Sulfuric Acid → Ethyl 3-oxovalerate

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.).

1. temperaturerefluxed
2. temperatureunder heating for 30 minutes
3. temperatureunder cooling over 10 minutes
4. temperaturethe mixture was refluxed
5. temperatureunder heating for 30 minutes
6. customthe diethyl ether layer was separated
7. washwashed with 10% sulfuric acid and water successively
8. dry with materialdried over magnesium sulfate
9. filtrationfiltered
10. customThe filtrate was evaporated in vacuo
11. additionTo the oily residue was added β-naphthalene sulfonic acid hydrate (8 g.)
12. temperaturethe mixture was heated at 200° C. for 1 hr
13. temperatureAfter cooling
14. additiondiethyl ether (100 ml.) was added to the mixture
15. washwashed with 10% aqueous sodium carbonate (100 ml.) three times
16. extractionThe aqueous layer was extracted with diethyl ether (100 ml.) five times
17. washthe extract was washed with water
18. dry with materialdried over magnesium sulfate
19. distillationdistilled under reduced pressure (24 mmHg)
20. distillationThe distillate at 100° to 110° C. was collected
21. distillationdistilled again under reduced pressure (25 mmHg)
22. distillationThe distillate at 97° to 99° C. was collected

ORD record

ord-f56d1b75fe534334ac3bc218a3b9adb4

Source dataset

uspto-grants-1987_10

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04703046