Iminophosphoranes in Heterocyclic Synthesis: Synthesis of Pyrazolo[1,5-a]pyrimidine, Imidazo[1,2-b]pyrazole and Pyrazolo[1,5-b][1,2,4]triazine Derivatives via Intermolecular Aza-Wittig Reactions

Series of pyrazolo[1,5-a]pyrimidine derivatives, imidazo[1,2-b]pyrazole derivative and pyrazolo[1,5-b][1,2,4]triazine derivatives were obtained by the initial reaction of 5-(triphenylphosphoranylideneamino)-1H-pyrazole derivative with carbonyl compounds and hydrazonyl halides.The newly synthesized compounds were confirmed by spectral and analytical data.