反应 #502067

反应方程式

cyanohydrins

Citrate Phosphate

Phenyllactic acid

→

6a

(S)-phenyllactic acid

反应条件

实验过程

We next examined the preparation of aryllactic acid derivatives 6 through hydrolysis of the corresponding cyanohydrins 5. Phenyllactic acid and derivatives serve as versatile building blocks for the preparation of numerous biologically active compounds. (Coppola, G. M.; Schuster, H. F. Chiral α-Hydroxy Acids in Enantioselective Synthesis; Wiley-VCH: Weinheim, Germany: 1997.) Upon screening our nitrilase library against the parent cyanohydrin 5a (Ar=phenyl), we found several enzymes that provided 6a with high enantiomeric excess. One enzyme, SEQ ID NOS: 103, 104, was further characterized. After optimization, SEQ ID NOS:103, 104, was shown to provide (S)-phenyllactic acid (6a) with complete conversion (50 mM) and very high enantioselectivity (98% ee) over 6 h. The highest enantioselectivity previously reported for biocatalytic conversion of 5 to 6 was 75% ee achieved through a whole cell transformation using a Pseudomonas strain. (Hashimoto, Y.; Kobayashi, E.; Endo, T.; Nishiyama, M.; Horinouchi, S. Biosci. Biotech. Biochem. 1996, 60, 1279.)

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