Synthesis
General procedure for the synthesis of 5-amino-1-methylpyridin-2(1H)-one using 1-methyl-5-nitro-2(1H)-pyridone as starting material: to a stirred solution of 1-methyl-5-nitro-2(1H)-pyridinone (113 mg, 0.33 mmol) in ethanol (3 mL) at 0 °C was added sequentially reduced iron powder (129 mg, 2.30 mmol) and 2N hydrochloric acid (0.07 mL). The reaction mixture was heated to reflux for 2 hours and then thermally filtered. The resulting brown solid was washed several times with ethanol. The ethanol phases were combined and concentrated under reduced pressure and the residue was dissolved in ethyl acetate (15 mL) and washed with 1.5N aqueous sodium carbonate solution (20 mL). After separating the organic and aqueous phases, the aqueous phase was then back-extracted with ethyl acetate (15 mL x 3). All organic phases were combined, dried with anhydrous magnesium sulfate, filtered and concentrated under reduced pressure to afford the target product 5-amino-1-methylpyridin-2(1H)-one (205 mg, about 100% yield).
References
[1] Patent: WO2009/154769, 2009, A1. Location in patent: Page/Page column 47
[2] Patent: WO2014/191894, 2014, A1. Location in patent: Page/Page column 89
[3] Patent: WO2012/48258, 2012, A2. Location in patent: Page/Page column 32-33
[4] Heterocycles, 1990, vol. 31, # 12, p. 2201 - 2204
[5] Australian Journal of Chemistry, 1984, vol. 37, p. 1625 - 1630
