- Oxygen-to-Oxygen Silyl Migration of α-Siloxy Sulfoxides and Oxidation-Triggered Allicin Formation
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Oxidation of α-siloxy thioethers leads to the formation of the corresponding sulfoxides as unstable intermediates, which undergo an intramolecular oxygen-to-oxygen silyl migration to break the C-S linkage. This process produces silyl protected sulfenic acids and subsequently thiosulfinates. It was used to develop oxidation-triggered allicin donors.
- Kelly, Shane S.,Shen, Tun-Li,Xian, Ming
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supporting information
p. 3741 - 3745
(2021/05/10)
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- Method for industrially synthesizing methyl 2-hydroxyvalerate by using acrylonitrile byproduct hydrocyanic acid
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The invention discloses a method for industrially synthesizing methyl 2-hydroxyvalerate by using acrylonitrile byproduct hydrocyanic acid, and relates to the technical field of chemical engineering. The acrylonitrile byproduct hydrocyanic acid is used as a starting raw material, and methyl 2-hydroxyvalerate is prepared through synthesis, hydrolytic esterification, neutralization, separation, rectification and the like. The comprehensive development and utilization approach of acrylonitrile byproduct hydrocyanic acid is expanded, so that acrylonitrile byproduct hydrocyanic acid is utilized more reasonably and efficiently, and the overall production and operation economic benefits of an acrylonitrile device are improved.
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Paragraph 0014-0022
(2021/05/05)
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- Enantioselective Synthesis of α-Thiocarboxylic Acids by Nitrilase Biocatalysed Dynamic Kinetic Resolution of α-Thionitriles
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The enantioselective synthesis of α-thiocarboxylic acids by biocatalytic dynamic kinetic resolution (DKR) of nitrile precursors exploiting nitrilase enzymes is described. A panel of 35 nitrilase biocatalysts were screened and enzymes Nit27 and Nit34 were found to catalyse the DKR of racemic α-thionitriles under mild conditions, affording the corresponding carboxylic acids with high conversions and good-to-excellent ee. The ammonia produced in situ during the biocatalytic transformation favours the racemization of the nitrile enantiomers and, in turn, the DKR without the need of any external additive base.
- Lauder, Kate,Anselmi, Silvia,Finnigan, James D.,Qi, Yuyin,Charnock, Simon J.,Castagnolo, Daniele
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supporting information
p. 10422 - 10426
(2020/07/24)
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- Ester Synthesis in Water: Mycobacterium smegmatis Acyl Transferase for Kinetic Resolutions
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The acyl transferase from Mycobacterium smegmatis (MsAcT) catalyses transesterification reactions in aqueous media because of its hydrophobic active site. Aliphatic cyanohydrin and alkyne esters can be synthesised in water with excellent and strikingly opposite enantioselectivity [(R);E>37 and (S);E>100, respectively]. When using this enzyme, the undesired hydrolysis of the acyl donor is an important factor to take into account. Finally, the choice of acyl donor can significantly influence the obtained enantiomeric excesses. (Figure presented.).
- de Leeuw, Nicolas,Torrelo, Guzman,Bisterfeld, Carolin,Resch, Verena,Mestrom, Luuk,Straulino, Emanuele,van der Weel, Laura,Hanefeld, Ulf
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p. 242 - 249
(2017/11/16)
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- A method for synthesis of 1, 2 - pentanediol (by machine translation)
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The invention relates to the field of organic synthetic technology, in particular to a 1, 2 - pentanediol synthetic method, comprises the following steps: (1) heating the raw material-butyraldehyde, adjusting the pH after adding the hydrocyanic acid, obtained by the reaction of 2 - hydroxy pentanonitrile; (2) taking step (1) in 2 - hydroxy pentanonitrile, adding an alcohol as a solvent to stir and mix, add water to stir and mix, hydrogen chloride gas, in 5 °C the following reaction under the condition for a period of time, to continue the reaction temperature, after the reaction product after the neutralization reaction, centrifugal separation, obtained after the distillation is 2 - hydroxy valeric acid ester compound; (3) heating the step (2) in 2 - hydroxy valeric acid ester compound, under the effects of catalyst after hydrogenation reaction to obtain the 1, 2 - pentanediol. Using the synthesis method of the invention, the 1, 2 - pentanediol yield, and reduces the production cost. (by machine translation)
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Paragraph 0024; 0029; 0034; 0039; 0042; 0044; 0050
(2018/10/19)
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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 0037-0038
(2017/04/11)
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- High-Throughput Preparation of Optically Active Cyanohydrins Mediated by Lipases
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Cyanohydrins are versatile compounds with high applicability in organic synthesis; they are used as starting materials for the synthesis of other chemical targets with high industrial added value. Lipase-mediated kinetic resolution reactions are a promising route for the synthesis of optically active cyanohydrins. These reactions can be carried out through the acylation of cyanohydrins or the deacylation of cyanohydrin esters, with different biocatalysts and under different reaction conditions. Unfortunately, depending on the substrate structure, long reaction times can be required to achieve suitable enantiomeric excesses. In this context, we present a high-throughput protocol for the production of optically active cyanohydrins in continuous-flow mode. The products were obtained with moderate to good enantioselectivity (E values from 8 up to >200) and with productivity values from 2.4 to 8.7 times higher in continuous-flow mode than in batch mode. Moreover, the reaction times were reduced from hours in batch mode to minutes in continuous-flow mode.
- Thomas, Juliana Christina,Aggio, Bruno Bernardi,Marques de Oliveira, Alfredo Ricardo,Piovan, Leandro
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supporting information
p. 5964 - 5970
(2016/12/26)
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- Catalytic Promiscuity of Ancestral Esterases and Hydroxynitrile Lyases
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Catalytic promiscuity is a useful, but accidental, enzyme property, so finding catalytically promiscuous enzymes in nature is inefficient. Some ancestral enzymes were branch points in the evolution of new enzymes and are hypothesized to have been promiscuous. To test the hypothesis that ancestral enzymes were more promiscuous than their modern descendants, we reconstructed ancestral enzymes at four branch points in the divergence hydroxynitrile lyases (HNL's) from esterases ~100 million years ago. Both enzyme types are α/β-hydrolase-fold enzymes and have the same catalytic triad, but differ in reaction type and mechanism. Esterases catalyze hydrolysis via an acyl enzyme intermediate, while lyases catalyze an elimination without an intermediate. Screening ancestral enzymes and their modern descendants with six esterase substrates and six lyase substrates found higher catalytic promiscuity among the ancestral enzymes (P 0.01). Ancestral esterases were more likely to catalyze a lyase reaction than modern esterases, and the ancestral HNL was more likely to catalyze ester hydrolysis than modern HNL's. One ancestral enzyme (HNL1) along the path from esterase to hydroxynitrile lyases was especially promiscuous and catalyzed both hydrolysis and lyase reactions with many substrates. A broader screen tested mechanistically related reactions that were not selected for by evolution: decarboxylation, Michael addition, γ-lactam hydrolysis and 1,5-diketone hydrolysis. The ancestral enzymes were more promiscuous than their modern descendants (P = 0.04). Thus, these reconstructed ancestral enzymes are catalytically promiscuous, but HNL1 is especially so.
- Devamani, Titu,Rauwerdink, Alissa M.,Lunzer, Mark,Jones, Bryan J.,Mooney, Joanna L.,Tan, Maxilmilien Alaric O.,Zhang, Zhi-Jun,Xu, Jian-He,Dean, Antony M.,Kazlauskas, Romas J.
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supporting information
p. 1046 - 1056
(2016/02/05)
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- A simple separation method for (S)-hydroxynitrile lyase from cassava and its application in asymmetric cyanohydrination
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Using an acetone precipitation method, crude (S)-hydroxynitrile lyase [(S)-MeHNL] was separated from Munihot esculenta (cassava) leaves, and used directly as biocatalyst to catalyze asymmetric cyanohydrination and produce cyanohydrins with enantiomeric purities (≥90% ee) significantly greater than those previously reported. The use of a water/i-Pr2O system with an enzyme, NaCN, and appropriate amounts of acetic acid is crucial in improving the stereoselectivity of cyanohydrin formation by minimizing the non-enzymatic reaction and the racemization of the chiral products. The proposed isolation method for crude (S)-MeHNL has a high value because of its simplicity, and low cost as well as the high activity of the crude (S)-MeHNL.
- Zheng, Zubiao,Zi, Yan,Li, Zhongzhou,Zou, Xinzhuo
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p. 434 - 439
(2013/06/27)
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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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- A dream combination for catalysis: Highly reactive and recyclable scandium(iii) triflate-catalyzed cyanosilylations of carbonyl compounds in an ionic liquid
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The catalytic activity of lanthanide triflates, particularly scandium triflate, increased dramatically in [bmim][SbF6], allowing the cyanosilylation of a variety of aldehydes and ketones with a turnover frequency up to 48000 mol h-1 and a total turnover number of 100000.
- Park, Boyoung Y.,Ryu, Ka Yeon,Park, Jung Hwan,Lee, Sang-Gi
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experimental part
p. 946 - 948
(2010/04/23)
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- Synthesis of 5,5′-dialkyl-6,6′-dichloro-2, 2′-bipyridines
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5,5′-Dialkyl-6,6′-dichloro-2,2′-bipyridines were synthesized starting from 3-substituted 2-chloro-6-iodopyridines using Pd-catalyzed coupling conditions. 6-Alkyl-3,5-dichloro-2H-1,4-oxazin-2-ones were excellent precursors for the synthesis of these functionalized 2-iodo-6-chloropyridines. Copyright Taylor & Francis Group, LLC.
- Chandia,Canales,Azocar,Vanlaer,Pawar,De Borggraeve,Costamagna,Dehaen
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experimental part
p. 927 - 939
(2009/08/08)
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- Synthesis of aliphatic (S)-α-hydroxycarboxylic amides using a one-pot bienzymatic cascade of immobilised oxynitrilase and nitrile hydratase
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A one-pot bienzymatic cascade combining a hydroxynitrile lyase (Manihot esculenta, E.C. 4.1.2.10) and a nitrile hydratase (Nitriliruptor alkaliphilus, E.C. 4.2.1.84) for the synthesis of enantiopure aliphatic α- hydroxycarboxylic amides from aldehydes is described. Both enzymes were immobilised as cross-linked enzyme aggregates (CLEAs). Stability tests show that the nitrile hydratase CLEAs are sensitive to water-immiscible organic solvents as well as to aldehydes and hydrogen cyanide (HCN), but are remarkably stable and show useful activity in acidic aqueous environments of pH 4-5. The cascade reactions are consequently carried out by using a portionwise feed of HCN and moderate concentrations of aldehyde in acidic aqueous buffer to suppress the uncatalysed hydrocyanation background reaction. After optimisation, this method was used to synthesise five different kinds of aliphatic α- hydroxycarboxylic amides from the corresponding aldehydes with good yields and with enantiomeric purities comparable to those obtained for the α-hydroxynitriles in the microaqueous hydrocyanation using hydroxynitrile lyase and an excess of HCN.
- Van Pelt, Sander,Van Rantwijk, Fred,Sheldon, Roger A.
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experimental part
p. 397 - 404
(2009/12/01)
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- PROCESS FOR PRODUCTION OF 2-HYDROXY ESTERS
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The invention provides an easy and simple process for the production of 2-hydroxy esters from cyanohydrins, specifically, a process for the production of 2-hydroxy esters represented by the general formula (1) (exclusive of ethyl 2-hydroxy-4-phenylbutyrate), characterized by introducing an acid into a mixture comprising a cyanohydrin represented by the general formula (2), an alcohol, an organic solvent and water: [Chemical formula 1] R1 -CH(OH)-COOR2 (1) R1 -CH(OH)(CN) (2) wherein R1 is hydrogen, a substituted or unsubstituted aliphatic hydrocarbon group which has 1 to 12 carbon atoms and may contain oxygen, sulfur, or nitrogen, a substituted or unsubstituted alicyclic hydrocarbon group which has 3 to 12 carbon atoms and may contain oxygen, sulfur, or nitrogen, or a substituted or unsubstituted aryl or aralkyl group which has 3 to 14 carbon atoms and may contain oxygen, sulfur, or nitrogen; and R2 is alkyl which has 1 to 12 carbon atoms and may contain oxygen, sulfur, or nitrogen.
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Page/Page column 11
(2010/11/30)
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- PROCESS FOR PREPARING 1,2-DIOLS FROM CARBONYL COMPOUNDS
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1,2-diols can be obtained in good yields and in very high purity by a process of a) reacting a carbonyl compound of the general formula (I) with hydrocyanic acid to give the corresponding cyanohydrin, wherein R1 and R2 are each independently H, an optionally substituted straight-chain or branched C1-C18-alkyl radical, or an optionally substituted phenyl or C5-C6-cycloalkyl radical, b) subjecting the cyanohydrin obtained in process step a) to an acidic hydrolysis, and c) catalytically hydrogenating the 2-hydroxycarboxylic acid obtained from process step b) in the presence of a noble metal catalyst comprising ruthenium and rhenium.
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Page/Page column 3
(2008/06/13)
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- A new (R)-hydroxynitrile lyase from Prunus mume: Asymmetric synthesis of cyanohydrins
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A new hydroxynitrile lyase (HNL) was isolated from the seed of Japanese apricot (Prunus mume). The enzyme has similar properties with HNL isolated from other Prunus species and is FAD containing enzyme. It accepts a large number of unnatural substrates (benzaldehyde and its variant) for the addition of HCN to produce the corresponding cyanohydrins in excellent optical and chemical yields. A new HPLC based enantioselective assay technique was developed for the enzyme, which promotes the addition of KCN to benzaldehyde in a buffered solution (pH=4.5).
- Nanda, Samik,Kato, Yasuo,Asano, Yasuhisa
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p. 10908 - 10916
(2007/10/03)
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- Process for preparation of cyanohydrins
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This invention relates to the discovery that high yields of excellent quality cyanohydrins can be prepared by reacting certain carbonyl compounds in a solution of metallic cyanide and hydrochloric acid.
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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
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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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