Reaktion #357375

Reaktionsgleichung

2′-methoxyacetophenone

ethyl cyanoacetate

ethyl cyanoacetate

ammonium acetate

→

2-Cyano-3-(2-methoxyphenyl)-but-2-enoic acid ethyl ester

Lösungsmittel

benzene

acetic acid

acetic acid

ethyl acetate

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturis heated
2. 2
   Temperaturto reflux in a Dean-Stark apparatus
3. 3
   workup.WAITAfter an additional 10 hours
4. 4
   Waschenwashed with water (240 mL), brine (40 mL)
5. 5
   Trocknendried (Na2SO4)
6. 6
   FiltrationAfter filtering
7. 7
   Einengenthe extract is concentrated in vacuo
8. 8
   workup.ADDITIONthe desired product, as a mixture of E and Z-isomers
9. 9
   Sonstigeis isolated by column chromatography on silica gel
10. 10
    Wascheneluting with 5% ethyl acetate in petroleum ether

Vorschrift

A mixture of 2′-methoxyacetophenone (50 mmol), ethyl cyanoacetate (50 mmol), acetic acid (1.14 mL) ammonium acetate (400 mg), and benzene (50 mL) is heated to reflux in a Dean-Stark apparatus. After approximately 10 hours, additional ethyl cyanoacetate (50 mmol), acetic acid (1.14 mL), and ammonium acetate (400 mg) are added. After an additional 10 hours, the reaction is cooled to room temperature, diluted with ethyl acetate (30 mL), washed with water (240 mL), brine (40 mL), and dried (Na2SO4). After filtering, the extract is concentrated in vacuo and the desired product, as a mixture of E and Z-isomers, is isolated by column chromatography on silica gel, eluting with 5% ethyl acetate in petroleum ether.

Quelle