5-Bromo-2-chloropyridine

Light yellow Cryst

5-Bromo-2-chloropyridine may be used in the preparation of following compounds:

• Amino-2-chloropyridine via palladium-catalyzed amination.
• 5-Bromo-2-fluoropyridine via halogen-exchange reaction using anhydrous potassium fluoride.
• 2-Chloro-5-(2,5-dimethoxyphenyl)pyridine via Suzuki coupling with 2,5-dimethoxyphenylboronic acid.

6-Chloro-pyridin-3-ylamine was dissolved slowly with constant stirring in 48% HBr solution (50 mL) at r.t. and then the solution was cooled to -10 °C. A solution of sodium nitrite in cold water was added dropwise at -10 °C with constant stirring over 2 h, followed by a solution of copper (I) bromide in 48% HBr dropwise. The mixture was then stirred at r.t. until complete. The mixture was neutralized with sodium carbonate and extracted with ethyl acetate. The organic phase was washed with brine, dried over sodium sulfate, and concentrated. The residue was purified by column chromatography on silica gel (60-120 mesh) eluting with 1% ethyl acetate/petroleum ether to afford 5- bromo-2-chloropyridine.

[1] Journal of Medicinal Chemistry, 2007, vol. 50, # 15, p. 3627 - 3644
[2] Patent: WO2008/62182, 2008, A1. Location in patent: Page/Page column 119
[3] Patent: WO2004/6922, 2004, A1. Location in patent: Page/Page column 53
[4] Zhurnal Russkago Fiziko-Khimicheskago Obshchestva, 1920, vol. 50, p. 476
[5] Chem. Zentralbl., 1923, vol. 94, # III, p. 1020