A mixture of ethyl 3-[3-phenyl-1-[3-(2-pyridylaminocarbonyl)benzyl]-1H-pyrazol-4-yl]propionate (200 mg), 1 N aqueous sodium hydroxide solution (0.88 ml), ethanol (1 ml), and tetrahydrofuran (1 ml) was stirred at room temperature for one hour. 1 N hydrochloric acid (0.88 ml) was added to the reaction mixture, which was extracted with ethyl acetate. The ethyl acetate layer was washed with saturated aqueous sodium chloride solution, dried (MgSO4), and concentrated. The obtained crystals were collected by filtration, and 3-[3-phenyl-1-[3-(2-pyridylaminocarbonyl)benzyl]-1H-pyrazol-4-yl]propionic acid (110 mg, yield: 58%) was obtained. This was recrystallized from tetrahydrofuran-hexane. Melting point: 187–188° C.
