Ethyl Acetate → 1-Cyclopropyl-butane-1,3-dione

Temperature

60 °C

To a stirring solution of THF (100 mL) was added potassium tert-butoxide (5.60 g, 49.5 mmol), followed by a mixture of cyclopropyl methyl ketone (3.27 mL, 33 mmol) and ethyl acetate (9.69 mL, 99 mmol) in 30 mL THF at 35° C., via addition funnel over a 25 min period. The contents were heated and stirred at 60° C. After 3 h, the contents were removed from heating, and allowed to cool to room temperature. The reaction mixture was carefully diluted with 30 mL 2N HCl and stirred for 10 min. The mixture was extracted with diethyl ether (3×50 mL), and the combined organic layers washed with brine (1×50 mL). The organic layer was dried over MgSO4, filtered, and concentrated in vacuo. Purification by chromatography on silica gel (eluent: 0 to 15% EtOAc in hexanes) with good separation afforded 1-cyclopropyl-1,3-butanedione as a light yellow colored oil, 3.9 g in ˜75% purity (residual solvent), for an overall yield of 70%. 1H NMR (400 MHz, CDCl3) δ ppm 0.89-0.96 (m, 2H), 1.09-1.15 (m, 2H), 1.59-1.69 (m, 1H), 2.04 (s, 3H), 5.63 (s, 1H), 15.5-16.0 (br s, 1H).

1. temperatureThe contents were heated
2. customthe contents were removed
3. temperaturefrom heating
4. temperatureto cool to room temperature
5. additionThe reaction mixture was carefully diluted with 30 mL 2N HCl
6. stirringstirred for 10 min
7. extractionThe mixture was extracted with diethyl ether (3×50 mL)
8. washthe combined organic layers washed with brine (1×50 mL)
9. dry with materialThe organic layer was dried over MgSO4
10. filtrationfiltered
11. concentrationconcentrated in vacuo
12. customPurification by chromatography on silica gel (eluent: 0 to 15% EtOAc in hexanes)
13. customwith good separation

ORD record

ord-d9594ddde7564648902ce95154eb423a

Source dataset

uspto-grants-2016_01

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09242962B2