Synthesis
Under nitrogen protection, 2-nitro-3-methoxypyridine (32 g, 208 mmol) was dissolved in a solvent mixture of ethyl acetate (150 mL) and methanol (35 mL) and 10% palladium-carbon catalyst (1.5 g, 1.4 mmol) was added. After displacing the reaction system with hydrogen three times, the reaction mixture was stirred under hydrogen atmosphere for 3 hours. Upon completion of the reaction, the system was again displaced three times with nitrogen, the reaction mixture was filtered through a diatomaceous earth pad, and the filter cake was washed with ethyl acetate (2 x 35 mL). The filtrates were combined, concentrated under reduced pressure and dried under high vacuum to give 25.8 g of 2-amino-3-methoxypyridine (100% yield). The product was analyzed by LC-MS showing m/z: 125.0 (MH+); 1H NMR (300 MHz, CDCl3) δ: 7.66 (m, 1H), 6.90 (m, 1H), 6.61 (m, 2H), 4.64 (s, br, 2H), 3.83 (s, 3H).
References
[1] Patent: US2013/210818, 2013, A1. Location in patent: Paragraph 0380
[2] Patent: WO2009/115572, 2009, A2. Location in patent: Page/Page column 114-115
[3] Patent: WO2014/206903, 2014, A1. Location in patent: Page/Page column 15; 16
[4] Green Chemistry, 2017, vol. 19, # 3, p. 809 - 815
[5] Patent: WO2013/92739, 2013, A1. Location in patent: Page/Page column 16
