General procedure for the synthesis of 5-methoxypyridine-2-aldehyde from 5-fluoropyridine-2-aldehyde and sodium methanol: 5-fluoropyridine-2-aldehyde (450 mg, 3.60 mmol) and sodium methanol (291 mg, 5.40 mmol) were dissolved in methanol (15 mL), and the reaction was stirred at 55 °C overnight. After completion of the reaction, the reaction mixture was filtered and the filter cake was washed with methanol. The filtrate was concentrated under reduced pressure to give the crude product. The crude product was purified by ISCO medium pressure liquid chromatography (MPLC) system using 30-45% ethyl acetate/hexane as eluent to afford 5-methoxypyridin-2-aldehyde as colorless oil (326 mg, 66.1% yield).1H NMR (CDCl3) δ 9.93 (s, 1H), 8.37 (d, 1H), 7.90 (d, 1H), 7.24 (d, 1H), 7.24 (d, 1H), 7.30 (d, 1H). 1H), 7.24 (dd, 1H), 3.89 (s, 3H).
