Benzimidazole → HCID 22727953, compound

Participants

Reaction Conditions

Reaction Steps

A suspension of 6-bromo-3-(3-methoxyphenyl)-3H-imidazo[4,5-b]pyridine (10.7 g, 35 mmol) in hydrobromic acid (80 ml of a 30 wt. % solution in acetic acid) was heated at 100° C. for 20 hours. After cooling to ambient temperature the reaction mixture was slowly dissolved in excess 3N sodium hydroxide, keeping the temperature <20° C. (to prevent hydrolysis of the benzimidazole back to the bis-amine). The aqueous phase was extracted with ether (×2) then adjusted to pH 7 with concentrated hydrochloric acid. The resulting solid was collected by filtration, washed with water and dried under high vacuum to give 3-(6-bromoimidazo[4,5-b]pyridin-3-yl)phenol as a beige-coloured solid (10.2 g, 99%); δH (400 MHz, d6-DMSO) 6.88 (1H, ddd, J 8, 2 and 1), 7.28 (1H, ddd, J 8, 2 and 1), 7.35-7.41 (2H, m), 8.52 (2H, dd, J 11 and 2), 8.91 (1H, s), 9.96 (1H, br s); m/z (ES+) 290 and 292 (M++H).

Provenance & Evidence