Sulfuric Acid → 1-(2,4-Dichlorophenyl)prop-2-en-1-one

Participants

Reaction Conditions

Reaction Steps

73.5 g (362 mmol) of the compound from Example 185A in 2.21 of dichloromethane were mixed with 105 g (1.21 mol) of activated manganese dioxide and heated under reflux for 20 h. A further 105 g (1.21 mol) of activated manganese dioxide was added in each case after 2 and 4 h. Filtration with suction through kieselguhr, washing with dichloromethane and concentration resulted in 57.0 g of a mixture of the title compound and the compound from Example 185A. 47.7 g (162 mmol) of potassium dichromate were added to 47.0 g of this mixture in 329 ml of 10% strength sulfuric acid, occasionally cooling at 15-20° C., and the mixture was stirred for 1.5 h. This was followed by addition of 400 ml of ethyl acetate, neutralization by adding sodium bicarbonate, filtration through kieselguhr, washing with ethyl acetate, separation of the phases, drying of the organic phase and concentration. The crude product was purified by column chromatography on silica gel (mobile phase: cyclohexane/ethyl acetate 6/1) to result in 17.8 g (55%) of the title compound.

Provenance & Evidence