Acetic Anhydride → 5-Bromo-6-chloropyridin-3-yl acetate

Participants

Reaction Conditions

Reaction Steps

To a stirred mixture of 5-bromo-6-chloropyridin-3-amine (7.57 g, 36.5 mmol) in tetrafluoroboric acid (70 mL, 536 mmol, 48 wt. % solution in water) at 0° C. was added sodium nitrite (2.64 g, 38.3 mmol) in water (70 mL) slowly over 10 min. The reaction mixture was stirred at 0° C. for 1 h. The reaction mixture was filtered and washed with water. The resulting solid was dissolved in acetic anhydride (70 mL, 742 mmol) and stirred at 70° C. for 1 h. The reaction mixture was cooled to room temperature, diluted with EtOAc, washed with water, washed with sat. sodium chloride, dried over magnesium sulfate, filtered, and concentrated. The resulting crude product was purified by silica gel chromatography to give 5-bromo-6-chloropyridin-3-yl acetate. MS (ESI, pos. ion) m/z: 249.9 and 251.9 (M+1).

Provenance & Evidence