6-Methyl 3-{4-cyclopropyl-5-[3-(2,2-dimethylpropyl)cyclobutyl]isoxazol-3-yl}adipate (100 mg), 4-chloro-2-methylphenylamine (43.5 mg) and DMF (1 mL) were mixed. To the mixture were added HOBt.H2O (47 mg) and WSC.HCl (58.8 mg) at ice temperature. The mixture was stirred at RT, and further stirred at 70° C. To the reaction mixture was added saturated aqueous sodium bicarbonate at ice temperature. The mixture was extracted with ethyl acetate. The organic layer was washed with water and brine, then dried over magnesium sulfate. The magnesium sulfate was filtered off and the filtrate was concentrated in vacuo. The resultant residue was purified by preparative chromatography (Eluent: ethyl acetate/hexane=1/4) to give the title compound (72.8 mg).
