- Photochemical reductive homologation of hydrogen cyanide using sulfite and ferrocyanide
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Photoredox cycling during UV irradiation of ferrocyanide ([FeII(CN)6]4-) in the presence of stoichiometric sulfite (SO32-) is shown to be an extremely effective way to drive the reductive homologation
- Xu, Jianfeng,Ritson, Dougal J.,Ranjan, Sukrit,Todd, Zoe R.,Sasselov, Dimitar D.,Sutherland, John D.
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supporting information
p. 5566 - 5569
(2018/06/04)
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- Photoiodocarboxylation of Activated C=C Double Bonds with CO2 and Lithium Iodide
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The photolysis at 254 nm of lithium iodide and olefins 1 carrying an electron-withdrawing Z-substituent in CO2-saturated (1 bar) anhydrous acetonitrile at room temperature produces the atom efficient and transition metal-free photoiodocarboxylation of the C=C double bond. The reaction proceeds well for terminal olefins 1 to form the new C-I and C-C σ-bonds at the α and β-positions of the Z-substituent, respectively, and is strongly inhibited by polar protic solvents or additives. The experimental results suggest that the reaction channels through the radical anion [CO2?-] in acetonitrile, yet involves different intermediates in aqueous medium. The stabilizing ion-quadrupole and electron donor-acceptor interactions of CO2 with the iodide anion play a crucial role in the reaction course as they allow CO2 to penetrate the solvation shell of the anion in acetonitrile, but not in water. The reaction paths and the reactive intermediates involved under different conditions are discussed.
- Mello, Rossella,Arango-Daza, Juan Camilo,Varea, Teresa,González-Nú?ez, María Elena
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p. 13381 - 13394
(2018/11/20)
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- 2 - methyl malonic acid diester synthetic method of the compound
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The invention discloses a synthetic method of 2-diester methylmalonate compounds, and relates to the technical field of carboxylic ester preparation. The synthetic method comprises steps as follows: C, sulfonic acid 2-ethyl N-cyanoethanimideate IV and cyanide react under the action of a solvent and a catalyst, and 2-methyl malononitrile V is obtained; D, 2-methyl malononitrile V and ROH react under the action of the solvent and concentrated sulfuric acid, and products of 2-diester methylmalonate compounds I are obtained, wherein MCN is cyanide, M is Na or K, ROH is alkyl alcohol, alkenyl alcohol or a fluoride group containing alcohol, is benzyl alcohol or benzyl alkyl, halogen or nitro substituted benzyl alcohol, or is phenol or C1-C5 containing alkyl, halogen or nitro substituted phenol. The method is unique, the reaction conditions are mild, the reaction process is basically free of by-products, the yield is high, adopted raw materials have extensive sources, and acetaldehyde can be used as the raw material; the synthetic method is applicable to industrial production.
- -
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Paragraph 0033-0036
(2017/08/10)
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- Preparation method of 2-hydroxy acid ester
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The invention relates to a preparation method of 2-hydroxy acid ester and belongs to the technical field of organic synthesis. According to the preparation method of 2-hydroxy acid ester, 2-hydroxy alkyl cyanogens is taken as a raw material to be added to a reaction solution formed by hydrogen chloride, alcohol and water, and after reaction, 2-hydroxy acid ester is obtained. According to the preparation method of 2-hydroxy acid ester, use of a large amount of nonpolar solvent is not needed, and a target product can be obtained by a one-pot method, thus lowering production cost, improving production efficiency and the purify of the target product, and having energy-saving and environment-friendly effects.
- -
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Paragraph 0034-0035
(2017/04/11)
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- Method of manufacturing cyanohydrins
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Disclosed is a process for producing a cyanohydrin, the process comprising reacting a carbonyl compound with hydrocyanic acid in a buffer solution with a pH less than 7 to obtain the cyanohydrin.
- -
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Paragraph 0072; 0073
(2016/12/26)
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- Nickel-Catalyzed Asymmetric Reductive Cross-Coupling between Heteroaryl Iodides and α-Chloronitriles
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A Ni-catalyzed asymmetric reductive cross-coupling of heteroaryl iodides and α-chloronitriles has been developed. This method furnishes enantioenriched α,α-disubstituted nitriles from simple organohalide building blocks. The reaction tolerates a variety of heterocyclic coupling partners, including pyridines, pyrimidines, quinolines, thiophenes, and piperidines. The reaction proceeds under mild conditions at room temperature and precludes the need to pregenerate organometallic nucleophiles.
- Kadunce, Nathaniel T.,Reisman, Sarah E.
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supporting information
p. 10480 - 10483
(2015/09/28)
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- Hydration of alkenes and cycloalkenes in the presence of chromium and copper complexes
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Chromium and copper complexes catalyzed hydration of acyclic and cyclic olefins in the presence of carbon tetrachloride at 110-160 C (4-12 h) with formation of the corresponding alcohols.
- Khusnutdinov,Oshnyakova,Shchadneva
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p. 1428 - 1432
(2014/01/06)
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- Synthesis of aldehydic ribonucleotide and amino acid precursors by photoredox chemistry
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Light work: UV irradiation of a system formed by adding copper(I) cyanide to an aqueous solution of glycolonitrile, sodium phosphate, and hydrogen sulfide efficiently generates aldehyde precursors to the building blocks of RNA and proteins. Copyright
- Ritson, Dougal J.,Sutherland, John D.
-
supporting information
p. 5845 - 5847
(2013/07/11)
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- PROCESS FOR PRODUCTION OF CYANOHYDRIN COMPOUND, AND PROCESS FOR PRODUCTION OF ALPHA HYDROXYESTER COMPOUND
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A process according to the present invention for producing a cyanohydrin compound is a process for producing a cyanohydrin compound by performing a reaction between a carbonyl compound such as an aldehyde compound and hydrogen cyanide in the presence of a catalyst, a content of the carbonyl compound in a reaction system being not more than 50 mol % with respect to the cyanohydrin compound. Thus provided is a process for producing a cyanohydrin compound in good yield from an aldehyde compound and hydrogen cyanide.
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Page/Page column 6
(2010/10/19)
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- PROCESS FOR PRODUCTION OF CYANOHYDRIN COMPOUND, AND PROCESS FOR PRODUCTION OF ALPHA-HYDROXYESTER COMPOUND
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A process according to the present invention for producing a cyanohydrin compound is a process for producing a cyanohydrin compound by performing a reaction between a carbonyl compound such as an aldehyde compound and hydrogen cyanide in the presence of a catalyst, a content of the carbonyl compound in a reaction system being not more than 50 mol% with respect to the cyanohydrin compound. Thus provided is a process for producing a cyanohydrin compound in good yield from an aldehyde compound and hydrogen cyanide.
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Page/Page column 9
(2010/08/09)
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- PROCESS AND APPARATUS FOR PRODUCTION OF CYANOHYDRIN COMPOUND, AND PROCESS FOR PRODUCTION OF ALPHA -HYDROXYESTER COMPOUND
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A process according to the present invention for producing a cyanohydrin compound flow-reacts a carbonyl compound with hydrogen cyanide in the presence of a catalyst, and can therefore reduce the residence time. This makes it possible to reduce the period of time over which the resulting cyanohydrin compound is exposed to an unreacted portion of the carbonyl compound. As a result, the resulting cyanohydrin compound can be prevented from reacting with the unreacted portion. This makes it possible to produce the cyanohydrin compound in good yield. That is, the process according to the present invention for producing a cyanohydrin compound produces a cyanohydrin compound in good yield from a carbonyl compound and hydrogen cyanide.
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Page/Page column 16
(2010/08/09)
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- Tautomer selective photochemistry in 1-(tetrazol-5-yl)ethanol
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A combined matrix isolation FTIR and theoretical DFT/B3LYP/6-311++G(d,p) study of the molecular structure and photochemistry of 1-(tetrazol-5-yl)ethanol [1-TE] was performed. The potential energy surface landscapes of the 1H and 2H tautomers of the compound were investigated and the theoretical results were used to help characterize the conformational mixture existing in equilibrium in the gas phase prior to deposition of the matrices, as well as the conformers trapped in the latter. In the gas phase, at room temperature, the compound exists as a mixture of 12 conformers (five of the 1H tautomer and seven of the 2H tautomer). Upon deposition of the compound in an argon matrix at 10 K, only three main forms survive, because the low barriers for conformational isomerization allow extensive conformational cooling during deposition. Deposition of the matrix at 30 K led to further simplification of the conformational mixture with only one conformer of each tautomer of 1-TE surviving. These conformers correspond to the most stable forms of each tautomer, which bear different types of intramolecular H-bonds: 1H-I has an NH···O hydrogen bond, whereas 2H-I has an OH···N hydrogen bond. Upon irradiating with UV light (λ > 200 nm), a matrix containing both 1H-I and 2H-I forms, an unprecedented tautomer selective photochemistry was observed, with the 2H tautomeric form undergoing unimolecular decomposition to azide + hydroxypropanenitrile and the 1H-tautomer being photostable.
- Ismael,Cristiano,Fausto,Gomez-Zavaglia
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experimental part
p. 13076 - 13085
(2011/03/01)
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- Chiral solvating agents for cyanohydrins and carboxylic acids
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We have shown that a structure as simple as an ion pair of (R)- or (S)-mandelate and dimethylamminopyridinium ions possesses structural features that are sufficient for NMR enantiodiscrimination of cyanohydrins. Moreover, 1H NMR data of cyanohydrins of known configuration obtained in the presence of the mandelate-dimethylaminopyridinium ion pair point to the existence of a correlation between chemical shifts and absolute configuration of cyanohydrins. Mandelate-DMAPH+ ion pair and mandelonitrile form a 1:1 complex with an association constant of 338 M-1 (ΔG 0, -3.4 kcal/mol) for the (R)-mandelonitrile/(R)-mandelate-DMAPH + and 139 M-1 (ΔG0, -2.9 kcal/mol) for the (R)-mandelonitrile/(S)-mandelate-DMAPH+ complex. To understand the origin of enantiodiscrimination, the geometry optimization and energy minimization of the models of ternary complexes of (S)-mandelonitrile/(R)- mandelate/DMAPH+ and (S)-mandelonitrile/(S)-mandelate/DMAPH + complexes was performed using DFT methodology (B3LYP) with the 6-31+G(d) basis set in Gaussian 3.0. Further, analysis of optimized molecular model obtained from theoretical studies suggested that (i) DMAP may be replaced with other amines, (ii) the hydroxyl group of mandelic acid is not necessary for stabilization of ternary complex and may be replaced with other groups such as methyl, (iii) the ion pair should form a stable ternary complex with any hydrogen-bond donor, provided its OH bond is sufficiently polarized, and (iv) α-H of racemic mandelic acid should also get resolved with optically pure mandelonitrile. These inferences were experimentally verified, which not only validated the proposed model but also led to development of a new chiral solvating agent for determination of ee of carboxylic acids and absolute configuration of aryl but not alkyl carboxylic acids.
- Moon, Lomary S.,Pal, Mohan,Kasetti, Yoganjaneyulu,Bharatam, Prasad V.,Jolly, Ravinder S.
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body text
p. 5487 - 5498
(2010/11/05)
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- Nitrile hydratase and a method for producing amides
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An objective of the present invention is to provide a nitrile hydratase capable of producing 2-hydroxy-4-methylthiobutyroamide. The present invention provides a novel nitrile hydratase producing α-hydroxyamide using, α-hydroxnitrile as the substrate, and the encoding DNA thereof. The enzyme can be obtained from Rhodococcus sp. Further, the enzymatic activity of the enzyme can he maintained stably during the reaction. The present invention provides a method for producing amide compounds, the method comprising the step of reacting this enzyme to nitrile compounds. According to the present invention, from hydroxy nitrile compounds, corresponding amide compounds can be produced biochemically without reducing the enzyme activity of nitrile hydratase.
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- Method for producing organic compounds by substituting halogen atoms
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The invention pertains to a method in which a halogen atom of an organic compound is replaced with a group derived from a nucleophilic agent, at high yield and high efficiency, by the following method which includes a step of reacting the nucleophilic agent with an organic material having a halogen atom bonded to a carbon atom having four σ bonds, more specifically: a method for producing an organic compound having Q, the method including a step of reacting a compound represented by general formula (2) with an organic starting material having at least one halogen atom bonded to a carbon atom having four σ bonds so as to replace the halogen atom in the organic starting material with Q:MQa (wherein M represents an alkali metal atom, an alkali earth metal atom, or a rare earth metal atom; Q represents a moiety of an inorganic acid or an active hydrogen compound derived by eliminating a proton, wherein Q is a halogen atom different from the halogen atom in the organic starting material having the halogen atom bonded to the carbon atom having the four σ bonds; and a represents an integer of 1 to 3) in the presence of a compound represented by general formula (1) (wherein Z- represents an anion derived by eliminating a proton from an inorganic acid or an active hydrogen compound; R2 is the same or different; R2 each independently represent a C1-C10 hydrocarbon group or two R2 on the same nitrogen atom may be bonded with each other to form a ring with the nitrogen atom).
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- O-Protected 3-hydroxy-oxazolidin-2,4-diones: Novel precursors in the synthesis of α-hydroxyhydroxamic acids
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O-Protected 3-hydroxyoxazolidin-2,4-diones have been prepared in a novel one-pot reaction by subsequent treatment of cyanohydrins with 1,1′-carbonyldiimidazole and O-protected hydroxylamines followed by acidic hydrolysis of the intermediate 4-imino-oxazolidin-2-ones. Decarbonylation of O-protected 3-hydroxyoxazolidin-2,4-diones by catalytic amounts of sodium methoxide, lithium hydroxide, sodium carbonate and caesium carbonate in methanol afforded O-protected α-hydroxyhydroxamic acids in excellent yields. Their deprotection provided a series of novel α-hydroxyhydroxamic acids.
- Kurz, Thomas,Widyan, Khalid
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p. 2023 - 2027
(2007/10/03)
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- Nitrilase from rhodococcus rhodochrous ncimb 11216
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The invention relates to nucleic acid sequences which code for a polypeptide having nitrilase activity, to nucleic acid constructs comprising the nucleic acid sequences, and to vectors comprising the nucleic acid sequences or the nucleic acid constructs. The invention further relates to amino acid sequences which are encoded by the nucleic acid sequences, and to microorganisms comprising the nucleic acid sequences, the nucleic acid constructs or vectors comprising the nucleic acid sequences or the nucleic acid constructs. The invention additionally relates to an enzymatic process for preparing carboxylic acids from the corresponding nitrites.
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- P(MeNCH2CH2)3N: An efficient catalyst for the desilylation of tert- butyldimethylsilyl ethers
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tert-Butyldimethylsilyl (TBDMS) ethers of primary, secondary, and tertiary alcohols and phenolic TBDMS ethers are desilylated to their corresponding alcohols and phenols, respectively, in DMSO, at 80 °C, in 68- 94% yield in the presence of 0.2-0.4 equiv of P(MeNCH2CH2)3N. Using P(i- PrNCH2CH2)3N as the catalyst, 85-97% yields of desilylated alcohols were obtained from TBDMS ethers of 1-octanol, 2-phenoxyethanol, and racemic α- phenyl ethanol. These are the first examples of desilylations of silyl ethers catalyzed by nonionic bases. Both catalysts were much less effective for the desilylation of tert-butyldiphenylsilyl (TBDPS) ethers (22-45% yield) under the same conditions as used for TBDMS ethers. Possible pathways involving nucleophilic attack of the anion of the solvent molecule (generated by the catalyst) at the Si-O bond of silyl ether or a prior activation of the silyl ether by the catalyst via a P-Si interaction followed by nucleophilic attack of the solvent anion are proposed on the basis of 1H and 31P NMR experimental data.
- Yu, Zhengkun,Verkade, John G.
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p. 2065 - 2068
(2007/10/03)
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- Preparation process and purification process of cyclic ester
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A process for preparing a cyclic ester by reacting an α-hydroxycarboxylic acid or an α-hydroxycarboxyliclic acid ester with an orthoester. A process for purifying a cyclic ester by containing water and acid as impurities by adding an orthoester to a cyclic ester obtained by reaction of a reaction mixture including an α-hydrocarboxylic acid or an α-hydroxycarboxyliclic acid ester. According to the present invention, a high-purity cyclic ester containing small amounts of impurities such as water and an acid component can be provided.
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- Catalytic, asymmetric cyanohydrin synthesis mediated by lanthanide(III) chloride pybox complexes
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Complexes formed between lanthanide trichlorides and 2,6- bis(substituted-2-oxazolin-2-yl)pyridine (pybox) ligands are effective catalysts for the enantioselective addition of trimethylsilylcyanide (TMSCN) to a range of aldehydes.
- Aspinall, Helen C.,Greeves, Nicholas,Smith, Peter M.
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p. 1763 - 1766
(2007/10/03)
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- Process for preparing lactate
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A process for preparing a lactate which includes: (a) preparing lactonitrile from prussic acid and acetaldehyde, (b) hydrating the lactonitrile to form lactamide, (c) forming the desired lactate and formamide from lactamide and formate (or methanol and carbon monoxide), (d) separating and collecting components, having a lower boiling point than that of lactate from the reaction liquid in step (c), by distillation under specified conditions, and (e) dehydrating formamide from step (d) to form prussic acid and recycling the prussic acid to step (a). Heretofore, lactates had been manufactured by forming lactonitrile (cyanohydrin) from acetaldehyde and prussic acid, and then esterifying lactonitrile with a mineral acid or the like. However, in this conventional process, ammonium salts were formed as by-products in an amount equal to that of the lactate. According to the present invention, a lactate can be efficiently manufactured on a commercial scale without forming a large amount of the ammonium salts as by-products. In particular, the yield of the lactate can be increased by controlling the formation of 2-formyloxy propionate and also a dimer of a lactate.
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- Kinetics and mechanism of oxidation of glycine, alanine, and threonine by fluoride coordinated bismuth(V) in aqueous HClO4-HF medium
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The kinetics of oxidation of amino acids viz. glycine, alanine, and threonine with bismuth(V) in HClO4-HF medium have been studied. The kinetics of the oxidation of all these amino acids exhibit similar rate laws. The second-order rate constants were calculated to be 2.04 × 10-2 dm3 mol-1 and 2.72 × 10-2 dm3 mol-1 s-1 for glycine and alanine, respectively, at 35°C and 5.9 × 10-2 dm3 mol-1 s-1 for threonine at 25°C. All the possible reactive species of both bismuth(V) and amino acids have been discussed and a most probable kinetic model in each reaction has been envisaged.
- Devra,Jain,Sharma
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p. 577 - 586
(2007/10/03)
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- Facile Synthesis of 13C-2-Butenedinitrile and Regiospecifically Labeled 13C,15N-Pyridoxines
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Syntheses of -2-butenedinitrile in a one-pot process and pyridoxines regiospecifically multi-labeled with carbon-13 and nitrogen-15 are described.
- Hoshino, Jun-ichi,Yamamoto, Yukio,Hasegawa, Takeshi,Takahashi, Sho,Sawada, Seiji
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p. 1939 - 1941
(2007/10/02)
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- Investigation of the Structures of Some Natural Products from the Neem Tree
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Podocarpic acid (1) and totarol (2) have been converted into five diterpenoids reported to have been isolated from the Neem tree.The synthetic diterpenoids have been compared with the naturally occurring diterpenoids but only the structure of nimbidiol (23) has been confirmed.The structure for margosolone, which was reported as (19), has been revised to (20) after synthesis of both (19) and (20).
- Bendall, Justin G.,Cambie, Richard C.,Rutledge, Peter S.,Woodgate, Paul D.
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p. 1825 - 1844
(2007/10/02)
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- EFFICIENT RESOLUTION OF SECONDARY ALCOHOLS, CYANOHYDRINS, AND GLYCEROL ACETALS BY COMPLEXATION WITH THE HOST DERIVED FROM TARTARIC ACID
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Some title hydroxy compounds were resolved efficiently by complexation with the host compounds derived from tartaric acid.
- Toda, Fumio,Matsuda, Shotaro,Tanaka, Koichi
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p. 983 - 986
(2007/10/02)
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- Effect of Formaldehyde on Kinetics and Mechanism of Oxidation of Amino Acids by Bromamine-T in Perchloric Acid Medium
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The kinetics of oxidation of amino acids by bromamine-T (BAT) have been investigated both in the presence and absence of formaldehyde in perchloric acid medium.The reaction is first order in , zero order in both and and fractional order in in the presence of formaldehyde, and first order each in , and and inverse first order in in the absence of formaldehyde.Addition of p-toluenesulphonamide or variation in ionic strength of the medium does not have any significant effect on the rate, but the decrease in dielecrtic constant of the reaction medium decreases the rate.Activation parameters have been computed from the Arrhenius plots and mechanisms in conformity with the observed kinetics have been suggested and related rate laws deduced.The oxidation process in the presence of formaldehyde proceeds via two pathways.
- Gowda, B. Thimme,Rao, R. Vijayalakshmi
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- Asymmetric hydrolysis of 1-Cyanoalkyl Acetates
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Microorganisms that enantioselectively hydrolyze 1-cyanoalkyl acetates (aldehyde cyanohydrin) were screened.Candida tropicalis was found to be the best.The enzyme system of this strain catalyzed the enantioselective hydrolysis of (S)-isomers, leaving behind the (R)-acetates.The optical purities of recovered acetates were high as measured by 1H-NMR analysis in the presence of a chiral shift reagent.
- Ohta, Hiromichi,Hiraga, Satoshi,Miyamoto, Kenji,Tsuchihashi, Gen-ichi
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p. 3023 - 3028
(2007/10/02)
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- Chloride Ion-catalysed Oxidation of Arginine, Threonine, and Glutamic Acid by 1-Chlorobenzotriazole: a Kinetic and Mechanistic Study
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The kinetics of oxidation of arginine, threonine, and glutamic acid by 1-chlorobenzotriazole (CBT) were studied in HClO4 with Cl(1-) ion as a catalyst at 303 deg K.The results are compared with those obtained with chlorine water and HOCl as oxidant.The reactions followed identical kinetics, being first-order each in and and fractional order in . ions retard the reaction (inverse fractional order).The solvent isotope effect was studied.Variation of ionic strength and addition of the reaction product had no effect on the rate.A decrease in the dielectric constant of the medium increased the rate.Activation parameters were evaluated.A suitable mechanism consistent with the observed kinetics is proposed.
- Hiremath, Rajashekhar C.,Mayanna, Sanabaghatta M.,Venkatasubramanian, Nagaswami
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p. 1569 - 1574
(2007/10/02)
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- Mecanisme de la reaction de Bucherer-Bergs Comparaison avec l'hydratation basique des α-aminonitriles
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The Bucherer-Bergs reaction provides an important tool for the synthesis of α-aminoacids and is the basis of an industrial process for producing methionine.The key compound is the α-aminonitrile 1 which leads to partial decomposition in carbonate buffer as well as in weakly basic aqueous media and to the equilibrated formation of the basic intermediate α-carboxy-aminonitrile 2a.The parameters which control the stability of 2a are summarised.These equlibria are established through an initial fast step which is then followed by the formation of the hydantoin 5a.At a constant pH this formation is first order in α-carboxyaminonitrile 2a via a 5-imino-2-oxazolidinone 3a and an α-isocyanatamide 4a.A comparison of the reactivity of 1 with that of the N-alkylated compouds 7 shows that the rate determining step of the hydantoin formation is the cyclisation of 2a at pH9.But at higher pH, the reaction is controlled by the fast partitioning of the cyclic intermediate 3a between the α-carboxyaminonitrile 2a and the isocyanatamide 4a.This study permits the direct comparison between two mechanism for the synthesis of the racemic α-aminoacids: the Bucherer-Bergs way and the catalytic hydratation of α-aminonitriles.It is clear that carbonic anhydre can be considered as a special carbonyl compound with respect to its reactivity towards α-aminonitriles.
- Taillades, Jacques,Rousset, Alain,Lasperas, Monique,Commeyras, Auguste
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p. 650 - 658
(2007/10/02)
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- Process for preparing monoesters and diesters of N-alkyl substituted amino methyl phosphonic acid
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A process for preparing monoesters and diesters of N-alkyl substituted amino methyl phosphonic acid which are useful as herbicides.
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- Systemes de Strecker et apparentes XV. Comportement d'α-alcoylaminonitriles en presence de CS2 et de CO2
-
Dans le cadre de l'etude de la reaction de Bucherer-Bergs (transformation, en solution aqueuse, d'un compose carbonyle en acide α-amine correspondant via l'α-aminonitrile puis l'imidazolidinedione-2,4) le comportement d'α-alcoylaminonitriles en presence de CS2 est examine et elargi au systeme α-alcoylaminonitriles/CO2 en solution aqueuse.En presence de CS2, l'α-aminonitrile conduit a la formation equilibree d'imino-5 thiazolidine thione-2.Son evolution ulterieure vers l'imidazolidine dithione-2,4 alcoyle-1 est bloquee par la substitution sur l'azote 3.Par contre, nous avons mis en evidence la formation inattendue de l'imidazolidine dithione-2,4 non substituee.En solution aqueuse et en presence de CO2, l'imino-5 oxazolidinone-2 que nous n'avons pas decelee doit etre en equilibre tres defavorise avec l'α-carboxyaminonitrile.Les seules reactions observees sont l'hydratation autocatalitique de l'α-aminonitrile et sa decomposition en hydroxy-2 propionitrile et en α-aminodinitrile.
- Rousset, A.,Lasperas, M.,Taillades, J.,Commeyras, A.
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p. 209 - 216
(2007/10/02)
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- Alkylphosphonate monoesters of N-phosphonomethylglycinate as herbicides
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Alkylphosphonate monoesters of N-phosphonomethylglycine are disclosed which are useful as herbicides. This invention further relates to herbicidal compositions containing such alkylphosphonate monoesters of N-phosphonomethylglycine and to herbicidal methods employing such compounds and compositions.
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- Chloraminometric Reactions: Kinetics and Mechanisms of Oxidations of Amino-acids by Sodium N-Chlorotoluene-p-sulphonamide in Acid and Alkaline Media
-
Available data on the kinetics of oxidations of amino-acids by sodium N-chloro toluene-p-sulphonamide (chloramine T) in acid and alkaline media have been critically examined.General mechanisms have been proposed for both acid and alkaline medium oxidations.The oxidation process in acid media has been shown to proceed via two paths, one involving the direct interaction of N-chlorotoluene-p-sulphonamide (RNHCl) with the neutral amino-acid in a slow step leading to the formation of the monochloroamino-acid which subsequently interacts with another molecule of RNHCl, in a fast step, to give the NN-dichloroamino-acid which in turn undergoes molecular rearrangement and elimination to yield the products, and the other involving the interaction of Cl2 or H2OCl(1+), produced from the disproportionation of RNHCl in the presence or absence of Cl(1-), with the substrate to give the products.In the alkaline medium mechanisms involving the interaction of RNHCl, HOCl, RNCl(1-), and OCl(1-) with the substrate are proposed.The mechanisms proposed and the derived rate lows are consistent with the observed kinetics.The rate constants predicted by the derived rate laws, as the concentrations of substrate and Cl(1-) ion change, are in excellent agreement with the observed rate constants thus further verifying the rate laws and hence the proposed mechanisms.
- Gowda, Basavalinganadoddy Thimme,Mahadevappa, Darndinasivara S.
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p. 323 - 334
(2007/10/02)
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- Metabolites of the Higher Fungi. Part 19. Serpenone, 3-Methoxy-4-methyl-5-prop-1-enylfuran-2(5H)-one, a new γ-Butyrolactone from the Fungus Hypoxylon serpens (Barrons strain) (Persoon ex Fries)Kickx
-
Culture solutions of the fungus Hypoxylon serpens (Barrons strain) contain a new butyrolactone as the major metabolite, which has been identified as 3-methoxy-4-methyl-5-prop-1-enylfuran-2(5H)-one (2),and small quantities of the reduced analogue, 3-methoxy-4-methyl-5-propylfuran-2(5H)-one (3); the structures have been established by synthesis of compound (3).A new rapid synthesis of the isomeric 4-methoxy-3,5-disubstituted analogues is described and the two groups of compounds are compared spectroscopically.
- Anderson, John R.,Edwards, Raymond L.,Whalley, Anthony J. S.
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p. 215 - 222
(2007/10/02)
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- Kinetics and Mechanism of Oxidation of L-Threonine in Acid Media by Sodium N-Chloro-p-toluenesulfonamide
-
Kinetics of oxidation of L-threonine in the presence of HCl, HClO4, and H2SO4 by chloramine-T (CAT) has been investigated at 35 deg C.The reactions follow identical kinetics in all acids, being first order in CAT, fractional order in substrate and Cl- ion, and of an inverse fractional order in +>.Variation of ionic strength and addition of the reaction product, p-toluenesulfonamide, or the ions SO42- and ClO4- had no effect on the rate.Decrease of dielectric constant of the medium by adding methanol decreased the rate.The solvent isotope effect was studied by using heavy water.The reactions were studied at different temperatures, and activation parameters have been computed.Mechanisms proposed and the derived rate laws are consistent with the observed kinetics.The rate constants predicted by the derived rate laws, as the concentrations of H+ ion, substrate, and Cl- ion change, are in excellent agreement with the observed rate constants, thus further justifying these rate laws and hence the proposed mechanistic schemes.
- Mahadevappa, D. S.,Rangappa, K. S.,Gowda, N. M. M.,Gowda, B. Thimme
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p. 3651 - 3658
(2007/10/02)
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- SYSTEMES DE STRECKER ET APPARENTES - XI FORMATION ET STABILITE DE L'α-CARBOXYAMINONITRILE. INTERMEDIAIRE ESSENTIEL DANS LA SYNTHESE DES HYDANTOINES SELON BUCHERER-BERGS
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The determination of the structure of the intermediate in the Bucherer-Bergs reaction (the transformation in aqueous solution of an aldehyde into the corresponding amino-acid via the hydantoin) showed that this reaction involved the formation of α-aminonitrile carbamate.The slow formation of the carbonic anhydride from the carbonate buffer limited the formation of that main intermediate which was in equilibrium with the α-aminonitrile.The variation of the stability of the carbamate vs pH is mainly determined by the concentration of CO2 dissolved in the mixture, but also by the equilibrated formation of products formed by the degradation of α-aminonitrile, i.e. the aminodinitrile and the cyanohydrin.
- Rousset, A.,Lasperas, M.,Taillades, J.,Commeyras, A.
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p. 2649 - 2661
(2007/10/02)
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- Ureidonitriles useful as antihypertensives
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Ureidonitriles, such as N-(1-cyano-1-methylethyl)-N'-(1,1-dimethylethyl)urea with antihypertensive activity in warm-blooded animals.
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