酵母发酵液催化不对称还原反应合成(S)-4-氯-3-羟基-丁酸乙酯的条件优化

Optimization for the asymmetric synthesis of (S)-ethyl 4-chloro-3-hydroxybutanoate directly catalyzed by yeast fermentation broth

目的优化酵母发酵液直接催化4-氯乙酰乙酸乙酯(COBE)合成(S)-4-氯-3-羟基-丁酸乙酯((S)-CHBE)的反应条件.方法考察酵母发酵液催化该反应过程中基质变化的规律,研究底物和能源供体对反应的影响,并通过正交实验设计法优化反应条件.结果在酵母发酵液催化COBE不对称还原反应的过程中,底物和还原糖消耗、产物合成相对集中在反应的前期;反复分批式添加底物和蔗糖有利于反应效率的提高;正交实验优化反应条件的结果表明酵母发酵液直接催化COBE不对称还原反应合成(S)-CHBE的最佳反应条件为蔗糖添加方式Ⅱ(反应开始2h后添加5g/120mL),底物添加方式Ⅳ[0.5(3)],缓冲剂添加量2g/120mL,β-环糊精添加量为2g/120mL,反应后测定产物的产率达96%,ee(对映体过量值)达100%.结论通过反应条件优化提高了酵母发酵液的催化效果.

AIM： To optimize the asymmetric reduction of ethyl 4-chloro-3-oxobutanoate （ COBE ） to （ S ）-ethyl 4-chloro-3- hydroxybutanoate [ （S）-CHBE ] directly catalyzed by yeast （Saccharomyces cerevisiae ） fermentation broth. METHODS： The variation of COBE, （S）-CHBE and reductive sugar in reaction course and the influence of some reaction conditions （ substrate, energy source） on asymmetric synthesis of （S）-CHBE directly catalyzed by yeast fermentation broth were examined respectively, and the optimal conditions of asymmetric synthesis of （S）-CHBE were optimized by orthogonal test design. RESULTS： The consumption of substrate and formation of product were mostly in the initial reaction course as well as consumption of reductive sugar. Repeated feeding strategy of substrate and energy source was favored for the formation of （ S）-CHBE. The optimum reaction conditions were sucrose repeated feeding strategy Ⅱ （feeding 5 g/120 mL after 2 h of reaction） , substrate feeding strategy Ⅳ [0. 5 （ 3 ） ], buffer concentration 2 g/120 mL, β-cyclodextrin concentration 2 g/120 mL. CONCLUSION： Optically active （S）-CHBE is synthesized by yeast fermentation broth with 96% yield and 100% ee （enantiometric excess） under the optimum reaction conditions.