3-Fluoro-N-(3-phenyl-1H-indazol-5-yl)-benzenesulfonamide can be obtained in the following way: a solution of 0.4 g of N-(N-tert-butoxycarbonyl-3-phenyl-1H-indazol-5-yl)-3-fluorobenzenesulfonamide, of 3.5 ml of chloroform and of 0.127 ml of iodotrimethylsilane is maintained with stirring for 18 hours at a temperature in the region of 20° C. 10 ml of 5% aqueous ammonia are added to the reaction medium, which is extracted with 40 ml of dichloromethane. The organic phase is dried over magnesium sulfate, filtered and concentrated by evaporation under reduced pressure. The residue thus obtained is purified by chromatography on a silica column with a dichloromethane/methanol (99/1 by volume) mixture. The gray solid thus obtained is recrystallized from 25 ml of dichloromethane in the presence of 3 S black. 0.1 g of 3-fluoro-N-(3-phenyl-1H-indazol-5-yl)benzenesulfonamide is thus obtained in the form of a white solid melting at 200° C. (analysis C19H14FN3O2S % calculated C, 62.11; H, 3.84; F, 5.17; N, 11.44. % found C, 62.09; H, 3.69; F, 4.88; N, 11.44).
