Reaktion #65022

Reaktionsgleichung

KOH

benzylmalonic acid diethyl ester

→

title compound

Ausbeute 85.5%

ethyl α-methylenebenzenepropanoate

Ausbeute 85.5%

Lösungsmittel

ethanol

ethanol

Reaktionsbedingungen

Aufarbeitung

1. 1
   Einengenconcentrated by evaporation
2. 2
   workup.ADDITIONwater (14 mL) was added
3. 3
   Sonstigethe mixture was acidified in an ice bath with concentrated hydrochloric acid (12.6 mL)
4. 4
   SonstigePartitioning between water and ether
5. 5
   Sonstigethe organic phase was dried
6. 6
   workup.DISTILLATIONthe ether was distilled off
7. 7
   workup.ADDITIONThen, pyridine (26 mL), piperidine (1.22 g) and paraformaldehyde (3.56 g) were added to the residue
8. 8
   TemperaturThe mixture was heated in an oil bath (130° ) for 90 minutes
9. 9
   Temperaturcooled
10. 10
    workup.ADDITIONwater (440 mL) were added
11. 11
    Extraktionextraction
12. 12
    WaschenThe combined organic phases were washed with water, 1N HCl, water, saturated NaHCO3 solution and brine
13. 13
    TrocknenThe solution was dried (MgSO4)
14. 14
    Sonstigeevaporated

Vorschrift

A mixture of KOH (8.5 g) in ethanol (100 mL) was added at room temperature to benzylmalonic acid diethyl ester (40 g) in ethanol (80 mL) and the whole was stirred at room temperature overnight, then concentrated by evaporation, thereafter water (14 mL) was added and then the mixture was acidified in an ice bath with concentrated hydrochloric acid (12.6 mL). Partitioning between water and ether was carried out, the organic phase was dried and the ether was distilled off. Then, pyridine (26 mL), piperidine (1.22 g) and paraformaldehyde (3.56 g) were added to the residue. The mixture was heated in an oil bath (130° ) for 90 minutes, cooled, water (440 mL) were added and extraction was carried out 3 times with n-hexane (150 mL). The combined organic phases were washed with water, 1N HCl, water, saturated NaHCO3 solution and brine. The solution was dried (MgSO4) and evaporated to give the title compound as colourless oil (26 g, 85% yield). 1H NMR: 300 MHz spectrum consistent with proposed structure.

Quelle