C([N:3]([CH2:6]C)CC)C.[C:8]([OH:12])([CH3:11])([CH3:10])[CH3:9].C1C=CC(P(N=[N+]=[N-])(C2C=CC=CC=2)=[O:20])=CC=1.[F:30][C:31]1[C:32]([O:40][CH3:41])=[N:33][CH:34]=[C:35]([CH:39]=1)C(O)=O>O.C1(C)C=CC=CC=1>[F:30][C:31]1[CH:39]=[C:35]([NH:3][C:6](=[O:20])[O:12][C:8]([CH3:11])([CH3:10])[CH3:9])[CH:34]=[N:33][C:32]=1[O:40][CH3:41]Triethylamine (267 μl), tert-butanol (230 μl), and DPPA (413 μl) were added to a toluene (5 ml) solution containing 5-fluoro-6-methoxynicotinic acid (275 mg), followed by reflux for 3 hours. The reaction solution was adjusted to room temperature and water was added, followed by extraction with ethyl acetate. Next, the organic layers were washed with saturated saline and dried over anhydrous sodium sulfate and the solvent was distilled away under reduced pressure. Then, the obtained residue was purified by silica gel chromatography (n-hexane:ethyl acetate=10:1 to 3:1). Colorless oily matter of tert-butyl (5-fluoro-6-methoxypyridin-3-yl)carbamate (279 mg) was thus obtained.
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