Sulfuric Acid → Diethyl 2-(2,4-dichloro-5-fluorobenzoyl)malonate

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Reaction Steps

24.3 g of magnesium turnings were suspended in 50 ml of anhydrous ethanol. 5 ml of carbon tetrachloride were added and, when the reaction had started, a mixture of 160 g of diethyl malonate, 100 ml of absolute ethanol and 400 ml of anhydrous ether was added dropwise, a vigorous reflux being observed. After the reaction had ceased, the mixture was heated at the boil for a further 2 hours and was cooled with dry ice/acetone at 315° C. to -10° C. and a solution of 227.5 g of 2,4-dichloro-5-fluoro-benzoyl chloride in 100 ml of absolute ether was slowly added dropwise at this temperature. The mixture was stirred for 1 hour at 0° C. to -5° C. and was allowed to reach room temperature overnight, and a mixture of 400 ml of ice-water and 25 ml of concentrated sulphuric acid was allowed to run in while cooling with ice. The phases were separated and were extracted twice with ether. The combined ether solutions were washed with saturated NaCl solution and dried with Na2SO4, and the solvent was stripped off in vacuo. 349.5 g of diethyl 2,4-dichloro-5-fluoro-benzoyl-malonate were obtained as the crude product.

Provenance & Evidence