N-(2-(benzyloxy)-4-bromo-6-nitrophenyl)acetamide → 7-(benzyloxy)-5-bromo-2-methyl-1H-benzo[d]imidazole

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Reaction Steps

A mixture of N-{4-bromo-2-nitro-6-[(phenylmethyl)oxy]phenyl}acetamide (120 g, 329 mmol, STEP 1 in Example 1) and iron powder (55.1 g, 986 mmol) in acetic acid (500 mL) was refluxed with stirring for 6 hours. After cooling to room temperature, the mixture was filtered through a pad of Celite, and the filtrate was concentrated in vacuum. The residue was diluted with ethyl acetate (1.5 L). The resulted precipitates were filtered through a pad of Celite, and washed with ethyl acetate (500 mL). The filterate was concentrated in vacuum, and the residue was diluted with ethyl acetate (200 mL). The brine (800 mL) was added to the organic mixture, the resulted white precipitates were collected by filtration, and washed with water (200 mL) and diethyl ether (200 mL). The white solid was dissolved with dichloromethane/methanol (10:1, 1.0 L), dried over magnesium sulfate, and concentrated. The solid was triturated with diethyl ether (300 mL), collected by filtration, and dried in vacuum to afford the title compound as a white solid (54.7 g, 53%).

Provenance & Evidence