| 摘要 |
<p>ROGERS, BERESKIN /A PARR 0750-760 H0E 83/F 266 of the disclosure: . The invention relates to a process for resolving racemic mixtures of bicyclic imino-.alpha.-carboxylic acid esters into the components of the formula Ia and Ib (Ia) (Ib) in which R1 stands for an aliphatic, cycloaliphatic, aromatic or araliphatic radical, A denotes hydrogen and B and C together form a carbon chain or C denotes hydrogen and A and B together form a carbon chain, by crystallizing diastereoisomeric salts, which comprises preparing the salts of the racemic esters with optically active 0,0-diacyltartaric acids in a suitable solvent in which only one of the two diastereoisomeric salts crystallizes in optically pure form, if desired purifying the diastereoisomeric salt by recrystallization, reprecipitatien or trituration, and finally adding bases to the salt to cleave it into the pure enantiomer of the formula Ia or Ib. Bicyclic imino-.alpha.-carboxylic acid esters can be used as starting materials in the synthesis of optically pure angiotensin converting enzyme inhibitors useful for treating high blood pressure. The invention also relates to diastereoisomeric salts of an ester of the formula Ia or Ib and a diacyltartaric acid.</p> |
