Sulfuric Acid → Diethyl 2-chloro-3-methyl-4,5-difluorobenzoylmalonate

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Reaction Steps

Separately, metallic magnesium (0.38 g) is suspended in anhydrous ethanol (0.8 ml) and thereto is added a few drops in carbon tetrachloride. When the reaction is started, a mixture of diethyl malonate (2.3 ml), anhydorus ethanol (1.5 ml) and anhydrous toluene (6 ml) is added portionwise at 50°-60° C. Thereto is added dropwise a solution of the above 2-chloro-4,5-difluoro-3-methylbenzoyl chloride (3.3 g) in anhydrous toluene (5 ml) at 0° C. After the addition, the mixture is stirred at room temperature for 30 minutes. To the raction mixture is added a mixture of conc. sulfuric acid (0.4 ml) and water (8 ml) and the mixture is extracted with diethyl ether. The extract is dried over magnesium sulfate and the solvent is then distilled off to give diethyl 2-chloro-3-methyl-4,5-difluorobenzoylmalonate (5.1 g).

Provenance & Evidence