Abstract
Diazonium salts of sulfones 1a,b are coupled with malononitrile to yield hydrazones 2a,b. Refluxing of the hydrazones 2a,b with hydrazine hydrate in ethanol furnished the aminopyrazoles 3a,b. The behaviour of aminopyrazole 3a towards some electrophilic reagents is investigated. Thus, aminopyrazole 3a is reacted with chalcones, arylidenemalononitriles and ketene dithioacetal, to give the pyrazolo[1, 5-a]pyrimidine derivatives 6, 11 and 14 respectively. Pyrazolotriazine derivative 21 is obtained by treatment of compound 3a with dicyandiamide in DMF under reflux. The structures of synthesized compounds are established on the basis of elemental and spectral data. Also, some of synthesized compounds are tested in vitro for their antimicrobial activity.