A mixture of 4-bromo-7-(1-ethylpropyl)-1-methyl-1,3-dihydro-2H-benzimidazol-2-one (300 mg, 1.01 mmol) and copper cyanide (116 mg, 1.30 mmol) in 1-methyl-2-pyrrolidone (3 mL) was irradiated by microwave (200 w) at 150° C. for 1 h. After cooling, to the reaction mixture was diluted with saturated sodium bicarbonate, and extracted with ethyl acetate. The extract was dried over magnesium sulfate, filtered, and concentrated in vacuo. The residue was washed with 50% diisopropyl ether/n-hexane to give the title compound (209 mg, 86%).
