Sodium triacetoxyborohydride (477 mg, 2.25 mmol) and then acetic acid (99 μl, 1.73 mmol) were added to a suspension of 4-methyl-1-tetrahydro-2H-pyran-2-yl-1H-indazol-5-amine (400 mg, 1.73 mmol) and 8-benzyl-8-azabicyclo[3.2.1]octan-3-one (410 mg, 1.90 mmol) in 1,2-dichloroethane (5 ml), and the resulting mixture was stirred at room temperature for 1 day. The reaction mixture was poured into a saturated aqueous sodium hydrogencarbonate solution and then extracted with ethyl acetate. The extract solution was washed with a saturated aqueous sodium chloride solution, dried over sodium sulfate, and then distilled under reduced pressure to remove the solvent. The residue was purified by a silica gel column chromatography (eluent: chloroform/methanol=100/2) to obtain N-(8-benzyl-8-azabicyclo[3.2.1]oct-3-yl)-4-methyl-1-tetrahydro-2H-pyran-2-yl-1H-indazol-5-amine (283 mg, 38%).
