Diethyl Malonate → Ethyl pivaloylacetate

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Reaction Steps

Ethyl pivaloylacetate was prepared from diethyl malonate in the following manner. Diethyl malonate (64 g, 0.4 mol) was dissolved in 350 ml of a mixture of xylene isomers. A solution of sodium ethoxide, prepared by dissolving sodium (9.66 g, 0.42 g at) in absolute ethanol (150 ml), was then added with stirring at ambient temperature. Ethanol was removed by distillation. After the mixture was cooled to 50° C., pivaloylchloride (53 g, 0.4 mol) was added with stirring over a period of one hour and the resulting slurry stirred for a further hour. The mixture obtained was then filtered to remove sodium chloride and the filtrate added to dry sodium ethoxide, which had been prepared by dissolving sodium (9.29 g; 0.4 g at) in 250 ml of absolute ethanol and evaporating to dryness. After stirring for 90 minutes at 50° C., the mixture was acidified with dilute hydrochloric acid and the organic phase separated and dried over anhydrous magnesium sulphate. Evaporation of the solvent in a rotary evaporator followed by vacuum distillation afforded essentially pure ethyl pivaloylacetate product as a colorless liquid (b.p. 167° C. at 65 mbar). Structure of the product was confirmed with NMR analysis. The product yield, determined by GLC, was 0.343 mol (86%).

Provenance & Evidence