Reaktion #64651

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
   SonstigeThe mixture was partitioned between water and ether
5. 5
   Sonstigethe organic phase was separated
6. 6
   Sonstigedried
7. 7
   Sonstigethe ether was evaporated
8. 8
   workup.ADDITIONThe residue was treated with pyridine (26 mL), piperidine (1.22 g) and paraformaldehyde (3.56 g)
9. 9
   TemperaturThe mixture was heated in an oil bath (130°) for 90 minutes
10. 10
    Temperaturcooled
11. 11
    workup.ADDITIONwater (440 mL) was added
12. 12
    ExtraktionThe mixture was extracted 3 times with n-hexane (150 mL)
13. 13
    WaschenThe combined organic phases were washed successively with water, 1N HCl, water, saturated NaHCO3 solution and brine
14. 14
    TrocknenThe organic solution was dried (MgSO4)
15. 15
    Sonstigeevaporated

Vorschrift

A mixture of 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 solution was stirred at room temperature overnight, then concentrated by evaporation. Water (14 mL) was added and then the mixture was acidified in an ice bath with concentrated hydrochloric acid (12.6 mL). The mixture was partitioned between water and ether; the organic phase was separated, dried and the ether was evaporated. The residue was treated with pyridine (26 mL), piperidine (1.22 g) and paraformaldehyde (3.56 g). The mixture was heated in an oil bath (130°) for 90 minutes, then cooled, and water (440 mL) was added. The mixture was extracted 3 times with n-hexane (150 mL). The combined organic phases were washed successively with water, 1N HCl, water, saturated NaHCO3 solution and brine. The organic solution was dried (MgSO4) and evaporated to give the title compound as colorless oil (26 g, 85 % yield). 1H NMR: 300MHz spectrum consistent with proposed structure.

Quelle