A process for preparing an optically active cis-1,3-diben- zylhexahydro-1 H-furo[3,4-d]imidazole-2,4-dione of the formula:
wherein an asterisk (*) indicates an asymmetric carbon, Bzl represents a benzyl group and the 3a- und 6a-positions take the cis-configuration, which comprises reducing selectively an optically acitve cis-imidazolidinedicarboxylic acid monoester of the formula:
wherein R is a C1-C6 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 that obtainable by hydrolysis of a cis-imidazolidinedicarboxylic acid diester of the formula:
wherein R and Bzl are each as defined above with an enzymatic material capable of hydrolyzing the ester group in the said diester.
一种制备光学活性顺式-1,3-二苄六氢-1 H-
呋喃并[3,4-d]
咪唑-2,4-二酮的工艺,其式如下
其中星号(*)表示不对称碳,Bzl表示苄基,3a-和6a-位为顺式构型,包括选择性还原式中的光学活性顺式
咪唑烷二
羧酸单酯:
其中 R 为 C1-C6 烷基,Bzl 如上定义,在上述单酯中的羧基和烷氧羰基中的任一基团上用还原剂还原,然后环化,上述单酯是通过
水解式如下的顺式
咪唑烷二
羧酸二酯得到的:
其中 R 和 Bzl 分别如上文所定义,使用一种能
水解上述二酯中酯基的酶材料。