Oxygen → Coolact HK

To a 500 ml reaction vessel, 70.0 g (453.8 mmol) of isopulegol and 140 ml of methanol were added and ozone generated in an oxygen stream by silent discharge was introduced into the reaction solution while the temperature of the solution was being kept between from 15° C. to 23° C. After 10 hours, disappearance of the raw material, isopulegol was confirmed by the gas chromatogram. The reaction solution obtained was cooled in an ice bath and then added into an excess amount of an aqueous sodium sulfite solution at a temperature of 30° C. or lower, followed by stirring for 2 hours. The solution was extracted with toluene. The toluene solution obtained was sequentially washed with dilute hydrochloric acid, an aqueous sodium carbonate solution, an aqueous ammonium chloride solution and brine, and was dried over anhydrous sodium sulfate. After filtration, the solvent was removed by evaporation under a reduced pressure. The mixture obtained was crystallized by adding 350 ml of heptane, and the crystal obtained was washed with 50 ml of cold heptane followed by drying under vacuum to obtain 53.08 g (yield: 74.9%) of the titled compound as a colorless needle crystal.