Potassium Carbonate → 5-Ethenyl-6-fluoropyridin-3-ol

To a stirred solution of the 5-acetoxy-2-fluoro-3-ethenylpyridine from b above (1.40 g, 7.70 mmol) in MeOH (50 mL) was added K2CO3 (0.53 g, 3.90 mmol). The reaction mixture was allowed to stir at room temperature 24 h. The solvent was evaporated and the residue was diluted with Et2O (100 mL) and water (100 mL). The phases were separated and the aqueous phase was neutralized (pH=7) by the addition of 1 N aqueous HCl, and extracted with Et2O (2×100 mL). The combined ethereal extracts were washed with brine (50 mL), dried (MgSO4), and the solvent was evaporated. The crude product was purified by column chromatography (silica gel; EtOAc/hexane, 4:6) to afford the desired material as an off-white solid (0.81 g, 76%): 1H NMR (CDCl3, 300 MHz) δ 5.50 (d, J=11.0 Hz, 1H), 5.87 (d, J=17.5 Hz, 1H), 6.75 (m, 1H), 7.72 (dd, J=3.0, 5.0 Hz, 1H), 7.69 (m, 1H); MS (CI/NH3) m/z 140 (M+H)+, 157 (M+NH4)+.