Abstract A study of the preparation of carbobenzoxy-dipeptide p-nitrophenyl esters revealed that partial racemization may occur depending on the structure of the dipeptide derivative used. Whereas carbobenzoxy-S-benzyl-L-cysteinyl-L-tyrosine yielded an optically pure ester employing the sulfite method, the synthesis of the ester of carbobenzoxy-L-tyrosine by various methods proceeded with partial racemization. The optically pure carbobenzoxy-L- ...
