Preparation Of (R)-2Hydroxy-4-phenylbutyrate By Biotransformation

(R)-2-hydroxy-4-phenylbutyrate (R-HPBE) is a key chiral intermediates in the synthesis of angiotensin converting enzyme inhibitor (ACEI). By blocking the renin-angiotensin-aldosterone system, ACEI can prevent the generation of angiotensin II, which helps dilate blood vessels and reduce hypertension. So far, there are18kinds of ACEI on the market.(R)-2-hydroxy-4-phenylbutyrate is an important structural unit of ACEI, such as enalapril, lisinopril and other drugs can be synthesized by coupling with different amino.micro-organisms have been used to reduce2-oxo-4-phenylbutyrate (EOPB) for the preparation of R-HPBE. In this paper, Candida utilis1257was studied, the conversion rate was71.4%and the enantiometric excess of R-HPBE was37.2%. Candida utilis1257was mutated by UV and finally we got Candida utilis1257-710, The conversion rate reached100%, e.e. value of R-HPBE reached46%, Then the Conversion reaction conditions was optimized, the concentration of substrate is12.5mg/L, ethanol was added in1%(v/v), at30℃,180r/min shake speed for24h, and the conversion is100%, e.e. value of R-HPBE reached62.5%. The affection of Inhibitors and Inducers on the conversion reaction was studied, the results show that when CHCl3was used as an inhibitor, the e.e. value of R-HPBE could reach100%, but the conversion rate was only10%.lipase AK resolution of EOPB by transesterification was carried out to prepare R-HPBE. At30℃,120r/min shaking speed,0.022mol/L of the initial substrate concentration, added AK enzyme20mg in2ml of the reaction system, reacted for3d, the substrate conversion rate reached49.5%, the e.e. value of R-HPBE reached97.9%.The mechanism of transesterification catalyzed by reaction lipase AK is ping-pong mechanism, so we can derive the enzyme kinetic model. Based on the experimental results, the optimal fitting parameters were obtained. and finally we got the mathematical expressions of the enzyme kinetic model:...