5694-02-0Relevant articles and documents
Exploring the scope of an α/β-aminomutase for the amination of cinnamate epoxides to arylserines and arylisoserines
Shee, Prakash K.,Ratnayake, Nishanka Dilini,Walter, Tyler,Goethe, Olivia,Onyeozili, Edith Ndubuaku,Walker, Kevin D.
, p. 7418 - 7430 (2019/08/20)
Biocatalytic process-development continues to advance toward discovering alternative transformation reactions to synthesize fine chemicals. Here, a 5-methylidene-3,5-dihydro-4H-imidazol-4-one (MIO)-dependent phenylalanine aminomutase from Taxus canadensis (TcPAM) was repurposed to irreversibly biocatalyze an intermolecular amine transfer reaction that converted ring-substituted trans-cinnamate epoxide racemates to their corresponding arylserines. From among 12 substrates, the aminomutase ring-opened 3′-Cl-cinnamate epoxide to 3′-Cl-phenylserine 140 times faster than it opened the 4′-Cl-isomer, which was turned over slowest among all epoxides tested. GC/MS analysis of chiral auxiliary derivatives of the biocatalyzed phenylserine analogues showed that the TcPAM-transamination reaction opened the epoxides enantio- A nd diastereoselectively. Each product mixture contained (2S)+(2R)-anti (erythro) and (2S)+(2R)-syn (threo) pairs with the anti-isomers predominating (-90:10 dr). Integrating the vicinal proton signals in the 1H NMR spectrum of the enzyme-catalyzed phenylserines and calculating the chemical shift difference (?"?) between the anti and syn proton signals confirmed the diastereomeric ratios and relative stereochemistries. Application of a (2S)-threonine aldolase from E. coli further established the absolute stereochemistry of the chiral derivatives of the diastereomeric enzymatically derived products. The 2R:2S ratio for the biocatalyzed anti-isomers was highest (88:12) for 3′-NO2-phenylserine and lowest (66:34) for 4′-F-phenylserine. This showed that the stereospecificity of TcPAM is in part directed by the substituent-type on the cinnamate epoxide analogue. The catalyst also converted each cinnamate epoxide analogue to its corresponding isoserine, highlighting a biocatalytic route to arylisoserines, which play a key role in building the pharmacophore seen in anticancer and protease inhibitor drugs.
1-Acetyl-5-phenyl-1H-pyrrol-3-ylacetate: An aldose reductase inhibitor for the treatment of diabetic nephropathy
Xiu, Zhi-Ming,Wang, Li-Ping,Fu, Jun,Xu, Jia,Liu, Li
, p. 4482 - 4487 (2017/09/12)
Diabetic nephropathy (DN) is the most common and serious complication in diabetes mellitus, but the efficacy of available strategies for preventing this disorder remains poor. The aim of this study was to investigate the possible beneficial effects of 1-a
Oxidation of some unsaturated acids by tetrakis (pyridine) silver dichromate: A kinetic and mechanistic study
Choudhary,Yajurvedi,Kumbhani,Shastri,Sharma, Vinita
scheme or table, p. 832 - 836 (2010/06/12)
The oxidation of a few unsaturated acids viz. maleic, fumaric, crotonic and cinnamic acids by tetrakis (pyridine) silver dichromate (TPSD) in dimethylsulphoxide (DMSO) leads to the formation of corresponding epoxide. The reaction is of first order with respect to TPSD and the acid. The reaction is catalysed by hydrogen ions. The hydrogen-ion dependence has the form : k obs = a + b [H+]. The oxidation of these acids was studied in nineteen different organic solvents. The solvent effect was analyzed by Kamlet's and Swain's multiparametric equations. Solvent effect indicated the importance of the cation-solvating power of the solvent. A mechanism involving a three-centre transition state has been postulated.
Epoxidation and oxidation reactions using divinyl benzene crosslinked polystyrene supported t-butyl hydroperoxide
Sheela,Sreekumar
, p. 943 - 950 (2007/10/03)
Divinyl benzene (DVB) crosslinked polystyrene supported t-butyl hydroperoxide resin has been prepared and employed in the epoxidation of olefins and oxidation of alcohols. The reagent is found to be efficient as the low molecular weight t-butyl hydroperoxide. Presence of catalyst enhanced the reaction efficiency remarkably. Influence of various reaction parameters such as solvent, temperature and molar excess of the reagent on the reactivity of the polymeric reagent is also being investigated.
Kinetics and mechanism of the oxidation of some unsaturated acids by quinolinium bromochromate
Vyas, Shweta,Sharma, Pradeep K.
, p. 820 - 823 (2007/10/03)
The oxidation of maleic, fumaric, crotonic and cinnamic acids by quinolinium bromochromate (QBC) in dimethylsulphoxide (DMSO) leads to the formation of corresponding epoxide. The reaction is of first order with respect to QBC and the acid. The reaction is catalysed by hydrogen ions. The hydrogen-ion dependence has the form: kobs = a + b [H+]. The oxidation of these acids was studied in nineteen different organic solvents. The solvent effect was analyzed by Kamlet's and Swain's multiparametric equations. Solvent effect indicated the importance of the cation-solvating power of the solvent. A mechanism involving a three-centre transition state has been postulated.
Direct epoxidation of unprotected olefinic carboxylic acids using HOF-CH3CN
Rozen, Shlomo,Bareket, Yifat,Dayan, Sharon
, p. 531 - 534 (2007/10/02)
The reaction of HOF·CH3CN complex, made directly by passing fluorine through aqueous acetonitrile, with double bond containing unprotected carboxylic acids and alcohols results in fast and almost quantitative epoxidation.
A CONVENIENT SYNTHESIS OF OPTICALLY ACTIVE 1H-AZIRIDINE-2-CARBOXYLIC ACIDS (ESTERS).
Legters, J.,Thijs, L.,Zwanenburg, B.
, p. 4881 - 4884 (2007/10/02)
Optically active glycidic esters, prepared from allylic alcohols employing the Sharpless epoxidation, were treated with sodium azide.In a subsequent reaction with PPh3 the azido alcohols thus obtained were converted into aziridine-2-carboxylic esters of high optical purity in good yields.
CATALYTIC OXIDATION OF ALDEHYDES TO CARBOXYLIC ACIDS WITH HYDROGEN PEROXYDE AS OXIDANT
Choi, Joong-Kwon,Chang, Young-Kil,Hong, Sung Yeap
, p. 1967 - 1970 (2007/10/02)
Alkyl and aryl aldehydes were catalytically oxidized to carboxylic acids in high yields with hydrogen peroxide as oxidant using benseneseleninic acid as catalyst.
