1,1,1-Triacetoxy-1,1-dihydro-1,2-benziodoxol-3(1H)-one (221 mg, 0.526 mmol) was added to a solution of 1-[2-(1-adamantyl)ethyl]-3-[3-hydroxy-3-(4-pyridyl)propyl]-1-pentylurea (100 mg, 0.234 mmol) in anhydrous dichloromethane (2 ml) under ice-cooling, the temperature was raised to room temperature, and the mixture was stirred for one hour. The reaction mixture was cooled with ice again, ethyl acetate (10 ml), a saturated aqueous sodium sulfite solution (5 ml) and a saturated aqueous sodium hydrogencarbonate solution (5 ml) were added to the reaction mixture, and the whole was stirred for 15 minutes. The reaction mixture was distributed with ethyl acetate (50 ml) and water (10 ml), and the organic layer was washed with a saturated aqueous sodium sulfite solution (5 ml), a saturated aqueous sodium hydrogencarbonate solution (5 ml) and a saturated aqueous sodium chloride solution (25 ml) successively. The organic layer was dried over anhydrous magnesium sulfate, and the solvent was evaporated under reduced pressure to give 87.3 mg (87.8%) of the titled compound as colorless crystals.
