4-Fluorobenzene-1,2-diamine → 6-Fluoro-2-methyl-1H-benzimidazole

Participants

Reaction Steps

Ethyl acetimidate hydrochloride (37.1 g, 0.3 mol) was added to a stirred suspension of 4-fluoro-ortho-phenylenediamine (12.6 g, 0.1 mol) in ethanol (150 ml) at 0° C. The mixture was allowed to warm up to room temperature and stirred overnight. The solvent was removed under reduced pressure and the residue extracted into ethyl acetate (100 ml), washed with water (3×100 ml), dried over anhydrous magnesium sulphate, filtered and evaporated. Crystallisation from ethyl acetate gave 2-methyl-5-fluorobenzimidazole (7.7 g, 51%) as a brown crystalline solid.

Provenance & Evidence