Synthesis of 8a-Chlorotetrahydropyrrolo[1,2-H]pyrazine-1,6,7-(2H)-triones from 3-Methylidenepiperazin-2-ones and Oxalyl Chloride

Abstract

(Z)-1-Aryl-3-(2-aryl-2-oxoethylidene)piperazin-2-ones react with oxalyl chloride at cooling with the formation of (Z)-2-aryl-8-[hydroxy(aryl)methylidene]-8а-chlorotetrahydropyrrolо[1,2-a]pyrazine-1,6,7(2H)-triones. At heating HCl is eliminated from them to produce 8-aroyl-3,4-dihydropyrrolо[1,2-а]pyrazine- 1,6,7(2H)-triones.