Synthesis
The general procedure for the synthesis of 2-chloro-3-amino-6-methoxypyridine using 2-chloro-6-methoxy-3-nitropyridine as starting material was as follows: tin(II) chloride dihydrate (6 g, 26.52 mmol) was added to a solution of 2-chloro-6-methoxy-3-nitropyridine (1 g, 5.30 mmol) in ethyl acetate (15 mL), and the resulting suspension was heated at 70 °C with stirring for 1 hour. The resulting suspension was heated with stirring for 1 hour at 70°C. Upon completion of the reaction, the mixture was cooled to room temperature and the pH was adjusted to 9-10 with saturated aqueous sodium carbonate solution, followed by extraction with ethyl acetate (3 x 50 mL). The organic phases were combined, dried with anhydrous magnesium sulfate and concentrated under reduced pressure to give the crude product. The crude product was purified by silica gel column chromatography with ethyl acetate:heptane (3:7, v/v) as eluent to afford the target compound 2-chloro-3-amino-6-methoxypyridine as a light yellow oil (600 mg, 72% yield). The product was confirmed by mass spectrometry (ESI), m/z: 159 ([M+H]+).
References
[1] Journal of Organic Chemistry, 2011, vol. 76, # 23, p. 9841 - 9844
[2] Organic Letters, 2016, vol. 18, # 11, p. 2774 - 2776
[3] Patent: WO2007/39563, 2007, A1. Location in patent: Page/Page column 26
[4] Patent: US2007/112019, 2007, A1. Location in patent: Page/Page column 13/2
[5] Patent: US2003/236287, 2003, A1. Location in patent: Page 40
