N-[5-(3,4,5,6-Tetramethoxy-2-methylbenzyl)-2-(3-pyridyl)benzoyl]-4-trifluoromethylaniline (60 mg, 0.1060 mmol) was dissolved in a mixed solvent of acetonitrile (9 ml) and water (3 ml), then CAN (228 mg, 0.4237 mmol) was added thereto at room temperature and the mixture was stirred for 3 hours. The reaction solution was poured into water and extracted with ethyl acetate. The extract was washed with water and dried and the solvent was evaporated therefrom. The residue was purified by preparative thin layer chromatography (methylene chloride:methanol=95:5) to give the title compound (18 mg, 0.0335 mmol, 32%).
