Reinvestigation of tryptophan-dehydrobutyrine diketopiperazine structure

Abstract

Reinvestigation of the title natural product's structure (1) has shown the easy racemization of the Trp-stereocenter in some derivatives of cyclo-L-Trp-Gly. The here described synthesis of compound 2, a regioisomer of 1 with the N-methyl group on the nitrogen adjacent to the ethylidene side-chain, permits us to conclude that structure 1 was correct. © ARKAT.