Cycloaddition Reactions of 3-Dimethylamino-1-methyl-1,2,4-triazinium-5-olates With Dimethyl Acetylenedicarboxylate

Abstract

The cycloaddition reactions of some 3-dimethylamino-1-methyl-1,2,4-triazinium-5-olates (1) with dimethyl acetylenedicarboxylate ( dmad ) were studied. The products in all cases were found tobe dimethyl 4-dimethylamino-1-methyl-6-oxo-1,3a,6,6a-tetrahydropyrrolo[3,4-c]pyrazole-3,3a-dicarboxylate derivatives (2). The structure determinations were carried out by ¹H and ¹³C n.m.r. and mass spectrometry, and for one derivative by single-crystal X-ray diffractometry. The mechanism of the reaction is also discussed.