Sulfuric Acid → Diethyl (2,4-dichloro-5-fluoro-3-nitrobenzoyl)propanedioate

Beteiligte Stoffe

Reaktionsschritte

2.1 g of carbon tetrachloride are added to 10.1 g of magnesium filings in 21 ml of ethanol and, when the evolution of hydrogen has started, a mixture of 66.6 g of diethyl malonate, 40 ml of ethanol and 150 ml of toluene is added dropwise at 50°-60° C. The mixture is subsequently stirred at this temperature for 1 hour and cooled to -5° to -10° C. and a solution of 109.2 g of 2,4-dichloro-5-fluoro-3-nitro-benzoyl chloride in 50 ml of toluene is slowly added dropwise. The mixture is then stirred at 0° C. for 1 hour, brought to room temperature overnight and warmed at 40°-50° C. for a further 2 hours. A mixture of 160 ml of water and 10.4 ml of concentrated sulphuric acid is added to the reaction mixture, while cooling with ice, and the organic phase is separated off. The aqueous phase is extracted with toluene, the combined organic extract is washed with saturated sodium chloride solution and dried with sodium sulphate and the solvent is stripped off. 144.5 g of diethyl (2,4-dichloro-5-fluoro-3-nitro-benzoyl)-malonate are obtained as a crude product. After adding 200 ml of water and 0.6 g of 4-toluenesulphonic acid, this is heated under reflux for 3 hours, the mixture is extracted with methylene chloride, the extract is dried with sodium sulphate and the solvent is distilled off in vacuo. 118 g of substituted benzoylacetate are obtained as a crude product. It has a sufficient purity for further reactions.

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