To a degassed solution of 6-amino-5-bromo-2-(4-fluorophenyl)-N-methyl-2H-indazole-3-carboxamide (0.75 g, 2.1 mmol) in DCM/Pyridine (10 mL/3 mL) was added MsCl (1.2 g, 10.5 mmol) under N2 at 0° C. for 30 min. The reaction was stirred at 25° C. for 8 hours. The reaction mixture was diluted with water, extracted with EtOAc and washed with brine, and then dried over Na2SO4. After concentration, the residue was purified by column chromatography (PE:EA=2:1) to give crude 5-bromo-2-(4-fluorophenyl)-N-methyl-6-(methylsulfonamido)-2H-indazole-3-carboxamide (0.65 g, yield: 78%). 1H-NMR (CDCl3, 400 MHz) δ 8.30 (s, 1H), 8.03 (s, 1H), 7.56˜7.60 (m, 2H), 7.20˜7.25 (m, 2H), 6.97 (s, 1H), 5.73 (s, 1H), 3.08 (s, 3H), 2.99 (d, J=4.8 Hz, 3H). MS (M+H)+: 441/443.
