60% Sodium hydride (45.3 mg, 1.13 mmol) was added to a mixed solution of 2-hydroxypyridine (86 mg, 0.91 mmol) in 1,2-dimethoxyethane (2 ml) and DMF (1 mL) at room temperature. After stirring at room temperature for 5 min, lithium bromide (131 mg, 1.51 mmol) was added at room temperature. After stirring for 10 min, to the reaction mixture was added a solution of tert-butyl (6S,7R)-7-(4-chloro-3-fluorophenyl)-6-{[(methylsulfonyl)oxy]methyl}-1,4-oxazepane-4-carboxylate (331 mg, 0.76 mmol) in 1,2-dimethoxyethane (2 mL). The reaction mixture was stirred at 80° C. overnight. To the reaction mixture was added water, and the mixture was extracted with ethyl acetate. The extract was washed with brine, and dried over anhydrous sodium sulfate. The solvent was evaporated under reduced pressure. The residue was purified by silica gel column chromatography to give the title compound (267 mg, 0.611 mmol, 81%).
