IPEA (0.68 ml) and BOPCl (496 mg) were added to a solution of 5-chloro-2-cyclohexyl-valeric acid (285 mg) and tert-butyl carbazate (215 mg) in methylene chloride (2.5 ml), and the reaction solution was stirred at room temperature for 5.5 hours. Ethyl acetate and water were added to the reaction solution, and the organic layer was separated. The organic layer was sequentially washed with 1 N hydrochloric acid, water, a saturated sodium bicarbonate solution and brine, dried over anhydrous magnesium sulfate and then concentrated under reduced pressure. The resulting residue was purified by silica gel column chromatography (elution solvent: heptane-ethyl acetate system) to obtain 156 mg of the title compound. The property values of the compound are as follows.
