To a suspension of 3-(β-D-glucopyranosyloxy)-4-[(4-isopropoxyphenyl)methyl]-5-methyl-1H-pyrazole (0.050 g) and cesium carbonate (0.20 g) in N,N-dimethylformamide (1 mL) was added cyclopentyl bromide (0.055 g) at 80° C., and the mixture was stirred for 30 minutes. After cooling to room temperature, water was added to the reaction mixture, and the mixture was purified by solid phase extraction on ODS (washing solvent: distilled water, eluent: methanol), and successively by column chromatography on silica gel (eluent: dichloromethane/methanol=8/1) to give 1-cyclopentyl-3-(β-D-glucopyranosyloxy)-4-[(4-isopropoxyphenyl)methyl]-5-methyl-1H-pyrazole (0.034 g).
