Triethylamine (0.789 ml, 5.69 mmol) was added to a solution of 1-tetrahydro-2H-pyran-2-yl-1H-indazol-5-amine (1.04 g, 4.79 mmol) and benzyl 4-(chlorosulfonyl)-1-piperidinecarboxylate (1.5 g, 4.74 mmol) in methylene chloride (50 ml) at 0° C. and stirred at 0° C. for 30 minutes and then at room temperature for 15 hours. The reaction solution was poured into water and extracted with chloroform. The organic layer was dried over anhydrous magnesium sulfate and distilled under reduced pressure to remove the solvent, and the resulting residue was purified by a silica gel column chromatography (eluent: chloroform/ethyl acetate=3/1) to obtain benzyl 4-{[(1-tetrahydro-2H-pyran-2-yl-1H-indazol-5-yl)amino]sulfonyl}-1-piperidinecarboxylate (1.32 g, 56%).
