5,6-Dichloro-2-(4-methoxy-3-nitro-phenyl)-benzoimidazole-1-carboxylic acid benzyl ester → 2-(3-Amino-4-methoxy-phenyl)-5,6-dichloro-benzoimidazole-1-carboxylic acid benzyl ester

Participants

Reaction Steps

5,6-Dichloro-2-(4-methoxy-3-nitro-phenyl)-benzoimidazole-1-carboxylic acid benzyl ester (1.14 g, 2.4 mmol) from Step B was combined with glacial acetic acid (50 mL). Zinc dust (7.81 g, 120 mmol) was then gradually added to the stirred reaction mixture. After 2 hours, the zinc was filtered from the reaction mixture and the filtrate concentrated to an oil via rotary evaporation (60° C.). The oil was taken up in ethyl acetate and washed with saturated aqueous sodium bicarbonate solution and brine, dried (magnesium sulfate), filtered and the solvent removed. The solid was triturated with 7:3 hexane:ethyl acetate to give the product (0.6 g), mp 150-160° C.

Provenance & Evidence