To a solution of 3-(2,3,4,6-tetra-O-acetyl-β-D-gluco-pyranosyloxy)-4-{[4-(2-carboxyethoxy)-2-methylphenyl]-methyl}-5-isopropyl-1H-pyrazole (0.2 g) in N,N-dimethyl-formamide (3 mL) were added 2-amino-2-methylpropionamide (47 mg), 1-hydroxybenzotriazole (50 mg), 1-ethyl-3-(3-dimethyl-aminopropyl)carbodiimide hydrochloride (118 mg) and triethylamine (0.13 mL), and the mixture was stirred at room temperature overnight. The reaction mixture was poured into water, and the resulting mixture was extracted with ethyl acetate. The extract was washed with water and brine, and dried over an hydrous sodium sulfate. The solvent was removed under reduced pressure, and the residue was purified by column chromatography on silica gel (eluent: dichloromethane/methanol=20/1-10/1) to give 3-(2,3,4,6-tetra-O-acetyl-β-D-glucopyranosyloxy)-4-[(4-{2-[1-carbamoyl-1-(methyl)ethylcarbamoyl]ethoxy}-2-methylphenyl)methyl]-5-isopropyl-1H-pyrazole (0.12 g). This material was dissolved in methanol (3 mL). To the solution was added sodium methoxide (28% methanol solution, 0.06 mL), and the mixture was stirred at room temperature for 1 hour. To the reaction mixture was added acetic acid (0.1 mL), and the resulting mixture was concentrated under reduced pressure. The residue was purified by solid phase extraction on ODS (washing solvent: distilled water, eluent: methanol) to give the title compound (80 mg).
