Synthesis
To a solution of 2-Amino-5-chloro-3-nitropyridine (10.0 g, 57.6 mmol) in HBr [(31.0 mL (100%), 286.4 mmol)], sodium nitrite (13.8 g, 199.9 mmol) was added dropwise. To the stirred solution, Br2 (10.0 mL, 197.1 mmol)in water was added and stirred at room temperature for 1 h. The reaction mixture was basified with NaHCO3 solution (PH=7), extracted with ethyl acetate, washed with water, and dried over anhydrous Na2SO4. The solvent was removed under vacuum to yield 2-Bromo-5-chloro-3-nitropyridine (10.0 g, 73.0%) as a yellow solid.
