General procedure for the synthesis of 4-methoxy-2-methylpyridine from 2-methyl-4-methoxypyridine nitrogen oxide: 4-methoxy-2-methylpyridine 1-oxide (500 mg, 3.59 mmol) was dissolved in acetic acid (10 mL) at room temperature, followed by addition of iron powder (602 mg, 10.79 mmol). The reaction mixture was stirred at 120°C for 2 h. The progress of the reaction was monitored by thin layer chromatography (TLC) until the reaction was completed. After completion of the reaction, the mixture was cooled to room temperature and filtered through a diatomaceous earth pad to remove solid impurities. The filtrate was diluted with distilled water (50 mL) and subsequently extracted with ethyl acetate (3 x 50 mL). The organic layers were combined, washed sequentially with distilled water (100 mL) and saturated brine (100 mL), dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure to give 4-methoxy-2-methylpyridine as a brown oil. Yield: 250 mg (56%). The structure of the product was confirmed by 1H NMR (400 MHz, DMSO-d6) and mass spectrometry (ESI+): 1H NMR δ 8.23 (d, J = 5.6 Hz, 1H), 6.82 (s, 1H), 6.76 (d, J = 2.2 Hz, 1H), 3.79 (s, 3H), 2.39 (s, 3H); MS (ESI+) m/z 124.23 [M + H]+.
