反应详情

0.04 g of p-toluenetoluenesulphonic acid is added to an emulsion of 34.7 g of crude diethyl (2,4-dichloro-3,6-difluorobenzoyl)-malonate in 40 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 sodium chloride solution and dried with Na2SO4 and the solvent is distilled off in vacuo. Fractionation of the residue (33.9 g) in vacuo gives 13.9 g of ethyl (2,4-dichloro-3,6-difluorobenzoyl)-acetate of boiling point 110°-115° C./0.05 mbar, nD25 : 1,5241.

1. temperatureThe mixture is heated at the boiling point for 3 hours
2. extractionthe cooled emulsion is extracted several times with methylene chloride
3. washthe combined CH2Cl2 solutions are washed once with saturated sodium chloride solution
4. dry with materialdried with Na2SO4
5. distillationthe solvent is distilled off in vacuo