5-Bromoindazole (590 mg, 2.99 mmol) was dissolved in tetrahydrofuran (10 mL) and stirred under ice bath conditions and sodium hydride (180 mg, 80% dispersed in mineral oil, 6.00 mmol) was added slowly. After stirring for 30 minutes, iodomethane (468 mg, 3.30 mmol) was added and stirring was continued for 3 hours. After completion of the reaction, the reaction mixture was warmed to room temperature and the reaction was quenched by the addition of water (20 mL). The reaction was extracted with ethyl acetate (20 mL × 3), and the organic phases were combined and washed with saturated saline (50 mL × 3). The organic phase was dried with anhydrous sodium sulfate, filtered and the solvent was removed by rotary evaporation. The residue was purified by column chromatography (eluent: petroleum ether/ethyl acetate = 10:1 to 3:1) to afford 5-bromo-2-methyl-2H-indazole (A14-2, 230 mg, 36%) and 1-methyl-5-bromo-1H-indazole (A14-3, 330 mg, 52%).A14-2 was an off-white solid, 1H NMR (400 MHz, DMSO ) δ 8.33 (s, 1H), 7.96-7.95 (m, 1H), 7.57 (d, J = 9.2 Hz, 1H), 7.31-7.28 (m, 1H), 4.16 (s, 3H).A14-3 is a white solid.
