Synthesis
General procedure for the synthesis of 4-amino-3-bromopyridine from 4-aminopyridine: To a mixture of 4-aminopyridine (20.0 g, 0.21 mol) and acetonitrile (300.0 mL) was added N-bromosuccinimide (NBS) (39.8 g, 0.22 mol) in batches at 0 °C, the reaction was to be carried out protected from light. Subsequently, the reaction mixture was stirred at room temperature for 24 hours. The progress of the reaction was monitored by thin layer chromatography (TLC) and after confirming the completion of the reaction, the mixture was cooled to room temperature and filtered. The filtrate was concentrated under reduced pressure and the residue was purified by fast column chromatography (silica gel as stationary phase and dichloromethane/methanol=20:1 as eluent) to afford the target compound 4-amino-3-bromopyridine (33.2 g, 91.4% yield) as a light yellow solid. Mass spectrum (ESI) m/z: 172.9 [M + H]+.
References
[1] European Journal of Medicinal Chemistry, 2016, vol. 120, p. 37 - 50
[2] Organic and Biomolecular Chemistry, 2017, vol. 15, # 15, p. 3216 - 3231
[3] Patent: US2003/22883, 2003, A1
[4] Journal of the American Chemical Society, 2012, vol. 134, # 31, p. 12928 - 12931
