Reaktion #55184

Reaktionsgleichung

3-(2',4'-difluoro-4-biphenylyl)-3-hydroxybutyric acid ethyl ester

HCl

SOCl2

→

3-(2',4'-difluoro-4-biphenylyl)butyric acid

Lösungsmittel

dichloromethane

Reaktionsbedingungen

Aufarbeitung

1. 1
   TemperaturThe mixture is warmed to 50° for 2 hours
2. 2
   Sonstigesolvent is removed
3. 3
   workup.DISSOLUTIONThe residue, 3'(2',4'-difluoro-4-biphenylyl)-3-chlorobutyric acid ethyl ester, is dissolved in 100 ml
4. 4
   Sonstigeat 25°
5. 5
   FiltrationThe precipitate is filtered off
6. 6
   workup.ADDITIONof water is added to the filtrate
7. 7
   TemperaturThe mixture is heated
8. 8
   Temperaturunder reflux for 2 hours
9. 9
   Sonstigeevaporated
10. 10
    workup.DISSOLUTIONthe residue is dissolved in water

Vorschrift

A solution of 3.2 g. of 3-(2',4'-difluoro-4-biphenylyl)-3-hydroxybutyric acid ethyl ester in 10 ml. of dichloromethane is saturated with dry HCl gas and 1 ml. of SOCl2 is added. The mixture is warmed to 50° for 2 hours and solvent is removed. The residue, 3'(2',4'-difluoro-4-biphenylyl)-3-chlorobutyric acid ethyl ester, is dissolved in 100 ml. of methanol and hydrogenated on 100 mg. of platinum oxide under normal pressure at 25°. The precipitate is filtered off. A solution of 0.4 g. of NaOH in 5 ml. of water is added to the filtrate. The mixture is heated under reflux for 2 hours and evaporated and the residue is dissolved in water and worked up in the customary manner to give 3-(2',4'-difluoro-4-biphenylyl)butyric acid, m.p. 109°-110°.

Quelle