4-AMINO-3-BROMO-2-CHLOROPYRIDINE

14432-12-3

215364-85-5

General procedure for the synthesis of 3-bromo-2-chloropyridin-4-amine from 2-chloro-4-aminopyridine: N-bromosuccinimide (NBS, 2.77 g, 15.56 mmol) was added batchwise to a stirred solution of 2-chloropyridin-4-amine (17A, 2 g, 15.56 mmol) in acetic acid (20 mL) at 0 °C and under nitrogen protection. The reaction mixture was then stirred at room temperature for 1 hour. Upon completion of the reaction, the solvent was removed by distillation under reduced pressure and azeotropic distillation with ethanol was performed to further remove the residual solvent. The crude product was purified by silica gel column chromatography (using a 40 g RediSep column with a gradient elution using a petroleum ether solution of 10-20% ethyl acetate as eluent) to afford the target compound, 3-bromo-2-chloropyridin-4-amine (15B, 2 g, 9.64 mmol, 62.0% yield), as a white solid.LCMS analysis: m/z = 209.0 [M + H]+; retention time 0.84 min; condition B.