Hydrochloric Acid → 5-Bromo-1-methyl-1H-indazole

Participants

Reaction Steps

5-Bromo-1H-indazole (1r) (10 g, 51 mmol) in THF was added slowly to a cold solution of NaH (2.2 g, 60% wt in oil, 56 mmol) in THF under nitrogen. After 15 minutes, iodomethane (10.8 g, 76 mmol) was added to the dark solution at 0° C. After 2 hours, the mixture was poured into 1N HCl (30 mL) and extracted with EtOAc (2×50 mL), and the combined extracts were washed with brine (50 mL), dried over Na2SO4, filtered, and concentrated. Column chromatography (silica gel): hexane:EtOAc (10-40%) resulted in 8.2 g of final product (2r). 1H NMR (400 MHz, CDCl3) δ 7.9 (s, 1H), 7.84 (s, 1H), 7.43 (d, J=8.8 Hz, 1H), 7.24 (d, J=8.8 Hz, 1H), 4.04 (s, 3H); MS (ESI) m/z 213 (M+H)+.

Provenance & Evidence