Abstract 1, 3, 5-Trisubstituted pyrazolines to pyrazoles are carried out efficiently in the presence of new reagents N, N, N′, N′-tetrabromo-benzene-1, 3-disulfonylamine [TBBDA] and N, N′-dibromo-N, N′-1, 2-ethanediylbis-(p-toluenesulphonamide)[BNBTS] in solvent- free conditions with catalytic amounts of SiO 2 under microwave irradiation in high yields.
