Pyrazine Chemistry. II Reduction of 3, 6-Dibenzylidenepiperazine-2, 5-diones

Abstract

A reinvestigation of the reduction of 3, 6-dibenzylidenepiperazine-2, 5-dione (1) with zinc and acetic acid established that this reaction gave (Z)-6-benzyl-3-benzylidenepiperazine-2, 5-dione (10). When a mixture of acetic acid and hydrochloric acid was used in the reduction, a mixture of trans- (12) and cis-3, 6-dibenzylpiperazine-2, 5-dione (5) was obtained. Direct catalytic reduction of 3, 6-di(2-chloro- benzylidene)piperazine-2, 5-dione (2) to (±)-cii-3, 6-di(2-chlorobenzyl)piperazine-2, 5-dione (6) was also accomplished. Show more