Diethyl methylmalonate → HCID 89392410, compound

Participants

Reaction Steps

In a three-necked round-bottom flask 9.50 g (0.413 mol) of sodium metal was dissolved in 260 ml of dry ethanol. To the resulting solution 72.0 g (0.413 mol) of diethyl methylmalonate was added. This mixture was stirred for 15 min, then 5-bromo-2-methylbenzyl chloride prepared above was added by vigorous stirring at such a rate as to maintain gentle reflux. This mixture was refluxed for an additional 2 h and then cooled to room temperature. A solution of 85 g of KOH in 250 ml of water was added. The resulting mixture was refluxed for 4 h to saponificate the ester formed. Ethanol and water were distilled off until temperature reached 95° C., and 1000 ml of water and then 12 M HCl (to pH 1) were added to the residue. The precipitated substituted methylmalonic acid was filtered off, washed with 3×100 ml of water, and then decarboxylated at 180° C. to give 3-(5-bromo-2-methylphenyl)-2-methylpropanoic. A mixture of this acid and 105 ml of SOCl2 was stirred at room temperature for 24 hours. After evaporation of an excess of thionyl chloride, the residue was distilled in vacuum to give 85.3 g (75% from 5-bromo-2-methylbenzaldehyde) 3-(5-bromo-2-methylphenyl)-2-methylpropanoyl chloride, b.p. 115° C./1 mm Hg.

Provenance & Evidence