The general procedure for the synthesis of 1-methyl-6-oxo-pyridine-3-carboxamide from ethyl 1-methyl-6-oxo-1,6-dihydropyridine-3-carboxylate was as follows: ethyl 1-methyl-6-oxo-1,6-dihydropyridine-3-carboxylate (0.2 g, 1.01 mmol) was dissolved in methanol-ammonia solution (10.0 mL), and the reaction was stirred for 16 hours at 70 °C. The reaction process was monitored by thin layer chromatography (TLC) [Expanding agent: 5% methanol-dichloromethane (v/v)]. After completion of the reaction, the reaction mixture was concentrated under reduced pressure to give the crude product. The crude product was ground with ether (10.0 mL) and filtered through a Büchner funnel and dried under vacuum to afford 1-methyl-6-oxopyridine-3-carboxamide as a white solid (15.0 g, 82% yield). The structure of the product was confirmed by 1H NMR (DMSO-d6, 400 MHz) and mass spectrometry (ESI): 1H NMR δ 3.44 (s, 3H), 6.35 (d, J = 9.2 Hz, 1H), 7.18 (bs, 1H), 7.65 (bs, 1H), 7.82 (dd, J = 2.4 Hz, J = 9.6 Hz, 1H), 8.66 (dd, J = 2.4 Hz, 1H); MS (ESI) m/z 153.0 (M + H)+; HPLC purity (254 nm) was 99%.
