Bromine → 3-Bromo-7-methylimidazo[1,2-a]pyridine

Participants

Reaction Steps

A cooled (−10° C.) suspension of 7-methylimidazo[1,2-α]pyridine (26 g, 0.2 mol) and sodium acetate (24.3 g, 0.3 mol) in methanol (150 ml) was treated with bromine (ca. 10 ml, 0.2 mol) added dropwise until the first permanent colour change occurred. Stirring was continued for a further 20 minutes before the reaction was poured into saturated aqueous sodium hydrogencarbonate (2 l). The resulting solid was filtered, washed with water and dried. Trituration with 5% ether in isohexane furnished 3-bromo-7-methylimidazo[1,2-α]pyridine as a red-brown powder (41.5 g, 100%). 1H NMR (360 MHz, CDCl3) δH 2.43 (3H, s), 6.76 (1H, d, J 7), 7.37 (1H, s), 7.53 (1H, s), 7.55 (1H, s), 8.00 (1H, d, J 7); m/z (ES+) 210/212 (M++H).

Provenance & Evidence