[CH:1]1([CH2:4][O:5][C:6]2[CH:11]=[C:10]([F:12])[C:9]([O:13]COC)=[CH:8][N:7]=2)[CH2:3][CH2:2]1.Cl.C(=O)([O-])O.[Na+]>C1COCC1>[CH:1]1([CH2:4][O:5][C:6]2[N:7]=[CH:8][C:9]([OH:13])=[C:10]([F:12])[CH:11]=2)[CH2:2][CH2:3]1To a solution of 2-(cyclopropylmethoxy)-5-(methoxymethoxy)pyridine (789 mg, 3.77 mmol) obtained in Reference Example 266 in THF (10 mL) was added 1.6 M n-butyllithium-hexane solution (3.10 mL, 4.90 mmol) at −78° C., and the mixture was stirred at the same temperature for 30 min. To this solution was added N-fluoro-N-(phenylsulfonyl)benzenesulfonamide (1.78 g, 5.66 mmol), and the mixture was stirred at room temperature for 10 min. The reaction was quenched with water, and the mixture was extracted with ethyl acetate. The extract was dried over anhydrous magnesium sulfate. The solvent was evaporated under reduced pressure and the obtained residue was purified by silica gel column chromatography (hexane:ethyl acetate=9:1 to 7:3) to give 2-(cyclopropylmethoxy)-4-fluoro-5-(methoxymethoxy)pyridine as an oil. The 2-(cyclopropylmethoxy)-4-fluoro-5-(methoxymethoxy)pyridine was dissolved in THF (10 mL), 6N hydrochloric acid (2.90 mL, 17.4 mmol) was added thereto and the mixture was stirred at 50° C. for 1 hr. The reaction mixture was neutralized with saturated aqueous sodium hydrogen carbonate, and the mixture was extracted twice with ethyl acetate. The combined organic layer was dried over anhydrous magnesium sulfate. The solvent was evaporated under reduced pressure and the obtained residue was purified by silica gel column chromatography (hexane:ethyl acetate=17:3 to 1:1) to give the title compound (279 mg, yield 40%) as a white solid.
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