Reaktion #215035

Reaktionsgleichung

water

Diethyl malonate

sodium

3,3-Dimethyl-1-bromoallene

→

ethyl 3,3-dimethyl-2-ethoxycarbonylpent-4-ynoate

Lösungsmittel

ethanol

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturwas refluxed for 3 hours
2. 2
   SonstigeThe ethanolic solution obtained
3. 3
   Extraktionthe mixture extracted with chloroform (3×200 ml.)
4. 4
   Trocknendried with anhydrous sodium sulphate
5. 5
   Sonstigeevaporated
6. 6
   workup.DISTILLATIONthe residual oil distilled under reduced pressure

Vorschrift

Diethyl malonate (34.8 g.) was added to a solution of sodium (5.0 g.) in ethanol (500 ml.) and the mixture stirred for a few minutes. 3,3-Dimethyl-1-bromoallene (32.0 g.) was then added dropwise at the ambient temperature after which the mixture was refluxed for 3 hours. The ethanolic solution obtained was poured into an excess of water and the mixture extracted with chloroform (3×200 ml.). The extracts were combined, dried with anhydrous sodium sulphate and evaporated and the residual oil distilled under reduced pressure to yield ethyl 3,3-dimethyl-2-ethoxycarbonylpent-4-ynoate, as an oil b.p. 56°-60°/0.1 mm. Hg.

Quelle