PROCESS FOR THE RESOLUTION OF RACEMATES OF OPTICALLY ACTIVE BICYCLIC IMINO- -CARBOXYLIC ESTERS, AND THE USE OF THE COMPOUNDS THUS OBTAINABLE FOR THE SYNTHESIS OF CARBOXYALKYLDIPEPTIDES

摘要

of the disclosure: The invention relates to a process for resolving racemic mixtures of bicyclic imino-.alpha.-carboxylic esters into the components by crystallization of diastereomeric salts, which comprises preparing the salts of the racemic esters with optically active N-acylated R- or S-amino-carboxylic acids which contain a phenyl nucleus, recrystallizing then from an organic solvent, decomposing the precipitated, optically homogeneous diastereomeric salts in a manner known per se, and isolating the enantiomers and, where appropriate, converting the latter into the free acids by hydrolysis in a manner known per se. The inven tion also relates to compounds of the formulae Ia and Ib indicated in the description, to diastereomeric salts of these compounds,and to a process for the preparation of optically pure compounds of the formula in which two of the radicals A, B1, B2 and C form a carbon chain and the others denote hydrogen, and r, R1, R2, X, Y and Z have the indicated meanings, which comprises reacting, in the presence of a condensing agent or, where appropriate, as the active esters, optically pure compounds of the indicated formulae Ia or Ib with optically pure compounds of the indicated formula III, eliminating the radical R by hydrogenolysis or hydrolysis and, where appropriate, converting the resulting optically pure compounds into physiologically tolerated salts.