Sulfuric Acid → Ethyl 2,4-difluoro-3-methyl-β-oxobenzenepropanoate

Participants

Reaction Steps

8 ml of ethnol and 1 ml of carbon tetrachloride are added to 3.6 g of magnesium turnings. After initiation of the reaction, a mixture of 22.2 g of ethyl malonate, 15 ml of ethanol and 60 ml of toluene are added at 50° C. The mixture is warmed for 1 hour at 50°-60° C. and then cooled to -5°--10° C. A solution of 25.7 g of 2,4-difluoro-3-methyl-benzoyl chloride (from 2,4-difluoro-3-methylbenzoic acid and thionyl chloride) in 15 ml of toluene is added dropwise at this temperature. The mixture is then allowed to come to room temperature. After standing overnight, a mixture of 60 ml of water and 10 ml of H2SO4 is added dropwise. The phases are separated, and the organic phase is washed with water, dried and concentrated. 50 ml of water and 2.0 g of p-toluenesulphonic acid are added to the oily residue. The mixture is refluxed for 4.5 hours, the phases are separated, and the organic phase is dried and concentrated in vacuo. 33.9 g of the title compound remain as a crude oil.

Provenance & Evidence