Gamma-Butyrolactone → 3-Dimethylaminomethylenedihydrofuran-2-one
Reaktionsgleichung
[C:1]1(=[O:6])[O:5][CH2:4][CH2:3][CH2:2]1.[CH3:7][N:8]([CH:10](N(C)C)N(C)C)[CH3:9]>>[CH3:7][N:8]([CH:10]=[C:2]1[CH2:3][CH2:4][O:5][C:1]1=[O:6])[CH3:9]Komponenten
Reaktionsbedingungen
- Temperatur
- 75 °C
Versuchsvorschrift
A mixture of γ-butyrolactone (1 mol) and tris(dimethylamino)methane (1.5 mol) is stirred under dry nitrogen at 75° C. for 2 days to give 3-[(dimethylamino)methylene]dihydro-2(3H)-furanone. A solution containing 3-[(dimethylamino)methylene]dihydro-2(3H)-furanone (1 mol), n-butanethiol (1.1 mol) and para-toluenesulfonic acid (1 mol) in benzene is heated at reflux overnight to give upon aqueous work-up 3-[(butylthio)methylene]dihydro-2(3H)-furanone. After a solution of 3-[(butylthio)methylene]dihydro-2(3H)-furanone (1 mol) in anhydrous diethyl ether is added to a solution of lithium di-n-butylcuprate (1.1 mol) in diethyl ether at -78° C., the resulting mixture is stirred at -78° C. for an additional 0.5 hours and then quenched with methanol. Work-up affords 3-ethylidenedihydro-2(3H)-furanone. Freshly prepared W-2 Raney nickel (about 3 parts) is deactivated by refluxing in benzene for 1 hour, whereupon 3-ethylidenedihydro-2(3H)-furanone is added and the mixture is heated at reflux under nitrogen for 24-48 hours; the reaction is monitored by thin layer chromatography. After complete washing of the Raney nickel with hot benzene, the title compound is obtained.
Quellen und Nachweise
- ORD-Eintrag
- ord-560a0c24bf3d4fa4b4252783bf074ded
- Quelldatensatz
- uspto-grants-1991_11
- Patentnummer
- US05066663
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