Hydrochloric Acid → 3-Bromo-4-chlorobenzaldehyde

A solution of 10.7 g of 3-bromo-4-chloro-N-methoxy-N-methylbenzamide in 100 ml of anhydrous tetrahydrofuran was added dropwise to 43 ml of a 1M solution of lithium aluminium hydride in tetrahydrofuran at below 5° C., and stirred for 1 hour. 100 ml of saturated ammonium chloride solution was then added cautiously followed by 100 ml of a 1M solution of hydrochloric acid and the mixture was extracted twice with 400 ml of diethyl ether. The combined organic extracts were dried over anhydrous sodium sulphate and concentrated under reduced pressure to give 6.8 g of 3-bromo-4-chlorobenzaldehyde as a pale yellow solid.