Synthesis, Biological Activity and Cytotoxicity of New Fused Pyrazolo[1,5-a]pyrimidine from 5-Aminopyrazole Incorporated with p-Chloroaniline

5-Amino-3-(4-chlorophenylamino)-1H-pyrazole-4-carbonitrile 3 was prepared in high yield from the reaction of hydrazine hydrate with known 2-[(4-chlorophenylamino)(methylthio)methylene]malononitrile 2a (which was prepared from reaction of 2-[bis(methylthio)methylene]malononitrile 1 with p-Chloroaniline) under reflux in ethanol. The compound 3 was utilized as a key intermediate for the synthesis of pyrazolo[1, 5-a]pyrimidines 4a-b, 5a-c and 6 by reactions with some of ketene-S, S-and N, S-acetals. The antibacterial and antifungal activities, as well cytotoxicity against Breast cancer cells (MCF7) of some selected compounds are also reported.