To a stirred mixture of the crude product from Example 3, 20 ml of acetone and 4.7 g of sodium carbonate was added dropwise 2.8 g (8.21 mmole) of 5-benzyloxy-2-(2,2,2-trifluoroethoxy)benzoyl chloride in 10 ml of acetone. The mixture was stirred at about 20° C. for about 16 hours. To the mixture was added 50 ml of acetone, and the resulting inorganic residue was separated by filtration and washed with acetone. The filtrate and washings were combined and evaporated. This residue was dissolved in benzene, and the solution was washed sequentially with 10% aqueous sodium carbonate solution, 2% acetic acid, water, saturated aqueous sodium bicarbonate solution and saturated aqueous sodium chloride solution. The organic solution was dried over magnesium sulfate, and then filtered and evaporated. The residue was boiled in carbon tetrachloride, and the mixture was cooled and the solid was separated by filtration. The solid was purified by chromatography on 30 g of silica gel. The column was eluted sequentially with 5% ethyl acetate in dichloromethane and 2% methanol in dichloromethane. The product was obtained as a white solid, 6-[5-benzyloxy-2-(2,2,2-trifluoroethoxy)benzamidomethyl]-2(1H)-pyridone. The structural assignment was supported by infrared and nuclear magnetic resonance spectral analyses.
