To a solution of 5-bromo-7-(trifluoromethyl)-1-[3-(trifluoromethyl)benzyl]-1,3-dihydro-2H-benzimidazol-2-one (171.9 mg) and copper(I) cyanide (76.3 mg) in N,N-dimethylformamide (10 ml) was heated at reflux for 11 hours. Copper(I) cyanide (51.0 mg) was further added, and the mixture was heated at reflux for 13 hours. To the reaction mixture was added saturated aqueous sodium bicarbonate solution, and the mixture was extracted 5 times with chloroform. The organic layer was dried over anhydrous magnesium sulfate, and concentrated in vacuo to give the title compound (139.5 mg, 93%).
