Sulfuric Acid → 1,3-Diethyl 2-(2,3,4,5-tetrafluorobenzoyl)propanedioate

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

20.1 g of magnesium chips are suspended in 40 ml of anhydrous ethanol. 4 ml of carbon tetrachloride are added and, when the reaction has started, a mixture of 132.2 g of diethyl malonate, 80 ml of absolute ethanol and 320 ml of anhydrous toluene are added dropwise at 50°-60° C. When the reaction has subsided, the mixture is heated at 60° C. for a further 2 hours and cooled to -5° C. to -10° C. with dry ice/acetone, and a solution of 175.5 g of 2,3,4,5-tetrafluorobenzoyl chloride in 100 ml of absolute toluene is slowly added dropwise at this temperature. The mixture is stirred at 0° C. to -5° C. for 1 hour and is allowed to come to room temperature overnight, and a mixture of 350 ml of ice-wter and 50 ml of concentrated sulphuric acid is run in, while cooling with ice. The phases are separated and the aqueous phase is after-extracted twice with toluene. The combined toluene solutions are washed with saturated sodium chloride solution, and dried with sodium sulphate and the solvent is stripped off in vacuo. 284.8 g of diethyl 2,3,4,5-tetrafluoro-benzoyl-malonate are obtained as the crude product.

Herkunft & Nachweise