1-(4-Amino-3,5-dichlorophenyl)ethan-1-one → 3',5'-Dichloroacetophenone

Participants

Reaction Conditions

Reaction Steps

814 g (4 mol) of 4-acetyl-2,6-dichloroaniline, prepared according to patent DD 273,435 of the 15/11/1989, are recrystallised from a mixture of 1200 ml of concentrated hydrochloric acid and 5200 ml of concentrated acetic acid. After cooling to 0° C., a solution of 290 g (4.2 mol) of sodium nitrite in 770 ml of water is run in in a thin stream. After 2 h 30 at this temperature, the solution is run onto 2200 ml of a 50% solution of hypophosphorous acid in water at 5° C. At the end of the addition, the mixture is left to return to room temperature, 10 l of water are then added and the aqueous phase is extracted with dichloromethane. After drying of the separated organic phase, and concentration and distillation of the crude product, there are obtained 591 g (yield 70%, boiling point: 91-95° C. at 1 mm Hg) of (3,5-dichloro)phenyl-ethanone in the form of a pale yellow liquid.

Provenance & Evidence