Preparation of optically active cis-1,3-dibenzyl-hexahydro-1H-furo[3,4-d]imidazole-2,4-dione and its intermediates
AssigneeSumitomo Chemical Company, Limited
InventorsNaohito Ohashi, Kozo Shimago, Takaharu Ikeda, Kikuo Ishizumi
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Abstract
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.
Claims17
A process for preparing an optically active cis-imidazolidinedicarboxylic acid monoester of the formula:
- ##STR8## wherein R is a C.sub.1 -C.sub.6 alkyl group, Bzl represents a benzyl group and the 4- and 5-positions take the 4S,5R-configuration, which comprises hydrolyzing a cis-imidazolidinedicarboxylic acid diester of the formula:
- ##STR9## 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.
A process for preparing an optically active cis-1,3-dibenzylhexahydro-1H-furo[3,4-d]imidazole-2,4-dione of the formula:
- ##STR10## 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:
- ##STR11## wherein R is a C.sub.1 -C.sub.6 alkyl group and Bzl is as defined above with a reducing agent prepared from sodium borohydride and boron trifluoride for selective reduction of the carboxyl group or with sodium borohydride, in a mixture of at least one alcoholic solvent and at least one aprotic solvent, as the reducing agent for selective reduction of the alkoxycarbonyl group, followed by cyclization.
Dependencies are inferred from the claim text.