5-Acetoxy-2-fluoropyridine (2.26 g, 14.6 mmol, from Step 8d) was used as raw material and dissolved in 20% aqueous NaOH (15 mL). The reaction mixture was stirred at room temperature for 1 hour. Subsequently, the reaction solution was neutralized with concentrated HCl. The aqueous phase was extracted with ethyl acetate. The organic phases were combined, dried with anhydrous MgSO4 and concentrated under reduced pressure to remove the solvent. Purification by silica gel column chromatography (eluent: CHCl3/MeOH, 98:2) afforded 1.31 g of the target product 2-fluoro-5-hydroxypyridine in 79% yield. Mass spectra (MS) m/z: 114 (M + H)+, 131 (M + NH4)+; 1H NMR (CDCl3, 300 MHz) δ 6.84 (dd, J = 1.85,5.14 Hz, 1H), 7.43 (m, 1H), 7.81 (t, J = 2.84 Hz, 1H).
