To a solution of methyl 4-({cyclohexyl[1-(3-ethoxyphenyl)-3-ethyl-1H-pyrazol-4-yl]methyl}amino)benzoate (0.34 g) synthesized in the above-mentioned (1) in ethanol (6.0 mL) was added 1N aqueous sodium hydroxide solution (6.0 mL), and the mixture was stirred at 60° C. for 6 hr. Ethanol was evaporated under reduced pressure, and 1N hydrochloric acid (8.0 mL) was added to the residue, and the mixture was extracted with ethyl acetate. The extract was washed with saturated brine, dried over magnesium sulfate, and concentrated under reduced pressure to give a crude product (0.33 g, quantitative) of the title object compound as a yellow oil.
