To a solution of 5-bromo-1H-indazole (0.19 g, 0.94 mmol) in THF (3 mL), NaH (0.04 g, 1.03 mmol) was slowly added at 0 °C. The reaction mixture was stirred at this temperature for 1 h, followed by the addition of iodomethane (0.09 mL, 1.41 mmol) at 0 °C. The reaction mixture was allowed to warm slowly to room temperature and stirring was continued for 2 hours. Upon completion of the reaction, the reaction was quenched with water and concentrated under reduced pressure. The residue was diluted with water and extracted twice with dichloromethane (DCM). The organic layers were combined, dried over anhydrous sodium sulfate (Na2SO4), filtered and concentrated. Purification of the crude product by fast column chromatography (eluent: hexane/ethyl acetate = 10:1) afforded 5-bromo-1-methyl-1H-indazole (ii) (88.7 mg, 42.5%) and 5-bromo-2-methyl-2H-indazole (iii) (60.9 mg, 29%), both as white solids. The 1H-NMR (400 MHz, DMSO-d6) δ ppm of compound ii: 8.02 (d, 1H), 7.99 (d, 1H), 7.64 (d, 1H), 7.50 (dd, 1H), 4.04 (s, 3H). lcms (Method A): [MH]+ = 211/213, tR = 5.19 min. compound iii The 1H-NMR (400 MHz, DMSO-d6) δ ppm: 8.33 (s, 1H), 7.95 (d, 1H), 7.57 (d, 1H), 7.30 (dd, 1H), 4.16 (s, 3H). lCMS (Method A): [MH]+ = 211/213, tR = 4.95 min.
