Reaktion #1795600

Reaktionsgleichung

2-(4-methylphenyl)-3-cyano-4,5-dihydrothiophene

bromine

hydrobromic acid

→

2-(4-methylphenyl)-3-cyanothiophene

Ausbeute 64.4%

Lösungsmittel

carbon tetrachloride

carbon tetrachloride

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturthe mixture is heated
2. 2
   Temperaturto reflux and, after two hours
3. 3
   workup.ADDITIONare added dropwise
4. 4
   TemperaturRefluxing
5. 5
   Sonstigethe solvent is evaporated off under vacuum
6. 6
   workup.ADDITION28 g of potassium tert-butylate are added
7. 7
   TemperaturThe mixture is heated
8. 8
   Temperaturto reflux for one hour
9. 9
   Temperaturcooled
10. 10
    workup.ADDITIONtreated with water and sodium chloride
11. 11
    Extraktionextracted with ether
12. 12
    SonstigeThe organic phase is evaporated under vacuum

Vorschrift

49.9 g of 2-(4-methylphenyl)-3-cyano-4,5-dihydrothiophene, prepared in D), are dissolved in 200 ml of carbon tetrachloride, the mixture is heated to reflux and, after two hours, 11 g of bromine, dissolved in 200 ml of carbon tetrachloride, are added dropwise. Refluxing is continued until evolution of hydrobromic acid has ceased, and the solvent is evaporated off under vacuum. The residue is taken up in 200 ml of anhydrous tetrahydrofuran, and 28 g of potassium tert-butylate are added. The mixture is heated to reflux for one hour, then cooled and treated with water and sodium chloride and extracted with ether. The organic phase is evaporated under vacuum to give 31.8 g of 2-(4-methylphenyl)-3-cyanothiophene in the form of an oil, which is used without further purification for the next step.

Quelle