Disclosed herein is a novel compound, (L)-menthyl 2-oxo-4-phenylbutyrate, and an improved process for making and isolating a substantially pure compound of the structural formula: ##STR1## wherein Y is hydrogen or (L)-menthyl the improvement which comprises: (a) stereoselectively reducing (L)-menthyl 2-oxo-4-phenylbutyrate by contacting said compound with S-B-(3-pinanyl)-9 horabicyclo[3,3,1]nonone, (b) stereoselectively isolating (L)-menthyl-(R)-2-hydroxy-4-phenylbutyrate by crystallization, and optionally hydrolyzing the so obtained ester; and further comprises optionally esterifying the so obtained acid by contacting said acid with a C.sub.1 -C.sub.6 alkanol in presence of acid.
本文披露了一种新化合物,(L)-薄荷醇
2-氧代-4-苯基丁酸酯,以及制备和分离结构式如下的基本纯化化合物的改进方法:##STR1## 其中Y为氢或(L)-薄荷醇,改进方法包括:(a)通过将化合物与S-B-(3-pinanyl)-9 horabicyclo[3,3,1]nonone接触来立体选择性地还原(L)-薄荷醇
2-氧代-4-苯基丁酸酯,(b)通过结晶立体选择性地分离(L)-薄荷醇-
(R)-2-羟基-4-苯基丁酸酯,并且可以
水解所得酯;进一步包括通过在酸的存在下将所得酸与C.sub.1-C.sub.6烷醇接触来选用酯化所得酸。