Sodium hydride (60%, oily, 180 mg) was added to a mixture of ethyl 3-(3-phenyl-1H-pyrazol-4-yl)propionate (1.00 g), benzyl 4-chloromethylbenzoate (1.17 g), and N,N-dimethylformamide (10 ml) at 0° C., and the mixture was stirred for 2.5 days at room temperature. The reaction mixture was poured into water, which was extracted with ethyl acetate. The ethyl acetate layer was washed with saturated aqueous sodium chloride solution, dried (MgSO4), and then concentrated. The residue was subjected to silica gel column chromatography, and benzyl 4-[4-(3-ethoxy-3-oxo-1-propyl)-3-phenyl-1H-pyrazole-1-ylmethyl]benzoate (1.68 g, yield: 88%) was obtained as a colorless oily substance from the fraction eluted with ethyl acetate-hexane (1:4, volume ratio).
