DIAZOALKYLIDENEAMINE-1,2,3-TRIAZOLE RING- CHAIN TAUTOMERISM IN 1,2-TRIAZOLO[1,5-c] PYRIMIDINES

Abstract

Triazolopyrimidines have been synthesized and the unknown diazoalkylidine amine ring-chain tautomerism demonstrated for this ring system. Acetamidine-hydrochloride reacted readily with diethylacetonedicarboxylate in ethanolic sodium ethoxide to give pyrimidinone (8). Treatment of the pyrimidinone with toluene-p-sulponyl azide in trimethylamine gave diazo-compound which cyclised readily when heated under reflux in dimethylsulphoxide for 24 hours to afford the expected 1,2,3-triazolo[1,5-c]pyrimidinone (11) in a good yield. Also described is the condensation of diethylacetonedicarboxylate with a triazole in acetic acid to give another product acetoxybenzyl pyrimidinone (17).

Key words: Triazolopyrimidines, Acetamidine HCl, toluene-p-sulponyl azide, ring-chain tautomerism