1,3-Dibromo-5-chlorobenzene

626-39-1

14862-52-3

General procedure for the synthesis of 1,3-dibromo-5-chlorobenzene from 1,3,5-tribromobenzene: 1,3,5-tribromobenzene (9.44 g, 30 mmol) was dissolved in 120 mL of ethyl ether and cooled to -78 °C in a dry ice/acetone bath. Over 10 min, n-butyllithium (13.2 mL of a 2.5 M hexane solution, 33 mmol) was added slowly and dropwise. The reaction mixture was continued to be stirred at -78 °C for 10 min, followed by the addition of hexachloroethane (7.15 g, 30.2 mmol) in batches over 3 min. After addition, the reaction mixture was stirred at -78 °C for 15 minutes, then brought to room temperature and stirred for 3.2 hours. Upon completion of the reaction, the mixture was transferred to a dispensing funnel and partitioned by adding 100 mL of water and 100 mL of ethyl acetate. The aqueous layer was separated and extracted with another 100 mL of ethyl acetate. The organic layers were combined, dried with anhydrous magnesium sulfate, filtered and concentrated under reduced pressure to give the light brown solid product 1,3-dibromo-5-chlorobenzene (7.72 g, 95% yield). The product was characterized by 1H NMR (CDCl3, 300 MHz): δ 7.57 (t, 1H), 7.47 (d, 2H).