The Reaction of Piperazine-2, 5-dione with 2-Formylbenzoic Acid

Abstract

Reaction of piperazine-2, 5-dione with 2-formylbenzoic acid in the presence of triethylamine gives three products: 1-(3′-oxo-1′, 3′-dihydroisobenzofuran-1′-yl)piperazine-2, 5-dione, its 1, 4-bis analogue which had previously been identified as the 3, 6-compound, and 2, 2′-[3, 6-dioxopiperazine-2, 5-diylidene- bis(methylidyne)]bis(benzoic acid). The latter compound is shown by 1H and 13C n.m.r. spectroscopy to be the Z, Z isomer. © 1982 ASEG.