Synthesis
To a stirred dichloromethane (DCM) solution of 6-methylpyridine-3-carboxylic acid (0.3 g, 2 mmol) was added ammonium chloride (0.7 g, 13 mmol), triethylamine (TEA, 2.7 mL, 19 mmol), and propylphosphoric anhydride (T3P, 4 mL, 6.5 mmol) sequentially at 0 °C. The reaction mixture was stirred at room temperature for 16 hours. Upon completion of the reaction, the reaction was quenched by the addition of saturated sodium bicarbonate (NaHCO3) solution and the reaction mixture was extracted with dichloromethane (DCM). The organic layer was separated, washed with saturated brine, dried over anhydrous sodium sulfate (Na2SO4) and concentrated under reduced pressure. The crude product was purified by Combiflash rapid chromatography system using 10% methanol (MeOH) in dichloromethane (DCM) solution as eluent to give white solid 6-methylnicotinamide (0.1 g, 33.6% yield). The product was confirmed by 1H NMR (DMSO-d6, 400 MHz): δ2.48 (s, 3H), 7.30 (d, J=8Hz, 1H), 7.44 (bs, 1H), 8.02 (bs, 1H), 8.07 (dd, J=2.4 Hz, J=2.4 Hz, 1H), 8.88 (s, 1H); mass spectra (ESI) m/z 137.1 ([M+H]+); HPLC analysis showed a purity of 98.97% at 264 nm.
References
[1] Bioorganic and Medicinal Chemistry Letters, 2018, vol. 28, # 5, p. 922 - 925
[2] Journal of Chemical Research, Miniprint, 1987, # 9, p. 2360 - 2384
