Bromotrifluoromethane → 3',4'-Dimethyl-2,2,2-trifluoroacetophenone

Beteiligte Stoffe

Reaktionsschritte

Under protective gas, 41 g (0.27 mol) of trifluoromethyl bromide are condensed into a solution of 42 g (0.25 mol) of 3,4-dimethylbenzoyl chloride in 150 ml of CH2Cl2 in a round-bottomed flask at about -70° C. A solution of 66.7 g (0.27 mol) of phosphorous acid trisdiethylamide in 50 ml of CH2Cl2 are then metered in at about -70° C., the first 90% of the solution being added rapidly and the last 10% of the solution being metered in slowly (during the course of about 2 hours). The mixture is subsequently stirred for one hour more at this temperature and then warmed to room temperature. After addition of the same volume of hexane, 2 phases are formed. After phase separation, the lower phase is carefully extracted using hexane; the combined hexane phases are concentrated and distilled under reduced pressure. 20.8 g (41% yield) of 1-(3,4-dimethylphenyl)- 2,2,2-trifluoroethan-1-one of b.p. 98°-99° C./22 mbar are obtained.

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