Reaktion #74810

Reaktionsgleichung

2-cyano-4-methylpyridine

furan

ether

hydrochloric acid

butyl-lithium

→

2-(2-furoyl)-4-methylpyridine

Ausbeute 51.0%

Lösungsmittel

benzene

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.ADDITIONare slowly added under a nitrogen atmosphere
2. 2
   Sonstigeat -20° C
3. 3
   Sonstigeto reach room temperature
4. 4
   Temperaturto reflux for seven hours
5. 5
   workup.ADDITIONare added drop by drop
6. 6
   workup.ADDITIONUpon completion of the addition
7. 7
   Temperaturto reflux for two and a half hours
8. 8
   Temperaturis cooled
9. 9
   SonstigeThe organic layer is removed
10. 10
    Sonstigeby decanting
11. 11
    Waschenis washed with 6 N hydrochloric acid
12. 12
    Sonstigethe aqueous layers are collected
13. 13
    Sonstigethe residual ether is removed
14. 14
    workup.DISTILLATIONby distilling and once 100° C.
15. 15
    Temperaturto reflux for one and a half hours
16. 16
    Temperaturis cooled externally
17. 17
    workup.ADDITION50% sodium hydroxide is added until a basic pH
18. 18
    Extraktionthe resulting solution is extracted with chloroform
19. 19
    TrocknenAfter being dried once over anhydrous magnesium sulphate
20. 20
    Sonstigeevaporated to dryness
21. 21
    Sonstigethe organic layer is purified by chromatography on silica gel in a continuous flow column

Vorschrift

75 gr of freshly distilled furan dissolved in 180 ml of anhydrous ether are placed in a four-liter reactor and 800 ml of a 1,3 N ethereal solution of freshly prepared butyl-lithium are slowly added under a nitrogen atmosphere, keeping the temperature at -20° C. The reaction mixture is then allowed to reach room temperature, following which it is boiled to reflux for seven hours. It is then cooled to -20° C. and 116 gr of 2-cyano-4-methylpyridine dissolved in one liter of anhydrous benzene are added drop by drop. Upon completion of the addition, the mixture is boiled to reflux for two and a half hours, following which it is cooled and 6 N hydrochloric acid is carefully added until an acid pH is reached. The organic layer is removed by decanting, said layer is washed with 6 N hydrochloric acid, the aqueous layers are collected, the residual ether is removed by distilling and once 100° C. are reached the mixture is boiled to reflux for one and a half hours. Following this, the reactor is cooled externally, 50% sodium hydroxide is added until a basic pH is reached and the resulting solution is extracted with chloroform. After being dried once over anhydrous magnesium sulphate and evaporated to dryness, the organic layer is purified by chromatography on silica gel in a continuous flow column using benzene as eluent, providing 93 gr of 2-(2-furoyl)-4-methylpyridine (II) (Yield 51%). An analytical sample recrystallized from ether has a melting point of 111-2° C. Analysis calculated for C11H9NO2 : C: 70.58; H: 4.81; N: 7.48. Found: C: 70.48; H: 5.11; N: 7.20.

Quelle