Abstract
Condensation of chalcones (1-3) with p-sulfamylphenylhydrazine hydrochloride in presence of sodium acetate afforded the corresponding hydrazones (13-15). Subsequent boiling of the hydrazones (13-15) in ethanol containing few drops of hydrochloric acid gave the corresponding pyrazolines (7-9). Oxidation of the pyrazolines (7-9) with aq bromine furnished 3, 5-disubstituted pyrazoles (16-18). When pyrazolines (10-12) were treated with bromine in chloroform, they underwent oxidative bromination giving the dibromopyrazoles (19-21).