Synthesis
General procedure for the synthesis of 2-amino-3-bromo-5-chloropyridine from 2-amino-5-chloropyridine: In a 50L round bottom three-necked flask, a mixed solvent of DMF and ethanol (1:1.8 by volume, total 18.7L) was added, a thermometer and a reflux condenser were installed, and a magnetic stirrer was started. Sequentially, 4986.6 g of 2-amino-5-chloropyridine and 17336.3 g of N-bromosuccinimide were added, the temperature was raised to 85 °C and the reaction was stirred for 3.5 hours. The progress of the reaction was monitored by GC and TLC and after confirming the completion of the reaction, the solvent was removed using a rotary evaporator. The crude product obtained was recrystallized with hexane to give the pure 2-amino-3-bromo-5-chloropyridine. After drying, the calculated yield was 70.4% and purity was 99.15%.
References
[1] Patent: US2014/315888, 2014, A1. Location in patent: Paragraph 0620-0622
[2] Journal of Medicinal Chemistry, 2018, vol. 61, # 7, p. 2949 - 2961
[3] Patent: US2009/156603, 2009, A1. Location in patent: Page/Page column 46
[4] Patent: EP1202994, 2004, B1. Location in patent: Page 18
[5] European Journal of Medicinal Chemistry, 2018, vol. 157, p. 115 - 126
