Synthesis of dehydroamino acids and didehydrodioxopiperazines and their conversion into α‐mercapto‐α‐amino acid derivatives

Abstract

Abstract A synthesis of α,β‐dehydroamino acid derivatives 12 is described, which is of possible general applicability and might be useful for the preparation of peptides which have such a moiety in their sequence. In addition, several didehydrodioxopiperazines ( 13–17 ) have been prepared. The reactivity of these compounds towards liquid H 2 S in the presence of ZnCl 2 has been studied. Only the dehydroalanine derivatives 12a and 13 gave α‐addition products; all other dehydroamino acid derivatives and cyclic dipeptides failed to react cleanly.