Trityl chloride → 3H-Imidazo[4,5-b]pyridine, 6-bromo-3-(triphenylmethyl)-

Participants

Reaction Steps

To a solution of 6-bromo-1H-imidazo[4,5-b]pyridine (2.7 g, 11.0 mmol) in dimethylformamide (30 mL) at 0° C. was added 60% sodium hydride in mineral oil (0.53 g, 13.2 mmol) and the reaction mixture was stirred for 30 minutes, followed by the addition of a solution of triphenylmethyl chloride (3.2 g, 11.55 mmol) in dimethylformamide (5 mL). The reaction mixture was stirred at room temperature for 24 hours then quenched by the careful addition of water then partitioned with ethyl acetate (250 mL). The organic phase was washed with 10% aqueous citric acid (2×, 100 mL), brine (100 mL), saturated sodium bicarbonate (100 mL), brine (100 mL) then dried over anhydrous sodium sulfate, filtered and concentrated. Silica gel chromatography (hexane ethyl acetate 9:1 to 4:1) provided 6-bromo-3-trityl-3H-imidazo[4,5-b]pyridine (1.8 g, 37%). 1H NMR (400 MHz, CDCl3): 8.18 (d, 1H), 8.14 (d, 1H), 8.02 (s, 1H), 7.36-7.28 (m, 10H), 7.18-7.14 (m, 5H) and 6-bromo-1-trityl-1H-imidazo[4,5-b]pyridine (2.9 g, 60%) 1H NMR (400 MHz, CDCl3): 8.50 (d, 1H), 8.14 (s, 1H), 7.38-7.34 (m, 10H), 7.16-7.12 (m, 5H), 6.84 (d, 1H).

Provenance & Evidence