p-Toluenesulfonic acid monohydrate → 2-(Chloromethyl)-1-phenyl-1H-benzimidazole

Participants

Reaction Steps

A solution of 2-chloro-N-(2-anilinophenyl)acetamide (10 g) and p-toluenesulfonic acid monohydrate (4.5 g) in benzene (250 ml) was refluxed for 1.5 hours under an azeotropic dehydration. After being cooled to ambient temperature, the reaction mixture was diluted with an aqueous sodium bicarbonate solution and extracted with ethyl acetate three times. The combined organic layer was washed successively with water and brine, dried over anhydrous magnesium sulfate and evaporated under reduced pressure. The residual oil was purified by column chromatography on silica gel (100 g) with dichloromethane as an eluent to afford 2-chloromethyl-1-phenyl-1H-benzimidazole (3.4 g).

Provenance & Evidence