Synthesis
Bromine (2.8 g, 17.5 mmol) was added slowly dropwise to an aqueous solution (21 mL) of sodium hydroxide (2.1 g, 52.5 mmol) at -5 °C. Subsequently, 2-bromo-4,6-dimethylpyridine-3-carboxamide (3.19 g, 14 mmol) was added all at once. The reaction mixture was first stirred at 0 °C for 1 h, then warmed up to 70 °C and continued stirring for 1 h. The reaction was carried out at 0 °C for 1 h. The reaction mixture was then cooled to 70 °C. After completion of the reaction, the mixture was cooled to room temperature. Extraction was carried out with dichloromethane and the organic layer was washed with saturated brine and dried with anhydrous sodium sulfate. After filtration, the filtrate was concentrated and the residue was purified by silica gel column chromatography (eluent: hexane-ethyl acetate, 2:1) to afford the target product 3-amino-2-bromo-4,6-dimethylpyridine (2.8 g, 100% yield) as a light yellow solid.
References
[1] Bioorganic and Medicinal Chemistry Letters, 2012, vol. 22, # 15, p. 5093 - 5097
[2] European Journal of Medicinal Chemistry, 2012, vol. 55, p. 395 - 408,14
[3] European Journal of Medicinal Chemistry, 2012, vol. 55, p. 395 - 408
[4] Organic Letters, 2008, vol. 10, # 21, p. 4895 - 4898
[5] Journal of Organic Chemistry, 2010, vol. 75, # 3, p. 716 - 725
