Reaktion #44980

Reaktionsgleichung

diisopropylamine

n-butyllithium n-hexane

4-chloropyridine

sodium hydroxide

dry ice acetone

→

4-chloronicotinic acid hydrochloride

Lösungsmittel

tetrahydrofuran

dry ice

tetrahydrofuran

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturcooling
2. 2
   Temperatursame cooling conditions
3. 3
   workup.STIRRINGThe mixture is then stirred for 20 minutes under the
4. 4
   Temperatursame cooling conditions
5. 5
   SonstigeThe resulting reaction solution
6. 6
   TemperaturThe reaction solution is cooled with ice
7. 7
   Einengenfollowed by concentration under reduced pressure
8. 8
   workup.DISSOLUTIONThe resulting residue is dissolved in water
9. 9
   Waschenwashed with dichloromethane
10. 10
    TemperaturThe aqueous layer is cooled with ice
11. 11
    FiltrationThe precipitates are collected by filtration
12. 12
    Sonstigedried

Vorschrift

To a solution of diisopropylamine (20.0 g) in tetrahydrofuran (200 ml) is added dropwise 1.6 M n-butyllithium/n-hexane solution under ice-cooling. The mixture is then stirred for 30 minutes under the same cooling conditions. The reaction mixture is cooled with dry ice-acetone, and thereto is added dropwise a solution of 4-chloropyridine (20.4 g) in tetrahydrofuran (100 ml). The mixture is then stirred for 20 minutes under the same cooling conditions. The resulting reaction solution is poured in crushed dry ice in a portion and then warmed to room temperature. The reaction solution is cooled with ice and basified by addition of sodium hydroxide, followed by concentration under reduced pressure. The resulting residue is dissolved in water and washed with dichloromethane. The aqueous layer is cooled with ice and acidified with conc. hydrochloric acid. The precipitates are collected by filtration and dried to give 4-chloronicotinic acid hydrochloride (21.4 g).

Quelle