Hydrochloric Acid → Methyl 3-oxovalerate

51.7 g (0.2 mol) of acetoacetic acid methyl ester magnesium enolate in 750 ml of tetrahydrofuran was suspended under nitrogen, 24.3 g (0.24 mol) of triethylamine was added and 38.9 g (0.408 mol) of propionyl chloride was instilled in 15 minutes. The reaction mixture was refluxed for 2 hours, cooled with ice water and hydrolyzed with 285 ml of 1 N HCl. The phases were separated and the water phase was extracted with tert-butyl methyl ether. The organic phases were combined and 140 ml of 10 percent ammonia solution was added with vigorous stirring within 15 minutes. After 1 hour, the phases were separated, dried with sodium sulfate and concentrated by evaporation. The residue was distilled with a Spaltrohr column (split-tube column) at 100 mbars. There was a yield of 23.9 g of 3-oxovaleric acid methyl ester with a purity of 96.0 percent, corresponding to 44 percent of theory. The acetoacetic acid methyl ester separated as the first runnings was able to be used again. The yield thus increased, relative to reacted acetoacetic acid methyl ester, to 69 percent. The boiling point of the product was 109° to 111 C./100 mbars.

1. temperatureThe reaction mixture was refluxed for 2 hours
2. customThe phases were separated
3. extractionthe water phase was extracted with tert-butyl methyl ether
4. addition140 ml of 10 percent ammonia solution was added
5. waitAfter 1 hour
6. customthe phases were separated
7. dry with materialdried with sodium sulfate
8. concentrationconcentrated by evaporation
9. distillationThe residue was distilled with a Spaltrohr column (split-tube column) at 100 mbars
10. customThe acetoacetic acid methyl ester separated as the first runnings
11. customThe yield thus
12. temperatureincreased
13. customwas 109° to 111 C

ORD record

ord-f47853561b924953bd096ddc1b679f10

Source dataset

uspto-grants-1992_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05144057