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

Participants

Reaction Steps

Magnesium turnings (0.77 g) and carbon tetrachloride (0.4 ml) was added to absolute ethanol (5.3 ml). To the stirring suspension was added a solution of diethyl malonate (4.89 g) and absolute ethanol (8.5 ml) in toluene (21.3 ml) dropwise during 40 minutes at 20° to 40° C. The mixture was stirred at 50° to 60° C. for 2 hours, and then cooled in an acetone-dry ice bath. A solution of 2,3-dichloro-4,5-difluorobenzoyl chloride (6.00 g) in anhydrous toluene (7.1 ml) was added dropwise to the resulting solution at -18° to -13° C. during 10 minutes. The mixture was warmed gradually to room temperature during 2 hours and then mixed with ice water (17 ml) containing concentrated sulfuric acid (1.1 ml). The resulting organic layer was collected and the water layer was extracted with toluene. The combined organic layer was washed with water, dried over anhydrous sodium sulfate and then concentrated to give the title compound (9.68 g) as pale yellow oil.

Provenance & Evidence