Sulfuric Acid → 2-Chloro-5-bromo-6-fluorobenzamide

Participants

Reaction Conditions

Reaction Steps

Concentrated sulfuric acid (15 mL) was placed in a 100 mL 3-neck flask equipped with an internal thermometer and then heated to 55° C. 3-Bromo-2-fluoro-6-chlorobenzonitrile (11.0 g, 47 mmol) was added portion-wise to the acid with stirring maintaining the temperature above 50° C. The dark solution was heated at 65° C. for 24 hours then cooled to room temperature and poured over ice and cautiously neutralized with concentrated ammonium hydroxide. The mixture was extracted with two portions of ethyl acetate and the combined organic layers dried over Na2SO4 (with charcoal). Filtration and concentration gave 3-bromo-2-fluoro-6-chlorobenzamide (11.5 g, 45.5 mmol) as a light orange solid: mp 157-158° C., 1H NMR (CDCl3): δ 7.54 (t, 1H), 7.14 (dd, 1H), 6.03 (bs, 1H) 5.81 (bs, 1H).

Provenance & Evidence