Reaktion #4267

Reaktionsgleichung

diethyl methylmalonate

propargyl bromide

sodium bromide

→

Diethyl 2-methyl-2-propargyl-malonate

Lösungsmittel

Reaktionsbedingungen

Aufarbeitung

1. 1
   SonstigeAt 35° to 40°
2. 2
   workup.STIRRINGthe mixture is stirred for a further hour
3. 3
   Sonstigeat 45° C
4. 4
   TemperaturThe mixture is refluxed for a further 2 hours
5. 5
   Sonstigeis separated by suction
6. 6
   Filtrationfiltering
7. 7
   Sonstigethe filtrate is substantially evaporated in vacuo
8. 8
   workup.STIRRINGThe residue is stirred into ice water
9. 9
   Extraktionthe aqueous solution is extracted several times with ether
10. 10
    SonstigeThe combined organic phases are dried
11. 11
    Sonstigeevaporated to dryness in vacuo
12. 12
    SonstigeThe resulting oil is used in the next stage without any further purification

Vorschrift

At 35° to 40° to C., with stirring, 174 g (1.0 ml) of diethyl methylmalonate are added dropwise to an alkoxide solution (prepared from 23 g of sodium and 800 ml of absolute ethanol), the mixture is stirred for a further hour and then at 45° C. 130.8 g (1.1 mol) of propargyl bromide are added dropwise. The mixture is refluxed for a further 2 hours. After cooling the precipitated sodium bromide is separated by suction filtering and the filtrate is substantially evaporated in vacuo. The residue is stirred into ice water and the aqueous solution is extracted several times with ether. The combined organic phases are dried and evaporated to dryness in vacuo. The resulting oil is used in the next stage without any further purification.

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