Synthesis
Step 1. Synthesis of 6-bromo-2-Boc-aminopyridine: To a solution of dichloromethane (24 mL) containing 6-bromopyridin-2-amine (3 g, 17.34 mmol), triethylamine (3.14 mL, 22.54 mmol), and DMAP (0.424 g, 3.47 mmol) was slowly added a solution of dichloromethane (6 mL) containing di-tert-butyl dicarbonate (4.83 mL, 20.81 mmol). 20.81 mmol) to a solution of dichloromethane (6 mL). The reaction mixture was stirred at room temperature for about 24 hours. Upon completion of the reaction, the reaction mixture was diluted with water, saturated saline and ethyl acetate. The aqueous layer was separated and extracted with ethyl acetate. The organic layers were combined, dried over anhydrous sodium sulfate and concentrated under reduced pressure. The residue was purified by column chromatography to give 6-bromo-2-tert-butoxycarbonylaminopyridine as a white solid. Yield: 1.67 g. LCMS (m/z): 274.9 [M+H]+; Retention time: 0.54 min (major peak), 0.95 min.
References
[1] Patent: WO2012/101066, 2012, A1. Location in patent: Page/Page column 77
[2] Journal of Medicinal Chemistry, 2010, vol. 53, # 24, p. 8709 - 8715
[3] Patent: WO2017/205536, 2017, A2. Location in patent: Page/Page column 193; 194
[4] Patent: WO2004/113331, 2004, A1. Location in patent: Page 68
[5] Patent: WO2006/53791, 2006, A2. Location in patent: Page/Page column 39-40
