To a solution of 4′-[(2-butyl-4-cyclopropyl-6-oxopyrimidin-1(6H)-yl)methyl]biphenyl-2-carbonitrile (5.22 g) in acetic acid (60 mL) was added bromine (1.39 mL), and the mixture was stirred at 70° C. for 2 hr. The reaction mixture was diluted with ethyl acetate, washed with 1 M aqueous sodium thiosulfate solution, saturated aqueous sodium hydrogen carbonate and saturated brine, and dried over anhydrous sodium sulfate. The solvent was evaporated under reduced pressure and the residue was purified by silica gel column chromatography to give the title compound (5.4 g, 80%) as a colorless solid.
