Sulfuric Acid → Ethyl 3-oxovalerate

Participants

Reaction Steps

A solution of diethyl malonate (80 g.) in ethanol (40 ml.) was added dropwise over 20 minutes to a mixture of magnesium (12.5 g.), carbontetrachloride (0.5 ml.) and ethanol (12.5 ml.) was stirred at room temperature for 10 minutes. Diethyl ether was added dropwise to the solution and refluxed under heating for 30 minutes. To the solution was added dropwise a solution of propionyl chloride (49 g.) in diethyl ether (50 ml.) under cooling over 10 minutes, and the mixture was refluxed under heating for 30 minutes. 20% sulfuric acid (200 ml.) was added to the solution, and the diethyl ether layer was separated, washed with 10% sulfuric acid and water successively, dried over magnesium sulfate and then filtered. The filtrate was evaporated in vacuo. To the oily residue was added β-naphthalene sulfonic acid hydrate (8 g.) and the mixture was heated at 200° C. for 1 hr. After cooling, diethyl ether (100 ml.) was added to the mixture and washed with 10% aqueous sodium carbonate (100 ml.) three times. The aqueous layer was extracted with diethyl ether (100 ml.) five times, and the extract was washed with water, dried over magnesium sulfate and then distilled under reduced pressure (24 mmHg). The distillate at 100° to 110° C. was collected and distilled again under reduced pressure (25 mmHg). The distillate at 97° to 99° C. was collected to give ethyl propionylacetate (19.8 g.).

Provenance & Evidence