Synthesis
General procedure for the synthesis of 2-Boc amine-4-bromopyridine from 2-amino-4-bromopyridine and di-tert-butyl dicarbonate: To a solution of 4-bromopyridin-2-amine (519 mg) in anhydrous THF (15 mL) was slowly added bis(trimethylmethylsilyl)amide (1 M solution in hexane, 6 mL) at -5 °C and the reaction mixture was stirred. After maintaining this temperature for 10 minutes, di-tert-butyl dicarbonate (654 mg) was added and the reaction mixture was transferred to room temperature to continue stirring for 1 hour. Upon completion of the reaction, the reaction was quenched by the addition of saturated ammonium chloride solution (20 mL) and the mixture was extracted with EtOAc. The organic layers were combined, washed sequentially with water and brine, dried over anhydrous sodium sulfate, and concentrated under reduced pressure to remove the solvent to afford the target product 2-Boc amine-4-bromopyridine in 96% yield.
References
[1] Patent: US2014/194443, 2014, A1. Location in patent: Paragraph 0541-0542
[2] Patent: WO2014/108337, 2014, A1. Location in patent: Page/Page column 69
[3] Patent: WO2016/124508, 2016, A1. Location in patent: Page/Page column 39
[4] Journal of Medicinal Chemistry, 2017, vol. 60, # 13, p. 5613 - 5637
[5] Patent: CN104744433, 2016, B. Location in patent: Paragraph 0027; 0028
