3.6 mg (7.6 μmol equivalents) of 2,2-dimethyl-5-[(4-methoxymethoxymethyl-2-nitro-1H-imidazol-1-yl)methyl]-5-(p-toluenesulfonyloxymethyl)-1,3-dioxane was dissolved in 1 mL of acetonitrile, 17 mg (34.5 μmol equivalents) of Kryptofix 222 (trade name, Merck), 5.8 mg (100 μmol equivalents) of potassium fluoride, and 1.8 mg (23 μmol equivalents) of potassium carbonate were added thereto, and the mixture was refluxed while heating for 3 hours. After completion of the reaction, water was added, and the mixture was extracted three times with chloroform. The combined chloroform layers were dried with anhydrous sodium sulfate and then concentrated under vacuum. The obtained crude product was purified by silica gel column chromatography (eluent: hexane/ethyl acetate (v/v)=1/1). 1 mL of 1 mol/L hydrochloric acid was added dropwise to a fraction thus obtained, and the mixture was heated to 80° C. in an oil bath and then stirred for 50 minutes. After completion of the reaction, the mixture was concentrated under vacuum to give a trace amount of 1-(2,2-dihydroxymethyl-3-fluoropropyl)-4-hydroxymethyl-2-nitroimidazole.
