent. Both the Holton Taxol total synthesis and the Wender Taxol total synthesis feature asymmetric α-hydroxylation with camphorsulfonyloxaziridine. :A display of selected reactions that demonstrates the wide breadth of oxaziridine reactivity.
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Previous prebiotic syntheses of nucleotides had attempted to form them through assembly of their constituent parts, a nucleobase, sugar, and phosphate, but with only limited efficacy for purine nucleotides, and no success for pyrimidine nucleotides. However, Sutherland produced a synthesis resulting in the formation of β-ribocytidine-2',3' cyclic phosphate, a partially activated nucleotide, that is remarkable for its stereospecifity and yield. Instead of assembling the nucleotide components in stepwise linear reactions, the synthesis proceeds through the reaction of cyanoacetylene with an aminooxazole intermediate that is formed from glycolaldehyde and cyanamide, molecules that were likely present on early Earth. In June 2012, Sutherland, along with his former colleague, the chemist Matthew Powner, from University College London, won the Origin of Life Challenge issued by Harry Lonsdale.
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David G. Anderson (born 1949) is an archaeologist in the department of anthropology at the University of Tennessee, Knoxville, who specializes in Southeastern archaeology. His professional interests include climate change and human response, exploring the development of cultural complexity in Eastern North America, maintaining and improving the nation's Cultural Resource management (CRM) program, teaching and writing about archaeology, and developing technical and popular syntheses of archaeological research. He is the project director of the on-line Paleoindian Database of the Americas (PIDBA). and a Co-Director, with Joshua J. Wells, Eric C, Kansa, and Sarah Whitcher Kansa, of the Digital Index of North American Archaeology (DINAA) The majority of Anderson's career has been involved in Cultural Resources Management (CRM) archaeology.
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Dr Rob studied science at the University of Queensland, graduating with a Bachelor of Science in 1994, and going on to a complete an honours year in 1995, writing a thesis on superconductors. In 1996, he went directly into his PhD in the field of Material Chemistry, which he graduated in 2000. His PhD thesis was entitled "Investigation and characterisation of co-precipitation syntheses for the production of La1-xSrxMnO3" in the field of "Solid oxide fuel cells using Perovskite and ceramic powders". After 12 months traveling and work in Europe, he returned to Australia and commenced work at the Commonwealth Scientific & Industrial Research Organisation (CSIRO) in the education children's division, where he visited schools & juvenile detention centres presenting scientific experiments & explanations for the audience.
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There are a number of important syntheses of pyrroles that are operated in the manner of the Knorr Synthesis, despite having mechanisms of very different connectivity between the starting materials and the pyrrolic product. Hans Fischer and Emmy Fink found that Zanetti's synthesis from 2,4-pentanedione and ethyl 2-oximinoacetoacetate gave ethyl 3,5-dimethylpyrrole-2-carboxylate as a trace byproduct. Similarly, 3-ketobutyraldehyde diethyl acetal led to the formation of ethyl 5-methylpyrrole-2-carboxylate. Both of these products resulted from the loss of the acetyl group from the inferred ethyl 2-aminoacetoacetate intermediate. An important product of the Fischer-Fink synthesis was ethyl 4,5-dimethylpyrrole-2-carboxylate, made from ethyl 2-oximinoacetoacetate and 2-methyl-3-oxobutanal, in turn made by the Claisen condensation of 2-butanone with ethyl formate.
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Another point of diversion between these two syntheses is the number of carbons separating the keto-auxiliary group from the chiral center at C7. This group was separated by one carbon from C7 in the first total synthesis, so the keto- auxiliary moiety could be converted to a carboxylic acid, in anticipation of addition of the amino alcohol immediately thereafter. In this synthesis, this keto-auxiliary group is directly adjacent to C7, necessitating a one carbon homologation, before construction of the thiazoline ring. This was achieved through reductive bond cleavage of the auxiliary group to a primary alcohol and oxidation to the corresponding aldehyde, Wittig reaction using an ylide carrying a methoxy group to produce an enol ether, hydrolysis to the aldehyde and finally oxidation to produce the carboxylic acid.
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The final synthetic chemistry stages involve the production of a lead compound in suitable quantity and quality to allow large scale animal testing, and then human clinical trials. This involves the optimization of the synthetic route for bulk industrial production, and discovery of the most suitable drug formulation. The former of these is still the bailiwick of medicinal chemistry, the latter brings in the specialization of formulation science (with its components of physical and polymer chemistry and materials science). The synthetic chemistry specialization in medicinal chemistry aimed at adaptation and optimization of the synthetic route for industrial scale syntheses of hundreds of kilograms or more is termed process synthesis, and involves thorough knowledge of acceptable synthetic practice in the context of large scale reactions (reaction thermodynamics, economics, safety, etc.).
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A strong driving force for the [4+2] cycloaddition of such species is a result of the establishment (or reestablishment) of aromaticity. Common methods for generating o-quinodimethanes include pyrolysis of benzocyclobutenes or the corresponding sulfone, 1,4-elimination of ortho benzylic silanes or stannanes, and reduction of α,α'-ortho benzylic dibromides. in situ generation of o-quinodomethanes On the contrary, stable dienes are rather unreactive and undergo Diels–Alder reactions only at elevated temperatures: for example, naphthalene can function as a diene, leading to adducts only with highly reactive dienophiles, such as N-phenyl- maleimide. Anthracene, being less aromatic (and therefore more reactive for Diels–Alder syntheses) in its central ring can form a 9,10 adduct with maleic anhydride at 80 °C and even with acetylene, a weak dienophile, at 250 °C.
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Upon completing his PhD, Brisdon worked for one year on a UKEA (Winfrith) funded project investigating on design, construction and testing of systems for sampling directly from a reaction chamber at or above atmospheric pressures and at high temperatures. He then completed his postdoctoral research at University of Leicester where he worked on synthesis of high oxidation-state transition metal fluorides and oxide-fluorides via high pressure and liquid fluorine syntheses and on the fluorination of the fullerene's, C60and C70. He then joined the University of Manchester as a Lecturer and was later on promoted to the position of Senior Lecturer. Brisdon's research in general is based on fluorine chemistry, including on HCFCs, fluorine-containing organometallic systems, fluorophosphines and fluorine-containing materials, such as ionic liquids and fluorographenes.
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Difficulties are encountered when trying to explain kaolinite formation under atmospheric conditions by extrapolation of thermodynamic data from the more successful high-temperature syntheses (as for example Meijer and Van der Plas, 1980 have pointed out). La Iglesia and Van Oosterwijk-Gastuche (1978) thought that the conditions under which kaolinite will nucleate can be deduced from stability diagrams, based as they are on dissolution data. Because of a lack of convincing results in their own experiments, La Iglesia and Van Oosterwijk-Gastuche (1978) had to conclude, however, that there were other, still unknown, factors involved in the low- temperature nucleation of kaolinite. Because of the observed very slow crystallization rates of kaolinite from solution at room temperature Fripiat and Herbillon (1971) postulated the existence of high activation energies in the low-temperature nucleation of kaolinite.
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In many numerical models and observational syntheses, the Southern Ocean upwelling represents the primary means by which deep dense water is brought to the surface. In some regions of Antarctica, wind-driven upwelling near the coast pulls relatively warm Circumpolar deep water onto the continental shelf, where it can enhance ice shelf melt and influence ice sheet stability. Shallower, wind-driven upwelling is also found in off the west coasts of North and South America, northwest and southwest Africa, and southwest and south Australia, all associated with oceanic subtropical high pressure circulations (see coastal upwelling above). Some models of the ocean circulation suggest that broad-scale upwelling occurs in the tropics, as pressure driven flows converge water toward the low latitudes where it is diffusively warmed from above.
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Modified aldol tandem reaction, decarboxylative aldol reaction as an example Palladium-mediated decarboxylative aldol reaction with allyl β-keto carboxylates Decarboxylative aldol reaction with malonic acid half thioester Modified aldol tandem reaction is a sequential chemical transformation that combines aldol reaction with other chemical reactions that generate enolates. Enolates are a common building block in chemical syntheses and are typically formed by the addition of base to a ketone or aldehyde. Modified Aldol tandem reactions allow similar reactivity to be produced without the need for a base which may have adverse effects in a given chemical synthesis. A representative example is the decarboxylative aldol reaction (Figure "Modified aldol tandem reaction, decarboxylative aldol reaction as an example"), where the enolate is generated via decarboxylation reaction mediated by either transition metals or organocatalysts.
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MgCl2 crystallizes in the cadmium chloride motif, which features octahedral Mg centers. Several hydrates are known with the formula MgCl2(H2O)x, and each loses water at higher temperatures: x = 12 (−16.4 °C), 8 (−3.4 °C), 6 (116.7 °C), 4 (181 °C), 2 (about 300 °C).Holleman, A. F.; Wiberg, E. Inorganic Chemistry Academic Press: San Diego, 2001. . In the hexahydrate, the Mg2+ is also octahedral, but is coordinated to six water ligands.Wells, A. F. (1984) Structural Inorganic Chemistry, Oxford: Clarendon Press. . The thermal dehydration of the hydrates MgCl2(H2O)x (x = 6, 12) does not occur straightforwardly.See notes in Rieke, R. D.; Bales, S. E.; Hudnall, P. M.; Burns, T. P.; Poindexter, G. S. "Highly Reactive Magnesium for the Preparation of Grignard Reagents: 1-Norbornane Acid", Organic Syntheses, Collected Volume 6, p. 845 (1988).
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Relative to theanine, the opposite (D-, R-) enantiomer is largely absent from the literature, except implicitly. While natural extracts that are not harshly treated are presumed to contain only the biosynthetic L\- enantiomeric form, mishandled isolates and racemic chemical preparations of theanines necessarily contain both theanine and its D-enantiomer (and from racemic syntheses, in equal proportion), and studies have suggested that the D-isomer may actually predominate in some commercial supplement preparations. Amino acid racemization in aqueous media is a well- established chemical process promoted by elevated temperature and non-neutral pH values; prolonged heating of Camellia extracts—possible for oversteeped teas and in undisclosed commercial preparative processes—has been reported to result in increasing racemization of theanine to give increasing proportions of the nonnatural D-theanine, up to equal proportions of each enantiomer.
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Hydrocyanation is important due to the versatility of alkyl nitriles (RCN), which are important intermediates for the syntheses of amides, amines, carboxylic acids and esters. The most important industrial application is the nickel-catalyzed synthesis of adiponitrile (NC-(CH2)4-CN) synthesis from buta-1,3-diene (CH2=CH-CH=CH2). Adiponitrile is a precursor to hexamethylenediamine (H2N-(CH2)6-NH2), which is used for the production of certain kinds of Nylon. The DuPont ADN process to give adiponitrile is shown below: :Butadiene hydrocyanation This process consists of three steps: hydrocyanation of butadiene to a mixture of 2-methyl-butene-3-nitrile (2M3BM) and pentene-3-nitrile (3PN), an isomerization step from 2M3BM (not desired) to 3PN and a second hydrocyanation (aided by a Lewis acid cocatalyst such as aluminium trichloride or triphenylboron) to adiponitrile.
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The first synthesis of mercury thiocyanate was probably completed in 1821 by Jöns Jacob Berzelius: :HgO + 2 HSCN -> Hg(SCN)2 \+ H2O Evidence for the first pure sample was presented in 1866 prepared by a chemist named Otto Hermes. It is prepared by treating solutions containing mercury(II) and thiocyanate ions. The low solubility product of mercury thiocyanate causes it to precipitate from solution. Most syntheses are achieved by precipitation: :Hg(NO3)2 \+ 2 KSCN -> Hg(SCN)2 \+ 2KNO3 The compound adopts a polymeric structure with Hg2+ centers linearly coordinated to two S atoms with a distance of 2.381 Å. Four weak Hg2+\--N interactions are indicated with distances of 2.81 Å.Beauchamp, A.L.; Goutier, D. "Structure cristalline et moleculaire du thiocyanate mercurique" Canadian Journal of Chemistry 1972, volume 50, p977-p981.
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Vedejs also tackled a wide range of methodologies aimed at stereoselective synthesis including protonation of carbanions, acylation and alkylation of achiral and prochiral nucleophiles, parallel kinetic resolution, and control of configuration by crystallization-induced asymmetric transformation. Over the course of his career, Vedejs published over 230 peer- reviewed articles. He served as an associate editor of the Journal of the American Chemical Society from 1994 to 1999, as chair of the NIH Medicinal Chemistry Study Section from 1990 to 1991, as chair of the Organic Division of the American Chemical Society in 2003, and as a member of the Organic Syntheses Board of Editors from 1980 to 1988. He served as editor (along with Scott E. Denmark) of the three volume series Lewis Base Catalysis in Organic Synthesis.
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Chemist Stephen Berry explained Kenyon and Steinman's theory as "describing the following causal chain: the properties of the chemical elements dictate the types of monomers that can be formed in prebiotic syntheses, which then dictate the properties of the occurring polymers, which finally dictate the properties of the first eobionts and all succeeding cells.""Biochemical Predestination" as Heuristic Principle for Understanding the Origin of Life" by Stephen Berry, J. Chem. Educ., 1997, 74 (8), p. 950 Link Kenyon's work was about virus production."Prof Flips Theory Coin About Virus Production," Winnipeg Free Press, Wednesday, March 22, 1972. p. 43 During the 1969–1970 academic year he was "on a fellowship at the Graduate Theological Union in Berkeley, where he reviewed the contemporary literature on the relationship of science and religion.
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Relatively pure YBCO was first synthesized by heating a mixture of the metal carbonates at temperatures between 1000 and 1300 K. :4 BaCO3 \+ Y2(CO3)3 \+ 6 CuCO3 \+ (1/2−x) O2 → 2 YBa2Cu3O7−x \+ 13 CO2 Modern syntheses of YBCO use the corresponding oxides and nitrates. The superconducting properties of YBa2Cu3O7−x are sensitive to the value of x, its oxygen content. Only those materials with 0 ≤ x ≤ 0.65 are superconducting below Tc, and when x ~ 0.07, the material superconducts at the highest temperature of 95 K, or in highest magnetic fields: 120 T for B perpendicular and 250 T for B parallel to the CuO2 planes. In addition to being sensitive to the stoichiometry of oxygen, the properties of YBCO are influenced by the crystallization methods used.
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VCl3 is prepared by heating VCl4 at 160–170 °C under a flowing stream of inert gas, which sweeps out the Cl2. The bright red liquid converts to a purple solid. Heating of VCl3 decomposes with volatilization of VCl4, leaving VCl2.Young, R. C.; Smith, M. E. "Vanadium(III) Chloride" Inorganic Syntheses volume IV, page 128–130, 1953. Upon heating under H2 at 675 °C (but less than 700 °C), VCl3 reduces to greenish VCl2. :: 2 VCl3 \+ H2 → 2 VCl2 \+ 2 HCl Comproportionation of vanadium trichloride and vanadium(V) oxides gives vanadium oxydichloride: :V2O5 \+ VOCl3 \+ 3 VCl3 → 6 VOCl2 Vanadium trichloride catalyses the pinacol coupling reaction of benzaldehyde (PhCHO) to 1,2-diphenyl-1,2-ethanediol by various reducing metals such as zinc:Vanadium-Catalyzed Pinacol Coupling Reaction in Water Xiaoliang Xu and Toshikazu Hirao J. Org. Chem.
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Application of the [4+4] photocycloaddition is scarce because of competition with the [2+2] cycloaddition. However, when accessible, this method can be used to build 8-membered ring with complex stereocenters and structures in one step, as is seen in proposed syntheses for Taxol and molecules of the fusicoccin family. Additionally, while this reaction first forms fused rings, subsequent cleavages can afford macrocycles. Forming the BC rings of Taxol In this partial synthesis of the BC rings of Taxol, the framework buildup utilized an intramolecule [4+4] photocycloaddition of a relatively linear and simple 2-pyridone derivative, folding it into the desired fused rings with correct stereochemistry at C3, C8, and C15 (compare with Taxol on the right) and two double bonds on the B ring ready to accept trans-addition.
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The Tsuji–Trost reaction (also called the Trost allylic alkylation or allylic alkylation) is a palladium-catalysed substitution reaction involving a substrate that contains a leaving group in an allylic position. The palladium catalyst first coordinates with the allyl group and then undergoes oxidative addition, forming the -allyl complex. This allyl complex can then be attacked by a nucleophile, resulting in the substituted product.Strategic Applications of Named Reactions in Organic Synthesis (Paperback) by Laszlo Kurti, Barbara Czako Tsuji–Trost allylation This work was first pioneered by Jiro Tsuji in 1965Organic syntheses by means of noble metal compounds XVII. Reaction of -allylpalladium chloride with nucleophiles Tetrahedron Letters, Volume 6, Issue 49, 1965, Pages 4387-4388 Jiro Tsuji, Hidetaka Takahashi, Masanobu Morikawa and, later, adapted by Barry Trost in 1973 with the introduction of phosphine ligands.
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"Macro- Structure in Carl Ruggles's Sun-Treader: A Fearful Symmetry", Sonus, Vol.15, No.2 Spring 1995 Carl’s music until 1997 tends to explore different styles, and to create unusual syntheses thereof. A history major as an undergraduate at Yale University, he has felt that the musical past is a fertile source to be manipulated for new expressive purposes. Duke Meets Mort (1992) is a saxophone quartet that interprets the harmonic changes of Duke Ellington’s Mood Indigo in the voice of Morton Feldman. Time/Memory/Shadow (1988) is a double trio (piano quintet and harp) based on a march written in the composer’s adolescence, which is slowly “excavated” in the course of the piece, and only revealed at the end. From 1998, starting with Open for string trio, Carl’s music has become less referential.
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In the 1950s, Gellner discovered his great love of social anthropology. Chris Hann, director of the Max Planck Institute for Social Anthropology, writes that following the hard-nosed empiricism of Bronisław Malinowski, Gellner made major contributions to the subject over the next 40 years, ranging from "conceptual critiques in the analysis of kinship to frameworks for understanding political order outside the state in tribal Morocco (Saints of the Atlas, 1969); from sympathetic exposition of the works of Soviet Marxist anthropologists to elegant syntheses of the Durkheimian and Weberian traditions in western social theory; and from grand elaboration of 'the structure of human history' to path-breaking analyses of ethnicity and nationalism (Thought and Change, 1964; Nations and Nationalism, 1983)". He also developed a friendship with the Moroccan-French sociologist Paul Pascon, whose work he admired.
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Molecular Design Limited (MDL) was founded by Stuart Marson and W. Todd Wipke in 1978, following the latter's experience with E. J. Corey in developing software for planning organic syntheses. The company developed software to store and search chemical structures in large databases under the brand name MACCS (Molecular ACCess System), which was targeted at pharmaceutical and agrochemical companies. MDL offered their ISIS (Integrated Scientific Information System) products including ISIS/Draw as components of the MACCS system, specifically to allow chemists to use a graphical interface to register new compounds into corporate databases and to search these databases by structure or part-structure. They also introduced ISIS/Base, a chemical database program suited to the storage of relatively small numbers of structures with associated data for personal use independently of corporate systems.
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Schreiber started his research work in organic synthesis, focusing on concepts such as the use of [2 + 2] photocycloadditions to establish stereochemistry in complex molecules, the fragmentation of hydroperoxides to produce macrolides, ancillary stereocontrol, group selectivity and two-directional synthesis. Notable accomplishments include the total syntheses of complex natural products such as talaromycin B, asteltoxin, avenaciolide, gloeosporone, hikizimicin, mycoticin A, epoxydictymene and the immunosuppressant FK-506. Following his work on the FK506-binding protein FKBP12 in 1988, Schreiber reported that the small molecules FK506 and cyclosporin inhibit the activity of the phosphatase calcineurin by forming the ternary complexes FKBP12-FK506-calcineurin and cyclophilin-ciclosporin-calcineurin. This work, together with work by Gerald Crabtree at Stanford University concerning the NFAT proteins, led to the elucidation of the calcium-calcineurin-NFAT signaling pathway.
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He received the 26th Chemical Society of Japan Award for Distinguished Young Chemists (Allylsilanes in Organic Synthesis) in 1977, the 6th Inoue Award for Science (Organic Synthesis Using Organosilicon Compounds) in 1990, the 39th Society of Synthetic Organic Chemistry Award, Japan (Fine Organic Synthesis Using Organometallics) in 1997, and the 55th Chemical Society of Japan Award (Development of New Reagents of Silicon and Related Metals and Application to the Practical Organic Synthesis) in 2003,Recipients of the CSJ Award (2011–2000), Chemical Society of Japan, retrieved 2012-06-29, and the Society of Silicon Chemistry JAPAN Award 2012 (Development on New Reagents of Silicon and Related Metals and their Applications to Practical Organic Syntheses). In 2008 he got an honor of the Fellow of the Chemical Society of Japan.
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The structure of vitamin B12 was the first low-molecular weight natural product determined by x-ray analysis rather than by chemical degradation. Thus, while the structure of this novel type of complex biomolecule was established, its chemistry remained essentially unknown; exploration of this chemistry became one of the tasks of the vitamin's chemical synthesis. In the 1960s, synthesis of such an exceptionally complex and unique structure presented the major challenge at the frontier of research in organic natural product synthesis. Figure 2: The two ETH corrin model syntheses Figure 3: The two approaches to cobyric acid synthesis Already in 1960, the research group of the biochemist in Stuttgart had reconstituted vitamin B12 from one of its naturally occurring derivatives, cobyric acid, by stepwise construction of the vitamin's nucleotide loop.
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The interaction and syntheses between different cultures, the arbitrariness of national identity, and irreverence towards ethnocentric, patriotic or nationalistic sentiment are recurring themes in Jarmusch's work. Jarmusch's fascination for music is another characteristic that is readily apparent in his work. Musicians appear frequently in key roles – John Lurie, Tom Waits, Gary Farmer, Youki Kudoh, RZA and Iggy Pop have featured in multiple Jarmusch films, while Joe Strummer and Screamin' Jay Hawkins appear in Mystery Train and GZA, Jack and Meg White feature in Coffee and Cigarettes. Hawkins' song "I Put a Spell on You" was central to the plot of Stranger than Paradise, while Mystery Train is inspired by and named after a song popularized by Elvis Presley, who is also the subject of a vignette in Coffee and Cigarettes.
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In the 1990–1993 he published, as editor, the historical journals "Patrimoniu" "Magazine of History of Moldova." He published a number of studies and books on various historical subjects: the political events in Bessarabia in 1917-1918, Bessarabian agrarian relations during the interwar period, the Bessarabian famine of 1946-1947, the resistance movement against Soviet occupation of Bessarabia during 1944-1953, political and ethnic relations east of the Carpathians in the period preceding the founding of the Romanian state of Moldova, the Greco-Roman antiquity on the Lower Dniester and the neighboring territories, the philosophy of history from the perspective of some Romanian thinkers, historical bibliography of Bessarabia and Transnistria, social and political realities in modern Moldova etc. He wrote several syntheses of Romanian history. He also had some literary preoccupations, which occurred occasionally and with great interruptions.
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Her study of the chemistry of the anthocyanin pigments culminated in publication of her first book in 1916, The Anthocyanin Pigments of Plants. This application of chemical analysis to explain genetic data led to international recognition since it was among the first attempts at syntheses of these two areas. She was an assistant lecturer in Newnham College between 1906 and 1908. She left Cambridge University between 1911 and 1914 because she held a studentship at the John Innes Horticultural Institution where, in addition to her laboratory work, she was valued as the Institution's leading botanical artist, able to capture the exact colours of plants. During this time in 1913 she became one of the first three women to be elected to the Biochemical Club (later to be known as the Biochemical Society) after the club's initial exclusion of women in 1911.
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In 1888, Walden graduated from the University with a degree in chemical engineering and continued working at the Chemistry Department as an assistant to professor C. Bischof. Under his guidance, Walden began compiling "Handbook of Stereochemistry" which was published in 1894. In preparation of this handbook, Walden had to perform numerous chemical syntheses and characterizations which resulted in 57 journal papers on stereochemistry alone, published between 1889 and 1900 in Russian and foreign journals 57 articles on the stereochemistry. He also continued his research in the field of physical chemistry, establishing in 1889 that the ionizing power of non- aqueous solvent is directly proportional to the dielectric constant. During the summer vacations of 1890 and 1891, Walden was visiting Ostwald at the University of Leipzig and in September 1891 defended there a master thesis on the affinity values of certain organic acids.
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Hence, it was not necessary to do anything specific to promote the required sequence of 8π conrotatory and 6π disrotatory cyclizations (further highlighted in supplementary image); they occurred spontaneously on generation of tetraene-diol 15. Protection of a single alcohol moiety (as TBDPS) was accomplished using the silyl chloride via the corresponding tricyclic iodoether intermediate (not shown), with the internally masked remaining hydroxyl group being released on treatment with zinc dust in acetic acid (giving 18 in 70-80% yield). Bromination of the alcohol under Appel conditions followed by its displacement on treatment with sodium cyanide in HMPA gave nitrile 20, the key intermediate in all of this group's endiandric acid syntheses. The title compound was then pursued via DIBAL reduction of the nitrile at low temperature, followed by mild acidic hydrolysis to release aldehyde 21.
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The three-dimensional structures of various proteins including lactoperoxidase, peptidoglycan recognition protein, lactoferrin from several species, ribosome inactivating proteins, bifunctional inhibitor proteins from plant seeds and various serine proteases and their inhibitors have been determined by his group. The elaborate structural studies of proteins from several important systems as potential drug targets such as phospholipase A2, cyclooxygenase, lipoxygenase, endothelin receptor, endothelin converting enzyme, breast cancer regression proteins and matrix metanosomal proteins as well as their complexes with natural and designed synthetic ligands have been carried out. He had developed the rules of peptide design with alpha, beta – dehydro - amino acids through extensive studies using syntheses, and X-ray and NMR structure determinations. These design rules are being exploited for making specific peptides to act as tight inhibitors of target enzymes and potent antagonists of target receptors for eventually leading to useful therapeutic agents.
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Once this is formed the other carbonyl containing starting material will coordinate in the manner shown below and give the product after protonation.) The benefits of the Reformatsky reaction over the conventional aldol reaction protocols is the following: # Allows for exceedingly derivatized ketone substrates # The ester enolate intermediate can be formed in the presence of enolizable moieties # Well suited for intramolecular reactions Below shows the six-membered transition state of the Zimmerman–Traxler model (Chelation Control, see Aldol reaction), in which R3 is smaller than R4.Kurti, L.; Czako, B. ‘‘Strategic Applications of Named Reactions in Organic Synthesis’’; Elsevier: Burlington, 2005. The Reformatsky reaction has been employed in numerous total syntheses such as the synthesis of C(16),C(18)-bis-epi-cytochalasin D: The Reformatsky reaction even allows for with zinc homo-enolates.Kumwaijima,I.; et al.
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Another attempt was made by Wiechert, who treated HF with dichromate, yielding impure liquid CrO2F2 at −40 °C. Engelbrecht and von Grosse's synthesis of CrO2F2, and most successive syntheses, involve treating chromium trioxide with a fluorinating agent: :CrO3 \+ 2 HF → CrO2F2 \+ H2O The reaction is reversible, as water will readily hydrolyze CrO2F2 back to CrO3. The approach published by Georg Brauer in the Handbook of Preparative Inorganic Chemistry drew on von Wartenberg's approach of direct fluoridation: :CrO2Cl2 \+ F2 → CrO2F2 \+ Cl2 Other methods include treatment with chlorine fluoride, carbonyl fluoride, or some metal hexafluorides: :CrO3 \+ 2 ClF → CrO2F2 \+ Cl2 \+ O2 :CrO3 \+ COF2 → CrO2F2 \+ CO2 :CrO3 \+ MF6 → CrO2F2 \+ MOF4 (M = Mo, W) The last method involving the fluorides of tungsten and molybdenum are reported by Green and Gard to be very simple and effective routes to large quantities of pure CrO2F2.
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CerS were originally called Lass (Longevity assurance) genes because of their homology to the yeast protein, longevity assurance gene-1 (LAG1p), and they were later renamed due to the discovery of their biological function. LAG1 in yeast was discovered in 1994 and named for the discovery that its deletion prolonged life span of Saccharomyces cerevisiae by almost 50%. In the following years, it and its homologs were shown to be required for the syntheses of ceramides found in yeast. Three years previously, the mammalian gene upstream of growth and differentiation factor-1 (UOG-1) was discovered, but it wasn't until 2005 that it was defined as the first mammalian CerS, when Sujoy Lahiri and Tony Futerman from the Weizmann Institute of Science found that LASS5 is a bona fide mammalian ceramide synthase that specifically synthesizes palmitoyl (C16) ceramide.
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To that end, Fowler and coworkers installed a carbonyl group on the nitrogen, hypothesizing that the lone pair of the nitrogen would be stabilized by participation in an amide bond, and that the electronegativity of this amide group would lower the LUMO of the imine group, making the transition state more favorable. Using this strategy, Fowler and coworkers were able to use the 1-aza-Cope rearrangement to create piperidine and pyridine derivatives. This strategy was shown to be relatively robust, allowing for the formation of products even when forced through a boat transition state, when perturbed with substituent effects, or put in competition with alternative rearrangements. Also significant is the relative ease of production of the reactants, which uses a Diels-Alder reaction paired with relatively simple workup steps, allowing for syntheses using complex cycling.
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Barrett has invented many reactions including novel glycosidations, atom-economic aromatic substitution reactions, metal-catalyzed oxidations and hydroaminations, reactions using ROMP-gel supported reagents and multi-component benzyne coupling reactions. He has contributed extensively to the synthesis of β-lactams using alkenyl anions, ynolates, novel isocyanates, iron vinylidines, heteroatom functionalized nitroalkenes, and ring closing alkene and enyne metathesis reactions. He has completed the total synthesis of diverse bioactive natural products including papulacandin D, papuamine, showdomycin, milbemycin β3, the palmarumycins and preussomerin G, (+)-calyculin A and the multiple cyclopropane CETP inhibitor U-106305 and structurally related cyclopropane nucleoside FR-900848 and coronanes. He has also published highly flexible methods for the biomimetic total syntheses of resorcylate and meroterpenoid natural products including 15G256β, aigialomycin D, LL-Z1640-2, cruentaren A, hericenone J and macrosporin, amorphastilbol, (+)-hongoquercin A and B, and austalides.
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Following the original method, photolysis of an acetic acid solution of Fe(CO)5 produces Fe2(CO)9 in good yield:King, R. B. Organometallic Syntheses. Volume 1 Transition-Metal Compounds; Academic Press: New York, 1965. . :2 Fe(CO)5 → Fe2(CO)9 \+ CO Fe2(CO)9 consists of a pair of Fe(CO)3 centers linked by three bridging CO ligands. Although older textbooks show an Fe-Fe bond consistent with the 18 electron rule (8 valence electrons from Fe, two each from the terminal carbonyls, one each from the bridging carbonyls and one from the other Fe atom in the metal-metal bond), theoretical analyses have consistently indicated the absence of a direct Fe-Fe bond:Jennifer C. Green, Malcolm L. H. Green, Gerard Parkin "The occurrence and representation of three-centre two-electron bonds in covalent inorganic compounds" Chem. Commun.
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The three main structures phospholipids form in solution; the liposome (a closed bilayer), the micelle and the bilayer. In 1954 and 1958 Krishna Bahadur and co-workers published the successful synthesis of amino acids from a mixture of paraformaldehyde, colloidal molybdenum oxide or potassium nitrate and ferric chloride under sunlight. It appears that this experimental approach was seminal for the assays to produce Jeewanu, which he first reported in 1963 in an obscure Indian journal, Vijnana Parishad Anusandhan Patrika. His detailed syntheses were published in Germany in 1964 in a series of articles. Their initial experiment consisted of a sterilised apparatus in which inorganic nitrogenous compounds (such as ammonium phosphate and ammonium molybdate) and organic compounds such as citric acid (C6H8O7), paraformaldehyde (OH(CH2O)nH) and formaldehyde (CH2O) for carbon sources were mixed with minerals commonly found in living cells.
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Carlist standard As a historian del Burgo focused on – if not limited himself to – Carlism and Navarre, with a clear preference for the 19th and 20th centuries and for the history of foralism. His works range from syntheses to monographs, biographies and case studies. As an amateur with no systematic training, he did not adhere to any specific methodology,Garralda Arizcun 2008 though he remained chiefly within the limits of political history and based his studies on thorough research in primary sources, mostly the printed ones. Del Burgo's key historical work is the monumental Bibliografía de las guerras carlistas (1953-1966), the opus which spanned across 5 volumes, cost 25 years of workit was this work which earned del Burgo the national literary prize in 1967, Garralda Arizcun 2008 and indexed more that 10,000 works; until today it remains a point of reference for all students of the subject.
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Jhillu Singh Yadav (born 1950) is an Indian organic chemist and the co-founder of the Indo-French Joint Laboratory for Sustainable Chemistry at Interfaces (JLSCI), jointly established by the Indian Institute of Chemical Technology and the University of Rennes 1. He is a former director of Indian Institute of Chemical Technology (IICT) and is known for his studies on organic syntheses of allylic and acetylenic alcohols and spiroacetals. He is an elected fellow of the Indian National Science Academy, the Indian Academy of Sciences National Academy of Sciences, India, Indian Institute of Chemical Engineers and The World Academy of Sciences. The Council of Scientific and Industrial Research, the apex agency of the Government of India for scientific research, awarded him the Shanti Swarup Bhatnagar Prize for Science and Technology, one of the highest Indian science awards, in 1991, for his contributions to chemical sciences.
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6, Georg Thieme Verlag, Stuttgart, 1997. PrCl3 forms a stable Lewis acid-base complex K2PrCl5 by reaction with potassium chloride; this compound shows interesting optical and magnetic properties.J. Cybinska, J. Sokolnicki, J. Legendziewicz, G. Meyer, Journal of Alloys and Compounds, 341, 115–123 (2002). Aqueous solutions of praseodymium(III) chloride can be used to prepare insoluble praseodymium(III) compounds. For example, praseodymium(III) phosphate and praseodymium(III) fluoride can be prepared by reaction with potassium phosphate and sodium fluoride, respectively: :PrCl3 \+ K3PO4 → PrPO4 \+ 3 KCl :PrCl3 \+ 3 NaF → PrF3 \+ 3 NaCl :2PrCl3 \+ 3 Na2CO3\----> Pr2CO3 \+ 6NaCl When heated with alkali metal chlorides, it forms a series of ternary (compounds containing three different elements) materials with the formulae MPr2Cl7, M3PrCl6, M2PrCl5, and M3Pr2Cl9 where M = K, Rb, Cs.Gerd Meyer, "Ternary Chlorides and Bromides of the Rare-Earth Elements", Inorganic Syntheses, 1990, Volume 30, pp. 72–81.
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After an introductory first chapter, the next five chapters focus on Vijñānabhikṣu's philosophical syntheses. Chapter 2, entitled "An Alternate History of Vedanta", sets the stage by tracing the history of Bhedābheda Vedānta, a comparatively neglected tradition that teaches the "difference and nondifference" of Brahman and the individual self. Vijnanabhikshu's version of this "Difference and Non-Difference" Vedanta is described in Chapter 3. Chapter 4 offers a historical overview of two important non-Vedanta Indian philosophies, the schools of Sāṃkhya and Yoga, focusing on their views of God, documenting that contrary to widespread views of Sāṃkhya as entirely atheistic, most first millennium Sāṃkhya authors were theists. Chapter 5, "Reading Against the Grain of the Samkhyasutras", focuses on a controversial assertion by Vijñānabhikṣu that some Sāṃkhyasūtra verses that explicitly argue against God's existence do not ultimately intend to deny God's existence, but represent merely a “temporary concession” (abhyupagamavāda) or “bold assertion” (prauḍhivāda).
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In his 2016 Handbook of Synthetic Organic Chemistry, Michael Pirrung wrote that yield is one of the primary factors synthetic chemists must consider in evaluating a synthetic method or a particular transformation in "multistep syntheses." He wrote that a yield based on recovered starting material (BRSM) or (BORSM) does not provide the theoretical yield or the "100% of the amount of product calculated", that is necessary in order to take the next step in the multistep systhesis. Purification steps always lower the yield, through losses incurred during the transfer of material between reaction vessels and purification apparatus or imperfect separation of the product from impurities, which may necessitate the discarding of fractions deemed insufficiently pure. The yield of the product measured after purification (typically to >95% spectroscopic purity, or to sufficient purity to pass combustion analysis) is called the isolated yield of the reaction.
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Throughout the 1970s, Banana continued with parade entries, April Fool's Day events, and collaborations with Bay-area Dadaists on Dada sound poetry and Italian Futurist syntheses presented at the San Francisco Book Fair, San Jose State University and the Saturday Afternoon Club in Ukiah. In 1978, Banana and Gaglione presented their "Futurist Sound" performance in A Literal Exchange at A Space in Toronto. That fall they began a European tour arranged through Banana's mail-art network, presenting "Futurist Sound" and her Banana Olympics film in 29 cities in 11 countries. In 1979 they presented the works again at the Living Art Performance Festival in Vancouver, and in 1980 at San Francisco State University, the San Francisco Art Institute, San Jose State University, the Inter-Dada 80 Festival in Ukiah, San Diego State University, University of California, Irvine and Long Beach, and the LA Dada festival in Los Angeles.
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Many metabolites found in nature contain alkyne or enyne moieties, and therefore, the Sonogashira reaction has found frequent utility in their syntheses. Several of the most recent and promising applications of this coupling methodology toward the total synthesis of natural products exclusively employed the typical copper-cocatalyzed reaction. An example of the coupling of an aryl iodide to an aryl acetylene can be seen in the reaction of the iodinated alcohol and the tris(isopropyl)silylacetylene, which gave alkyne, an intermediate in the total synthesis of the benzindenoazepine alkaloid bulgaramine. There are other recent examples of the use of aryl iodides for the preparation of intermediates under typical Sonogashira conditions, which, after cyclization, yield natural products such as benzylisoquinoline Mujahidin, D.; Doye, S. Eur Journal of Organic Chemistry 2005, 2689 or indole alkaloids An example is the synthesis of the benzylisoquinoline alkaloids (+)-(S)-laudanosine and (–)-(S)-xylopinine.
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Further studies of a single crystal of alacranite with dimensions 30 × 60 × 120 mm was examined using direct methods, Fourier syntheses and structure refinement resulting in intensities violating the C lattice type and symmetries like h0l reflections with l = 2n + 1 were absent. These results confirm the P2/c space group of alacranite resulting in a structure of two different kinds of cage-like molecules that are packing closely and found in the β-phase. The first molecule is identical to the As4S4 which is realgar where every As atom links one As and two S atoms and that is determined in the structure of the β-phase and realgar. The second molecule in the structure of alacranite is found to be chemically and structurally identical to As4S5 which is uzonite. Upon exposure to light, As4S4 molecule expands its unit cell volume and hence, transfers to As4S5.
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The spontaneous confluence of artists at the via Cavour studio does not appear to have been led by true and proper programmes or manifestos, but rather by friendship, cultural syntheses and a singular pictorial cohesion. With their firm approach to European expressionism, they formally contraposed the solid and orderly painting of neoclassic character, promoted by the Return to order current in the 1920s, which was particularly strong in the Italian sensibility of post-World War I. The first identification of this artistic group should be attributed to Roberto Longhi, who wrote:in L'Italia Letteraria (Literary Italy) of 7 April 1929. and added: Longhi used this definition to indicate the special work he perceived these artists to be performing within the expressionist universe, breaking off from official art movements.In the journal L'Italia Letteraria of 14 April 1929, where a concomitance with Marc Chagall is also mentioned.
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The initial development of CEON was based on the notion that early successes will be met by facilitating the activities of existing environmental sites and networks active in the Arctic and increasing the potential for integration and syntheses between sites. Example activities include promoting increased transfer of knowledge and standardization of research methods between networks and sites, and increasing accessibility to data and linkages to multidisciplinary and international programs. Accordingly, presentations on the CEON concept were made at numerous meetings of organizations/research programs active in the Arctic over a short period of time in order to establish an initial momentum for the development of CEON. Presentations focused on the necessity for the CEON initiative to meet the needs of the participating research community, science administrators, policy makers, industry, education and indigenous communities whilst providing linkages between disciplines and existing networks and connectivity spanning regional to circum-arctic and global scales.
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Sir John Warcup Cornforth Jr., AC, CBE, FRS, FAA (7 September 1917 – 8 December 2013) was an AustralianBritish chemist who won the Nobel Prize in Chemistry in 1975 for his work on the stereochemistry of enzyme-catalysed reactions, becoming the only Nobel laureate born in New South Wales. Cornforth investigated enzymes that catalyse changes in organic compounds, the substrates, by taking the place of hydrogen atoms in a substrate's chains and rings. In his syntheses and descriptions of the structure of various terpenes, olefins, and steroids, Cornforth determined specifically which cluster of hydrogen atoms in a substrate were replaced by an enzyme to effect a given change in the substrate, allowing him to detail the biosynthesis of cholesterol.Deaf Scientist Corner – John Warcup Cornforth, Texas Woman's University For this work, he won a share of the Nobel Prize in Chemistry in 1975, alongside co-recipient Vladimir Prelog, and was knighted in 1977.
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Carbon tetrachloride was originally synthesized by the French chemist Henri Victor Regnault in 1839 by the reaction of chloroform with chlorine,V. Regnault (1839) "Sur les chlorures de carbone CCl et CCl2" (On the chlorides of carbon CCl and CCl2 ), Annales de Chimie et de Physique, vol. 70, pages 104-107. Reprinted in German as: but now it is mainly produced from methane: :CH4 \+ 4 Cl2 → CCl4 \+ 4 HCl The production often utilizes by-products of other chlorination reactions, such as from the syntheses of dichloromethane and chloroform. Higher chlorocarbons are also subjected to "chlorinolysis": :C2Cl6 \+ Cl2 → 2 CCl4 Prior to the 1950s, carbon tetrachloride was manufactured by the chlorination of carbon disulfide at 105 to 130 °C: :CS2 \+ 3Cl2 → CCl4 \+ S2Cl2 The production of carbon tetrachloride has steeply declined since the 1980s due to environmental concerns and the decreased demand for CFCs, which were derived from carbon tetrachloride.
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Numerous modernist poets have written in non-traditional forms or in what traditionally would have been considered prose, although their writing was generally infused with poetic diction and often with rhythm and tone established by non-metrical means. While there was a substantial formalist reaction within the modernist schools to the breakdown of structure, this reaction focused as much on the development of new formal structures and syntheses as on the revival of older forms and structures. Postmodernism goes beyond modernism's emphasis on the creative role of the poet, to emphasize the role of the reader of a text (hermeneutics), and to highlight the complex cultural web within which a poem is read. Today, throughout the world, poetry often incorporates poetic form and diction from other cultures and from the past, further confounding attempts at definition and classification that once made sense within a tradition such as the Western canon.
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Yu. S. Kosenkova, M.P. Polovinka, N.I. Komarova, D.V. Korchagina, N. Yu. Kurochkina, V.A. Cheremushkina and N.F. Salakhutdinov, Chemistry for Sustainable Development, 2009, 17, pages 507-511 (article) in Reboulia hemisphaericaRiccardinC, a novel cyclic bibenzyl derivative from Reboulia hemisphaerica. Yoshinori Asakawa, Reiko Matsuda, Phytochemistry, Volume 21, Issue 8, 1982, Pages 2143–2144, and in the Chinese liverwort Plagiochasma intermedium.Antifungal macrocyclic bis(bibenzyls) from the Chinese liverwort Ptagiochasm intermedlum L. Chun-Feng Xie, Jian-Bo Qu, Xiu-Zhen Wu, Na Liu, Mei Ji and Hong-Xiang Lou, Natural Product Research: Formerly Natural Product Letters, 2010, Volume 24, Issue 6, pages 515-520, In 2005, the compound was prepared by total synthesis together with the strained compound cavicularin.Kostiuk, S. L., Woodcock, T., Dudin, L. F., Howes, P. D. and Harrowven, D. C. (2011), Unified Syntheses of Cavicularin and Riccardin C: Addressing the Synthesis of an Arene Adopting a Boat Configuration.
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Trifluoroperacetic acid can be easily prepared by an Organic Syntheses process of treating trifluoroacetic anhydride with a concentrated (90%) aqueous solution of hydrogen peroxide: : \+ -> \+ As the anhydride will form trifluoroacetic acid in contact with water, an excess of the anhydride also serves to remove the solvent from the peroxide reactant: : \+ -> 2 A more dilute hydrogen peroxide solution (30%) can be used to form trifluoroperacetic acid for some reactions from trifluoroacetic acid. : \+ -> \+ In order to avoid the danger of handling pure or highly concentrated solutions of hydrogen peroxide, hydrogen peroxide – urea can be used to give the peracid. This method involves no water, so it gives a completely anhydrous peracid, which is an advantage when the presence of water leads to side reactions during certain oxidation reactions. : \+ -> \+ \+ In cases where a pH buffering agent is needed for a synthesis and where the presence of water is tolerated, another approach has been developed.
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More dependable and scalable procedures have been developed, two examples being the syntheses of McCarry and Varasi. McCarry’s synthesis is a three step synthesis involving a lithium acetylide produced from propargyl chloride. The acetylide (3), was dissolved in ether, cooled to -40°C, and treated with excess propargyl chloride to afford ethyl 4-chlorotetrolate (4) in a 70% yield. (4) was then added to a solution of water, methanol and hydroxylamine at -35°C . At a pH of between 8.5 and 9, the isoxazole (5) was recovered in a 41% yield. Muscimol was formed in a 65% yield when (5) was dissolved in a saturated solution of methanol and anhydrous ammonia and heated from 0°C to 50°C. The total yield was 18.7%. 750px Varasi’s synthesis is notable for its inexpensive starting materials and mild conditions. It begins with the combination of 2,3-Dichloro-1-propene (6), potassium bicarbonate, water, and dibromoformaldoxime (7), all dissolved in ethyl acetate.
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Some of the texts describe Helios Mithras navigating the Sun's path not in a chariot but in a boat, an apparent identification with the Egyptian sun god Ra. Helios is also described as "restraining the serpent", likely a reference to Apophis, the serpent god who, in Egyptian myth, is said to attack Ra's ship during his nightly journey through the underworld. In many of the Papyri, Helios is also strongly identified with Iao, a name derived from that of the Hebrew god Yahweh, and shares several of his titles including Sabaoth and Adonai. He is also assimilated as the Agathos Daemon (called "the Agathodaimon, the god of the gods"), who is also identified elsewhere in the texts as "the greatest god, lord Horus Harpokrates". The Neoplatonist philosophers Proclus and Iamblichus attempted to interpret many of the syntheses found in the Greek Magical Papyri and other writings that regarded Helios as all-encompassing, with the attributes of many other divine entities.
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Triphenyl phosphite is the chemical compound with the formula P(OC6H5)3. This colourless viscous liquid is the ester of phosphorous acid and phenol. It is used as a ligand in organometallic chemistry. Nickel complexes of this ligand are homogeneous catalysts for the hydrocyanation of alkenes. Triphenylphosphite is prepared from phosphorus trichloride and phenol in the presence of a base: :PCl3 \+ 3 HOC6H5 → P(OC6H5)3 \+ 3 HCl Trimethylphosphine is prepared from triphenylphosphite:Leutkens, Jr., M. L.; Sattelberger, A. P.; Murray, H. H.; Basil, J. D.; Fackler, Jr., J. P. "Trimethylphosphine" Inorganic Syntheses, 1990, volume 28, pages 305-310. : 3 CH3MgBr + P(OC6H5)3 → P(CH3)3 \+ 3 MgBrOC6H5 Triphenylphosphite is a notable example of polyamorphism in organic compounds, namely it exists in two different amorphous forms at temperatures about 200 K. Not long ago a new long-awaited polymorphic modification of triphenyl phosphite was obtained by means of crystallization in ionic liquidsD.
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The chemical properties of Os3(CO)12 have been thoroughly examined. Direct reactions of ligands with the cluster often lead to complex product distributions because the inert Os–CO bonds require high temperatures to break, and at such high temperatures the initially formed adducts react further. More successfully, Os3(CO)12 is converted to more labile derivatives such as Os3(CO)11(MeCN) and Os3(CO)10(MeCN)2 using Me3NO as a decarbonylating agent.Nicholls, J. N.; Vargas, M. D. “Some Useful Derivatives of Dodecarbonyltriosmium” Inorganic Syntheses, 1990, volume 28, pages 232–235. . Os3(CO)11(MeCN) reacts with a variety of even weakly basic ligands to form adducts such as Os3(CO)11(ethylene) and Os3(CO)11(pyridine). The direct reaction of Os3(CO)12 with ethylene and pyridine results in degradation of these organic ligands to give the vinyl hydride HOs3(CO)10(η1,η2-C2H3) and the pyridyl-hydride HOs3(CO)10(NC5H4).
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As of 2003, the Russian Ministry of Justice had registered forty Rodnover organisations, while there were "probably several hundred of them in existence". The historian Marlène Laruelle similarly noted that Rodnovery in Russia has spread mostly among the young people and the cultivated middle classes, that portion of Russian society interested in the post-Soviet revival of faith but turned off by Orthodox Christianity, "which is very institutionalized" and "out of tune with the modern world", and "is not appealing [to these people] because it expects its faithful to comply with normative beliefs without room for interpretation". Rodnovery is attractive because of its "paradoxical conjunction" of tradition and modernity, recovery of the past through innovative syntheses, and its values calling for a rediscovery of the true relationship between mankind, nature and the ancestors. Rodnovery has also contributed to the diffusion of "historical themes"—particularly regarding an ancient Aryan race—to the general population, including many who were Orthodox or non-religious.
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A high proportion were also involved in specialist professions such as engineering, academia, or information technology, and the majority lived in cities. Marlène Laruelle similarly noted that Rodnovery in Russia has spread mostly among the young people and the cultivated middle classes, that portion of Russian society interested in the post-Soviet revival of faith but turned off by Orthodox Christianity, "which is very institutionalized" and "out of tune with the modern world", and "is not appealing [to these people] because it expects its faithful to comply with normative beliefs without room for interpretation". Rodnovery is attractive because of its "paradoxical conjunction" of tradition and modernity, recovery of the past through innovative syntheses, and its values calling for a rediscovery of the true relationship between mankind, nature and the ancestors. Rodnovery has also contributed to the diffusion of "historical themes"—particularly regarding an ancient Aryan race—to the general population, including many who were Orthodox or non-religious.
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Working in DMSO solvent does not allow isolation of the bicyclic ketol intermediate, it leads directly to the optically active bicyclic dione.Z. G. Hajos, D. R. Parrish, German Patent DE 2102623 (29 July 1971) and USP 3,975,440 (Aug.17, 1976) Example 21. The reaction is called the Hajos-Parrish reaction or the Hajos- Parrish-Eder-Sauer-Wiechert reaction.1 H-Indene-1,5(6 H)-dione, 2,3,7,7a-tetrahydro-7a-methyl-, (S)- Zoltan G. Hajos and David R. Parrish Organic Syntheses, Coll. Vol. 7, p.363 (1990); Vol. 63, p.26 (1985) Article Identical reaction with 2-methyl-1,3-cyclopentanedione (5 membered ring instead of a 6 membered ring) This reaction has also been performed in a one- step procedure, leading to 49% yield and 76% Enantiomeric excess (ee):A proline-catalyzed asymmetric Robinson annulation reaction Tetrahedron Letters, Volume 41, Issue 36, September 2000, Pages 6951-6954 Tommy Bui and Carlos F. Barbas :Wieland Miescher Barbas 2000 Other proline-based catalysts have been investigated Org. Synth.
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The Faculty’s academic staff have excelled in many areas of research, particularly those that are relevant to the national and regional needs. Major research projects undertaken by biomedical science groups involve the application of innovative biotechnology and genetic engineering techniques for the diagnosis, prevention and treatment of tropical diseases in humans and animals, i.e. malaria, melioidosis, schistosomiasis, filariasis, liver flukes, babesiosis, dengue and thalassemia; the reproduction of cattle and important food and medical substances for man and animals from indigenous natural materials; the control and improvement of the environment. The physical science groups have engaged in many important research projects, such as the studies of physico-chemical properties and utilization of liquid crystals, natural and synthetic polymers, the development of ferrite-polymer composites for industrial applications, chemistry and applications of natural products, organic syntheses of drugs for tropical diseases and other useful compounds, and the use of computers in chemistry, chemical physics and mathematical modeling.
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Focusing on the arsenic center, the molecule geometry is trigonal pyramidal with the Cl-As-Cl and C-As-Cl angles approaching 90° (see image). Virtually all related arsenic(III) compounds adopt similar structures. Methyldichloroarsine is produced by the reaction of methylmagnesium chloride and arsenic trichloride: :AsCl3 \+ CH3MgCl → CH3AsCl2 \+ MgCl2 Typically such syntheses are conducted in ether or THF solutions and typically the product is isolated by distillation. Use of larger amounts of the magnesium reagent affords greater amounts of dimethylchloroarsine ((CH3)2AsCl) and trimethylarsine ((CH3)3As). In World War I, the German manufacturing method consisted of a three-step reaction beginning with methylation of sodium arsenite: :2 Na3AsO3 \+ (CH3O)2SO2 → 2 CH3AsO(ONa)2 \+ Na2SO4, followed by reduction of the disodium monomethylarsonate with sulfur dioxide: :CH3AsO(ONa)2 \+ SO2 → CH3AsO + Na2SO4, subsequently reacting the monomethylarsine oxide thus formed with hydrogen chloride to yield methyldichloroarsine: :CH3AsO + 2 HCl → CH3AsCl2 \+ H2O The As-Cl bonds in MD are susceptible toward nucleophilic attack.
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The chemical synthesis of gelsemine has been an active target of interest since the early 1990s, given its place among the alkaloids, and its complex structure (seven contiguous stereocenters and six rings). Its first racemic total synthesis was in 1994, by W.N. Speckamp's group, with a remarkable first yield of 0.83% (given the subsequent range, prior to 2014, of 0.02-1.2%).[primary source] Eight further total syntheses have been reported in the literature, including from the groups of A.P. Johnson in 1994, T. Fukuyama in 1996 and again in 2000, D.J. Hart in 1997, L.E. Overman in 1999, S.J. Danishefsky in 2002, and Y. Qin in 2012, with the latter Fukuyama group synthesis (31 steps, 0.86%) and the Qin group synthesis (25 steps, 1%) being asymmetric. A further asymmetric synthesis using an organocatalytic Diels–Alder approach from the F.G. Qiu and H. Zhai groups in China, reporting a remarkable 12 steps and a 5% yield, was reported in 2015.
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Use of a solid-supported polyamine to scavenge excess reagent Over the years, a variety of methods have been developed to refine the use of solid-phase organic synthesis in combinatorial chemistry, including efforts to increase the ease of synthesis and purification, as well as non-traditional methods to characterize intermediate products. Although the majority of the examples described here will employ heterogeneous reaction media in every reaction step, Booth and Hodges provide an early example of using solid-supported reagents only during the purification step of traditional solution-phase syntheses. In their view, solution-phase chemistry offers the advantages of avoiding attachment and cleavage reactions necessary to anchor and remove molecules to resins as well as eliminating the need to recreate solid-phase analogues of established solution-phase reactions. The single purification step at the end of a synthesis allows one or more impurities to be removed, assuming the chemical structure of the offending impurity is known.
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Today museology – as seen by ICOFOM – can be defined as "comprising all the efforts at theorization and critical thinking about the museum field". This vision, intentionally very broad, collects trends of thought that are often conflicting as they are linked to critical thinkers in different parts of the world, whether Benjamin Ives Gilman or Georges Brown Goode, John Cotton Dana or Joseph Veach Noble, and, more currently, Duncan F. Cameron, Neil Postman, Georges Henri Rivière, Zbyněk Stránský, André Desvallées, Stephen Weil or Roland Arpin. ICOFOM is harnessed to this work of research and synthesis, and strives to compile an inventory of the different ways to conceive of museums and museology and to generate, through these syntheses, the trends that emerge from the vast flux of change in the museum field. Within ICOFOM most working researchers teach at universities after having spent part of their career in a museum (or while continuing museum work at the same time).
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Raphael studied many natural products, especially of the type that were biologically active and which would provide a challenge for synthesis but might be the realistic target of a single PhD student's thesis. He and his students published syntheses of 2-deoxyribose, aaptamine, aphidicolin, apiose, arachidonic acid, arcyriaflavin B, baikiain, bullatenone, chrysanthemic acid, clovene, cordycepose, cuparene, erythrulose, exaltolide, farnesiferol C, geiparvarin, gibberone, histamine, linoleic acid, linolenic acid, lipoic acid, pseudomonic acid, pyrenophorin, Queen bee acid, shikimic acid, staurosporinone, strigol, steganacin, steganone, trichodermin and virantmicin. Raphael also investigated the composition of the wax coating of plant leaves, describing the hydrocarbons of which they are composed. In another intriguing publication in Nature, Raphael collaborated with David Rubio to identify components used in the surface treatment of the wood of stringed instruments made by Stradivarius in Cremona and showed that a version of these substances could be used to improve the tone of modern instruments.
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GAs are usually synthesized from the methylerythritol phosphate (MEP) pathway in higher plants. In this pathway, bioactive GA is produced from trans- geranylgeranyl diphosphate (GGDP). In the MEP pathway, three classes of enzymes are used to yield GA from GGDP: terpene syntheses (TPSs), cytochrome P450 monooxygenases (P450s), and 2-oxoglutarate–dependent dioxygenases (2ODDs). There are eight steps in the MEP pathway: # GGDP is converted to ent- copalyl diphosphate (ent-CPD) by ent-copalyl diphosphate synthase # etn-CDP is converted to ent-kaurene by ent-kaurene synthase # ent-kaurene is converted to ent-kaurenol by ent-kaurene oxidase (KO) # ent-kaurenol is converted to ent- kaurenal by KO # ent-kaurenal is converted to ent-kaurenoic acid by KO # ent- kaurenoic acid is converted to ent-7a-hydroxykaurenoic acid by ent-kaurene acid oxidase (KAO) # ent-7a-hydroxykaurenoic acid is converted to GA12-aldehyde by KAO # GA12-aldehyde is converted to GA12 by KAO. GA12 is processed to the bioactive GA4 by oxidations on C-20 and C-3, which is accomplished by 2 soluble ODDs: GA 20-oxidase and GA 3-oxidase.
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When Wallace Carothers arrived at DuPont in 1928 one of the tasks his group took on was the development of new synthetic fibers for textiles. At that time a number of natural polymers such as latex and cellulose were in common use, rayon as a semisynthetic from nitrated cellulose had recently been improved and begun upending the textile industries, and some fully synthetic polymers such as bakelite were also known and being used for certain applications, but the existing fully synthetic polymers could not be drawn into fibers and spun into thread, so great opportunity existed to manufacture thread and yarn from synthetic polymers to join or replace the existing fibers in the market (natural fibers such as cotton, wool, linen, and silk and artificial fiber in the various recently emerged types of rayon). The approach taken by Carothers' group was to adapt known syntheses that produced short-chain polymers to produce long-chain molecules. The first break was finding that bifunctional esterification could produce long molecule chains which today are known as aliphatic polyesters, but at that time were called superpolymers.
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Augustus in Egyptian style, on the temple of Kalabsha in Egyptian Nubia. In the Eastern provinces, cultural precedent ensured a rapid and geographically widespread dissemination of cult, extending as far as the Augustan military settlement at modern-day Najran.The caesareum at Najaran (in what is now south-west Saudi Arabia) was possibly later known as the "Kaaba of Najran": جواد علي, المفصل في تاريخ العرب قبل الإسلام (Jawad Ali, Al-Mufassal fi Tarikh Al-‘Arab Qabl Al- Islam; "Commentary on the History of the Arabs Before Islam"), Baghdad, 1955–1983 Considered as a whole, these provinces present the Empire's broadest and most complex syntheses of imperial and native cult, funded through private and public initiatives and ranging from the god-like honours due a living patron to what Harland (2003) interprets as privately funded communal mystery rites.Harland, 2003, 91–103, finds among these examples a privately funded local, traditional Graeco-Asian civil association offering cult to Demeter and the Emperor as a form of mystery cult: contra Price, 1986, 7–11, who believes that Emperors lacked the requisite fully divine status.
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"at the back of his mind, he may have intended eventually to restore the monarchy but it was a distant perspective", Preston 2011, p. 274 He cared little about dynastical debates and it seems compliance with his own vision and acceptance of his own leadership were the key criteria of choice. The dictator appreciated Carlism as its anti-democratic outlook to a large extent overlapped his own, but realized also that within the Spanish society it was a minority option and an Alfonsist candidate was more practicable, especially that Alfonsist sympathies prevailed among the top military.there is no monograph dealing with Franco’s views on monarchist restoration and the rivalry between the Carlists and the Alfonsists. Most popular English-language works presenting development of Franco’s ideas on the regime of Spain are respective chapters in two massive though definitely competivive syntheses, Payne 2011 and Preston 2011 Since heads of both branches, Don Juan and Don Javier, refused to be domesticated, caudillo concluded he should proceed on monarchist path as slowly as possible and keeping all options opened.
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He has also developed novel methodology for organic synthesis such as a modification of the Evans aldol reaction. In addition to his research and teaching accomplishments, Clayton Heathcock has contributed to the chemical community by serving as chairman of the Division of Organic Chemistry of the American Chemical Society (ACS), chairman of the National Institutes of Health Medicinal Chemistry Study Section, chairman of the Gordon Research Conference on Stereochemistry, chair of the Chemistry Division of the American Association for the Advancement of Science, and Editor-in Chief of the journals Organic Syntheses and the Journal of Organic Chemistry. Clayton Heathcock is the author of several hundred research papers and a coauthor of the popular college textbook Introduction to Organic Chemistry. Awards that Clayton Heathcock has received include Ernest Guenther Award (ACS) (1986); ACS Award for Creative Work in Organic Synthesis (1990); A.C. Cope Scholar (1990); Prelog Medal, ETH (1991); American Academy of Arts and Sciences (1991); National Academy of Sciences (1995); Centenary Medal, Royal Society of Chemistry (1996); H. C. Brown Award (ACS) (2002); Paul Gassman Award for Distinguished Service (ACS) (2004).
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Reyes-Valerio, De Bonampak al Templo Mayor, La historia del Azul Maya en Mesoamerica, Siglo XXI Editores, 1993. Reyes-Valerio's contributions were possibly due to his combined background of history and chemistry, through a thorough revision of primary texts (Sahagun, Hernandez, Jimenez, and others), microscopic analysis of the mural paintings and fourier transform infrared spectroscopy. After the formula for the production was published in the book De Bonampak al Templo Mayor: Historia del Azul Maya en Mesoamerica, many developments in the chemical analysis of the pigment occurred in collaborations between Reyes-Valerio and European scientists.notably, Giaccomo Chiari from the University of Torino, David Ajò from C.N.R. of Padua and Manuel Sanchez del Rio from ESRF in France A comprehensive study on the pigment which describes history, the experimental study techniques (diffraction studies, infrared spectroscopies, Raman amplification, optical spectroscopies, voltammetry, nuclear magnetic resonance, and computer modelling), the syntheses, properties and nature of Maya blue and the research in relation with the archaeological and historical contexts has been published in the journal Developments in Clay Science.
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Extensive surveys of structural variations have been conducted by pharmaceutical corporations, universities and independent researchers over the last century, from which some of the presently available research chemicals derive. One particularly notable researcher is Dr. Alexander Shulgin, who presented syntheses and pharmacological explorations of hundreds of substances in the books TiHKAL and PiHKAL (co-authored with Ann Shulgin), and has served as an expert witness for the defense in several court cases against manufacturers of psychoactive drugs. The majority of chemical suppliers sold research chemicals in bulk form as powder, not as pills, as selling in pill form would invalidate the claims that they were being sold for non-consumptive research. Active dosages vary widely from substance to substance, ranging from micrograms to hundreds of milligrams, but while it is critical for the end user to weigh doses with a precision scale, instead of guessing ("eyeballing"), many users did not do this and this led to many emergency room visits and several deaths, which were a prominent factor leading to the emergency scheduling of several substances and eventually Operation Web Tryp.
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The chemical properties of Ru3(CO)12 have been widely studied, and the cluster has been converted to hundreds of derivatives. High pressures of CO convert the cluster to the monomeric ruthenium pentacarbonyl, which reverts to the parent cluster upon standing. :Ru3(CO)12 \+ 3 CO 3 Ru(CO)5 Keq = 3.3 x 10−7 mol dm−3 at room temperature The instability of Ru(CO)5 contrasts with the robustness of the corresponding Fe(CO)5. The condensation of Ru(CO)5 into Ru3(CO)12 proceeds via initial, rate-limiting loss of CO to give the unstable, coordinatively unsaturated species Ru(CO)4. This tetracarbonyl binds Ru(CO)5, initiating the condensation.Hastings, W. R.; Roussel, M. R.; Baird, M. C. "Mechanism of the conversion of [Ru(CO)5] into [Ru3(CO)12]" Journal of the Chemical Society, Dalton Transactions, 1990, pages 203-205. Upon warming under a pressure of hydrogen, Ru3(CO)12 converts to the tetrahedral cluster H4Ru4(CO)12.Bruce, M. I.; Williams, M. L. "Dodecacarbonyl(tetrahydrido)tetraruthenium, Ru4(μ-H)4(CO)12" Inorganic Syntheses, 1989, volume 26, pages 262-63. .
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The situationist movement had its origins as a left wing tendency within Lettrism,Report on the Construction of Situations (1957) an artistic and literary movement led by the Romanian-born French poet and visual artist Isidore Isou, originating in 1940s Paris. The group was heavily influenced by the preceding avant-garde movements of Dadaism and Surrealism, seeking to apply critical theories based on these concepts to all areas of art and culture, most notably in poetry, film, painting and political theory. Among some of the concepts and artistic innovations developed by the Lettrists were the lettrie, a poem reflecting pure form yet devoid of all semantic content, new syntheses of writing and visual art identified as metagraphics and hypergraphics, as well as new creative techniques in filmmaking. Future situationist Guy Debord, who was at that time a significant figure in the Lettrist movement, helped develop these new film techniques, using them in his Lettrist film Howlings for Sade (1952) as well as later in his situationist film Society of the Spectacle (1972). By 1950, a much younger and more left-wing part of the Lettrist movement began to emerge.
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In the first of his four theological syntheses, Thomas composed a massive commentary on the Sentences titled Scriptum super libros Sententiarium (Commentary on the Sentences). Aside from his master's writings, he wrote De ente et essentia (On Being and Essence) for his fellow Dominicans in Paris. In the spring of 1256 Thomas was appointed regent master in theology at Paris and one of his first works upon assuming this office was Contra impugnantes Dei cultum et religionem (Against Those Who Assail the Worship of God and Religion), defending the mendicant orders, which had come under attack by William of Saint-Amour. During his tenure from 1256 to 1259, Thomas wrote numerous works, including: Questiones disputatae de veritate (Disputed Questions on Truth), a collection of twenty- nine disputed questions on aspects of faith and the human condition prepared for the public university debates he presided over on Lent and Advent; Quaestiones quodlibetales (Quodlibetal Questions), a collection of his responses to questions posed to him by the academic audience; and both Expositio super librum Boethii De trinitate (Commentary on Boethius's De trinitate) and Expositio super librum Boethii De hebdomadibus (Commentary on Boethius's De hebdomadibus), commentaries on the works of 6th-century Roman philosopher Boethius.
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While the combination of post-left opposition to capitalism and statism with right-wing support for ethnic and racial separatism makes its classification on the left–right political spectrum problematic, scholars who have examined national-anarchism consider it to be on the radical right. In his 2003 essay From. Slime Mould to Rhizome: An Introduction to the Groupuscular Right, Roger Griffin argued that national-anarchism is a segment of the groupuscular right which has evolved towards a "mazeway resynthesis" between "classic fascism, third positionism, neo-anarchism and new types of anti-systemic politics born of the anti-globalization movement", whose main ideological innovation is a stateless palingenetic ultranationalism. In his 2005 essay Co-opting the Counter Culture: Troy Southgate and the National Revolutionary Faction, described as a "case study of the National Revolutionary Faction (NRF)" which "provides a salutary example of fascism's cogent syncretic core and its ability to produce novel and pragmatic syntheses", Graham D. Macklin argued that the conservative revolutionary concept of the anarch provides sanction for the ideological shapeshifting and unrestrained syncretism of national- anarchism, allowing its adherents to assert they have transcended the dichotomy of conventional politics to embrace higher political forms that are "beyond left and right".
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The Schöllkopf method or Schöllkopf Bis-Lactim Amino Acid Synthesis is a method in organic chemistry for the asymmetric synthesis of chiral amino acids.Leo A. Paquette :Chiral Reagents for Asymmetric Synthesis, S.220-223, 2003, Wiley and Sons, Jan Bülle, Aloys Hüttermann : Das Basiswissen der organischen Chemie: Die wichtigsten organischen Reaktionen im Labor und in der Natur, S.310/311, 2000, Wiley-VCH, The method was established in 1981 by Ulrich Schöllkopf.Enantioselective Syntheses of (R)-Amino Acids Using L-Valine as Chiral Agent Angewandte Chemie International Edition in English Volume 20, Issue 9, Date: September 1981, Pages: 798-799 Ulrich Schöllkopf, Ulrich Groth, Chuanzheng Deng Enantioselective Synthesis of -Methyl--aminocarboxylic Acids by Alkylation of the Lactim Ether of cyclo-(L-Ala-L-Ala) Angewandte Chemie International Edition in English Volume 18, Issue 11, Date: November 1979, Pages: 863-864 Ulrich Schöllkopf, Wolfgang Hartwig, Ulrich Groth Asymmetric synthesis via heterocyclic intermediates - XXXIX1 : Asymmetric synthesis of (enantiomerically and diastereomerically virtually pure) methyl 2-amino-4,5-epoxy-3-hydroxy-alkanoates and methyl 2-amino-3-hydroxy-4,5-methylene-alkanoates by the bislactimether method Tetrahedron, Volume 44, Issue 17, 1988, Pages 5293-5305 Ulrich Schöllkopf, Thomas Tiller, Jürgen Bardenhagen In it glycine is a substrate, valine a chiral auxiliary and the reaction taking place an alkylation.
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Deep-sea hydrothermal vent or black smoker The deep sea vent, or alkaline hydrothermal vent, theory posits that life may have begun at submarine hydrothermal vents, Martin and Russell have suggested > that life evolved in structured iron monosulphide precipitates in a seepage > site hydrothermal mound at a redox, pH, and temperature gradient between > sulphide-rich hydrothermal fluid and iron(II)-containing waters of the > Hadean ocean floor. The naturally arising, three-dimensional > compartmentation observed within fossilized seepage-site metal sulphide > precipitates indicates that these inorganic compartments were the precursors > of cell walls and membranes found in free-living prokaryotes. The known > capability of FeS and NiS to catalyze the synthesis of the acetyl- > methylsulphide from carbon monoxide and methylsulphide, constituents of > hydrothermal fluid, indicates that pre-biotic syntheses occurred at the > inner surfaces of these metal-sulphide-walled compartments,... These form where hydrogen-rich fluids emerge from below the sea floor, as a result of serpentinization of ultra-mafic olivine with seawater and a pH interface with carbon dioxide-rich ocean water. The vents form a sustained chemical energy source derived from redox reactions, in which electron donors (molecular hydrogen) react with electron acceptors (carbon dioxide); see Iron–sulfur world theory.
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First prepared by Walter Hieber,Hieber, W.; Lagally, H. "Über Metallcarbonyle. XLV. Das Rhodium im System der Metallcarbonyle (Metal carbonyls. XLV. Rhodium in the system of metal carbonyls)" Zeitschrift für Anorganische und Allgemeine Chemie 1943, volume 251, pp. 96-113. it is typically prepared by treating hydrated rhodium trichloride with flowing carbon monoxide, according to this idealized redox equation: :2 RhCl3(H2O)3 \+ 6 CO → Rh2Cl2(CO)4 \+ 2 COCl2 \+ 6 H2O.McCleverty, J. A.; Wilkinson, G. "Dichlorotetracarbonyldirhodium (rhodium carbonyl chloride)" Inorganic Syntheses 1966, volume 8, pp. 211-14. The complex reacts with triphenylphosphine to give the bis(triphenylphosphine)rhodium carbonyl chloride: :Rh2Cl2(CO)4 \+ 4 PPh3 → 2 trans-RhCl(CO)(PPh3)2 \+ 2 CO With chloride salts, the dichloride anion forms: :Rh2Cl2(CO)4 \+ 2 Cl− → 2 cis-[RhCl2(CO)2]− With acetylacetone, rhodium carbonyl chloride reacts to give dicarbonyl(acetylacetonato)rhodium(I). The dimer reacts with a variety of Lewis bases (:B) to form adducts RhCl(CO)2:B. Its reaction with tetrahydrothiophene and the corresponding enthalpy are: :1/2 Rh2Cl2(CO)4 \+ :S(CH2)4 → RhCl(CO)2:S(CH2)4 ΔH = -31.8 kJ mol−1 This enthalpy corresponds to the enthalpy change for a reaction forming one mole of the product, RhCl(CO)2:S(CH2)4, from the acid dimer.
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