Hydrochloric Acid → (1R)-1-[(2R)-2-(2,4-difluorophenyl)-2-oxiranyl]ethanol

[(1R )-1-[(2R )-2-(2,4-Difluorophenyl)-2-oxiranyl]ethyl]3,5-dinitrobenzoate (50 g) was dissolved in two liters of methanol and, at room temperature, 255 ml of 1N sodium hydroxide was added dropwise thereinto. The reaction solution was stirred at room temperature for one hour and neutralized with 127 ml of 1N hydrochloric acid. Methanol was distilled off under reduced pressure, then one liter of ethyl acetate and 200 ml of water were added to the residue, and the mixture was extracted with ethyl acetate. The organic extract was washed with 200 ml of a saturated aqueous solution of sodium chloride, dried over magnesium sulfate and distilled off under reduced pressure. The residue was purified by silica gel chromatography (eluent: ethyl acetate/hexane=1/3) to give 25 g of (1R)-1-[(2R)-2-(2,4-difluorophenyl)-2-oxiranyl]ethanol as a pale yellow oil.