Synthesis
The general procedure for the synthesis of 5-bromo-6-(trifluoromethyl)-2-aminopyridine from 2-amino-6-(trifluoromethyl)pyridine was as follows: to a solution of 6-(trifluoromethyl)pyridin-2-amine (600 mg, 3.7 mmol) in methanol (10 mL) was added N-bromosuccinimide (NBS, 659 mg, 3.7 mmol) in batches at 0 °C. The reaction mixture was stirred at room temperature overnight. Upon completion of the reaction, the reaction mixture was concentrated under reduced pressure and the residue was purified by column chromatography (eluent: petroleum ether/ethyl acetate = 4:1) to afford 5-bromo-6-trifluoromethyl-2-aminopyridine (650 mg, 73.1% yield) as a white solid.The LC-MS analysis showed a retention time of 1.33 min and a molecular ion peak (MH+) of 241.
References
[1] Patent: WO2016/44792, 2016, A1. Location in patent: Page/Page column 173
[2] Bioorganic and Medicinal Chemistry Letters, 2012, vol. 22, # 1, p. 527 - 531
[3] Patent: WO2017/1926, 2017, A2. Location in patent: Paragraph 00139
[4] Patent: CN105541792, 2016, A. Location in patent: Paragraph 0242; 0243; 0244
