Synthesis of 3-methylthio-1-phenyl-pyrazolo[3,4-d][1,2,4]triazolo[1,5-a]pyrimidin-4-one derivatives via tandem aza-Wittig reaction

Abstract

An efficient and convenient procedure for the synthesis of 3-methylthio-1-phenyl-pyrazolo[3,4-d][1,2,4]triazolo[1,5-a]pyrimidin-4-one derivatives (4a–m) via tandem aza-Wittig and annulation reactions with iminophosphoranes 1, aryl isocyanate, and substituted 2-phenoxyacetohydrazide is described. This protocol provides a simple and facile approach to synthesize pyrazolo[3,4-d][1,2,4] triazolo[1,5-a]pyrimidine derivatives under mild conditions.