Acetic Acid → 2-Ethyl-4-hydroxy-3-methylcyclopent-2-en-1-one

A mixed solution of 28.97 g of the 1-(5-methyl-2-furyl)propanol thus obtained, 0.394 g of 50% aqueous acetic acid, 0.394 g of a 23% (w/v) sodium hydroxide solution in 579.4 g of water was heated and refluxed at the constant pH of 5.70 to 5.85 for 38 hours. After the mixed solution was cooled to the room temperature, a 23% (w/v) sodium hydroxide solution was added to the mixed solution to adjust the pH of the solution to 8.0 to 8.2, and then refluxed for three hours. A 50% acetic acid solution was added to the refluxing solution to adjust the pH to 6.0 to 6.5. The reaction solution was then cooled to the room temperature, mixed with 300 g of sodium chloride, and extracted three times with 500 ml of diethyl ether. The combined ether layer was washed twice with a saturated sodium chloride solution and dried over anhydrous magnesium sulfate. After removal of the solvent under reduced pressure, the residue was distilled, and a distillate fraction of 157° to 162° C. at 19 mmHg was collected to yield 15 g of (RS)-4-hydroxy-3-methyl-2-ethylcyclopent-2-en-1-one. Yield 52% b.p.: 157°-162° C. (19 mmHg)

1. temperaturerefluxed at the constant pH of 5.70 to 5.85 for 38 hours
2. temperaturerefluxed for three hours
3. temperatureThe reaction solution was then cooled to the room temperature
4. extractionextracted three times with 500 ml of diethyl ether
5. washThe combined ether layer was washed twice with a saturated sodium chloride solution
6. dry with materialdried over anhydrous magnesium sulfate
7. customAfter removal of the solvent under reduced pressure
8. distillationthe residue was distilled
9. distillationa distillate fraction of 157° to 162° C. at 19 mmHg was collected

ORD record

ord-7d865cb594f044a28cc83e74df568551

Source dataset

uspto-grants-1997_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05672779