5,6-Dimethylbenzimidazole → 5,6-dimethyl-1-(4-nitrobenzyl)-1H-benzimidazole

Participants

Reaction Conditions

Reaction Steps

A mixture of 5,6-dimethyl-1H-benzimidazole (5.0 g), 4-nitrobenzyl bromide (6.16 g), potassium carbonate (7.88 g) and N,N-dimethylformamide (60 ml) was stirred at 60° C. for 14 hrs. The reaction mixture was poured into water, and the mixture was extracted with ethyl acetate. The organic layer was washed with water, dried over anhydrous magnesium sulfate, and concentrated. The residue was subjected to silica gel column chromatography to give 5,6-dimethyl-1-(4-nitrobenzyl)-1H-benzimidazole (2.6 g, 32%) as crystals from a fraction eluted with methanol-ethyl acetate (1:20, v/v). Recrystallization thereof from ethyl acetate-hexane gave pale-red prism crystals. melting point: 175-177° C.

Provenance & Evidence