Synthesis
1. Concentrated sulfuric acid (0.95 mL, 17.2 mmol, 0.5 eq.) was slowly added to a solution of 6-aminonicotinic acid (5.0 g, 34.4 mmol) in ethanol (50 mL). 2. The reaction mixture was heated and refluxed for 16 h. 3. Upon completion of the reaction the mixture was carefully poured into a concentrated aqueous solution of Na2CO3 to neutralize. 4. The aqueous phases were extracted three times using EtOAc. 5. The organic layers were combined, washed with saturated brine, dried over anhydrous Na2SO4, filtered, and concentrated under reduced pressure.6 The concentrated residue was dissolved in anhydrous THF (25 mL).7 Lithium aluminium hydride (2.68 g, 68.6 mmol, 3.0 eq.) was added slowly at -60 °C.8 The reaction mixture was gradually warmed to 0 °C, followed by refluxing for 1 h. The reaction was completed by cooling to room temperature and then refluxing for 1 h. The reaction was completed by cooling to room temperature. At the end of the reaction, the reaction was cooled to room temperature and quenched by the addition of water (1.5 mL) and 5N aqueous NaOH (1.5 mL). 10. The precipitate was removed by filtration, and the filtrate was concentrated under reduced pressure. 11. The residue was purified by fast column chromatography (eluent: EtOAc/MeOH 95:5) to afford the target product, 6-amino-3-pyridinemethanol (2.15 g, 72% yield). 12. The structure of the product was determined by 1.5 mL of fast column chromatography (eluent: EtOAc/MeOH 95:5). The product structure was confirmed by 1H NMR and mass spectrometry: 1H NMR (400 MHz, d6-DMSO): δ= 7.82 (d, J = 1.7 Hz, 1H), 7.32 (dd, J = 8.3/2.5 Hz, 1H), 6.40 (dd, J = 9.3/1.0 Hz, 1H), 5.77 (br s, 2H), 4.88 ( t, J = 5.5 Hz), 4.88 (br s, 2H), 4.88 (t, J = 5.5 Hz, 4.88), 4.88 ( t, J = 5.5 Hz, 1H), 4.27 (d, J = 5.5 Hz, 2H). MS (ES+): 125 (M + H)+.
References
[1] Patent: WO2008/74752, 2008, A2. Location in patent: Page/Page column 27-28
[2] Patent: EP1798221, 2007, A1. Location in patent: Page/Page column 32
[3] Patent: EP1956013, 2008, A1. Location in patent: Page/Page column 30-31
[4] Patent: US2007/99930, 2007, A1. Location in patent: Page/Page column 42
[5] Patent: WO2013/13817, 2013, A1
