communis) have been applied to catalyze the asymmetricsynthesis of (R)‐4‐methylsulfanylmandelonitrile, a key building block of thiamphenicol and florfenicol. Here, four hydroxynitrile lyase (HNL) isozymes from Badamu were cloned and heterologously expressed in Pichia pastoris. The biochemical properties and catalytic performances of these isozymes were comprehensively explored to evaluate their efficiency
Enzymatic kinetic resolution of racemic cyanohydrins via enantioselective acylation
作者:Qing Xu、Yongli Xie、Xiaohong Geng、Peiran Chen
DOI:10.1016/j.tet.2009.11.074
日期:2010.1
Enzymatickineticresolution of a series of aromatic and aliphatic cyanohydrins in organic media has been investigated. The behavior of potential lipases, molecular sieves, acyl reagent, reaction temperature, and organic solvents on the kineticresolution was studied. The influence of substrate structure, steric, and electronic nature and position of the aryl substituent on the enantioselectivity was
undertaken. When Lewis acid catalysis is dominant, a significantly positive reaction constant is observed, whereas reactions dominated by Lewisbasecatalysis give much smaller reaction constants. [Ti(salen)O}2] was found to show the highest degree of Lewis acid catalysis, whereas two [VO(salen)X] (X=EtOSO3 or NCS) complexes both displayed lower degrees of Lewis acid catalysis. In the case of reactions
Hydroxynitrile lyases (HNLs) catalyze the enantioselective cleavage/formation of cyanohydrins. However, current methods for determining hydrocyanation are not suitable for mass screening of mutants for protein engineering of these biocatalysts. We demonstrate herein a chromogenic high‐throughput screening method for cyanohydrinsynthesis that is validated by either substrate profiling or the directed evolution
New stereoselective synthesis of thiamphenicol and florfenicol from enantiomerically pure cyanohydrin: a chemo-enzymatic approach
作者:Wenya Lu、Peiran Chen、Guoqiang Lin
DOI:10.1016/j.tet.2008.05.113
日期:2008.8
Thiamphenicol and florfenicol have been synthesized stereoselectively from enantiomericallypure 4-methylsulfanyl-mandelonitrile, which was obtained by hydrocyanation reaction of 4-methylsulfanyl-benzaldehyde catalyzed by (R)-hydroxynitrile lyase of Badamu (Prunus communis L. var. dulcis Borkh, almond from Xinjiang, China). It was found to be a highly effective bio-catalyst for this reaction after an