Intermediate 3. Synthesis of 6-bromo-1-methyl-1H-indazol-3-amine: 6-bromo-1H-indazol-3-amine (788 mg, 3.71 mmol) was dissolved in dimethylformamide (3 mL) and cooled to 0 °C. Sodium hydride (60% oil dispersion; 163 mg, 6.79 mmol) was added in batches under stirring. The reaction mixture was continued to be stirred at 0 °C for 30 min. Subsequently, iodomethane (225 μL, 4.09 mmol) was added dropwise to the mixture and the reaction was stirred for 2 h at room temperature. Upon completion of the reaction, water was added to the crude reaction mixture and a red solid was precipitated. The solid was collected by filtration and dried to afford the title compound in 80% yield. The product was analyzed by LRMS showing m/z: 226 (M)+, 228 (M + 2)+. 1H NMR (300 MHz, DMSO-d6) δ ppm: 3.75 (s, 3H); 5.7 (s, 2H); 7.01 (d, 1H); 7.59 (d, 1H); 7.6 (s, 1H).
