A mixture of ethyl [4-butyl-2-methyl-6-oxo-5-{[2′-(5-oxo-4,5-dihydro-1,2,4-oxadiazol-3-yl)biphenyl-4-yl]methyl}pyrimidin-1(6H)-yl]acetate (0.25 g), 1 M aqueous sodium hydroxide solution (1.2 mL), tetrahydrofuran (3 mL) and ethanol (3 mL) was stirred at room temperature for 3 hr. 1 M hydrochloric acid (1.2 mL) was added to the reaction solution, and the mixture was stirred for 10 min. The reaction mixture was diluted with ethyl acetate, washed with saturated brine, and dried over anhydrous magnesium sulfate. The solvent was evaporated under reduced pressure to give the title compound as colorless crystals (0.22 g, 92%).
