p-Toluenesulfonic acid → Ethyl 2,4-dichloro-5-fluorobenzoylacetate

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Reaction Steps

0.15 g of p-toluenesulphonic acid is added to an emulsion of 34.9 g of crude diethyl 2,4-dichloro-5-fluoro-benzoylmalonate (3) in 50 ml of water. The mixture is heated at the boiling point for 3 hours, while stirring thoroughly, the cooled emulsion is extracted several times with methylene chloride, the combined CH2Cl2 solutions are washed once with saturated NaCl solution and dried with Na2SO4 and the solvent is distilled off in vacuo. Fractionation of the residue in vacuo gives 21.8 g of ethyl 2,4-dichloro-5-fluoro-benzoylacetate (4) of boiling point 127° to 142° C./0.09 mbar.

Provenance & Evidence