A process for preparing an optically active cis-1,3-dibenzylhexahydro-1H-furo[3,4-d]imidazole-2,4-dione of the formula: ##STR1## wherein an asterisk (*) indicates an asymmetric carbon, Bzl represents a benzyl group and the 3a- and 6a-positions take the cis-configuration, which comprises reducing selectively an optically active cis-imidazolidinedicarboxylic acid monoester of the formula: ##STR2## wherein R is a C.sub.1 -C.sub.6 alkyl group and Bzl is as defined above with a reducing agent at either one of the carboxyl group and the alkoxycarbonyl group in the said monoester, followed by cyclization, the said monoester being the one obtainable by hydrolysis of a cis-imidazolidinedicarboxylic acid diester of the formula: ##STR3## wherein R and Bzl are each as defined above with an enzymatic material having a capability of hydrolyzing the ester group in the said diester.
一种制备光学活性的顺式-1,3-二苯基六氢-1H-
呋喃[3,4-d]
咪唑-2,4-二酮的方法,其
化学式为:##STR1## 其中星号(*)表示手性碳,Bzl代表苯甲基,3a-和6a-位置采取顺式构型,包括选择性还原式顺式
咪唑烷二
羧酸单酯的方法,其
化学式为:##STR2## 其中R是C.sub.1-C.sub.6烷基,Bzl如上所定义,使用还原剂在该单酯的羧基和烷氧基羰基之一上进行还原,然后进行环化,所述单酯是通过酶材料
水解式顺式
咪唑烷二
羧酸二酯得到的,其
化学式为:##STR3## 其中R和Bzl如上所定义,该酶材料具有
水解所述二酯中的酯基的能力。