Microwave mediated facile synthesis of some novel pyrazole, pyrazolo [1,5-a] pyrimidine and pyrazolo [5,1-c][1,2,4] triazin derivatives

4-Phenyl-2H-pyrazol-3ylamine 3 has been prepared by reaction of 2-phenyl-3-piperidine-1-yl-acrylonitrile [6] with hydrazine hydrate under microwave irradiation. Compound 3 reacted with acetylacetone and ethyl acetoacetate to yield pyrazolopyrimidine derivatives 7 and 8, respectively. Pyrazolopyrimidine derivative II can be formed by reaction of 3 with 2-ethoxymethylene-malononitrile. Compound 3 can be diazotized to yield the diazonium chloride and coupled with 6 to yield pyrazolotriazine derivative 25. Structures of the synthesized compounds were confirmed by their IR and NMR spectroscopic data