A mixture of sodium hydride (60% dispersion in mineral oil, 0.13 g) in DMF (5 ml) was stirred under ice-cooling for 5 min. and methyl 2-ethylamino-1-[(2′-cyanobiphenyl-4-yl)methyl]benzimidazole-7-carboxylate (0.95 g) was added to the mixture, followed by stirring for 10 min. To the mixture was added methyl iodide (0.2 ml) and the mixture was stirred for 20 min. To the reaction mixture was added water and the mixture was extracted with ethyl acetate. The extract was washed with water, dried and evaporated to dryness. The residue was purified by column chromatography on silica gel to give crude crystals, which were recrystallized from ethyl acetate-hexane to afford colorless needles (0.88 g, 82%), m.p. 66-69° C.
