Reaktion #55093

Reaktionsgleichung

sodium chloroacetate

NaOH

thiourea

3,4-dimethoxybenzylchloride

→

3,4-Dimethoxybenzylthio-acetic acid

Ausbeute 69.0%

Lösungsmittel

water

water

Reaktionsbedingungen

Aufarbeitung

1. 1
   Sonstigeequipped with a magnetic stirrer and a condenser
2. 2
   TemperaturThe mixture is heated to 50°-60° C.
3. 3
   TemperaturThe reactants are heated
4. 4
   Temperaturto reflux
5. 5
   Temperaturboiling is maintained for 15 mins
6. 6
   TemperaturThereafter the mixture is cooled
7. 7
   TemperaturHeating
8. 8
   Temperaturunder reflux
9. 9
   Temperaturthe mixture is cooled
10. 10
    TemperaturThe whole is then heated
11. 11
    Temperaturunder reflux for 30 minutes
12. 12
    Temperaturcooled
13. 13
    Filtrationfiltered
14. 14
    SonstigeAfter recrystallisation from toluene, 28.7 g of 3,4-dimethoxybenzylthio-acetic acid
15. 15
    Sonstigeare obtained

Vorschrift

13.07 g (0.172 mol) of thiourea and 86 ml of water are introduced into a 1 liter 3-necked flask equipped with a magnetic stirrer and a condenser. The mixture is heated to 50°-60° C. and 32 g (0.172 mol) of 3,4-dimethoxybenzylchloride are added in a single operation. The reactants are heated to reflux and boiling is maintained for 15 mins; the solution becomes limpid. Thereafter the mixture is cooled and a solution of 27.52 g (0.688 mol) of NaOH in 43 ml of water is introduced dropwise at about 60° C. Heating under reflux is again carried out for 30 minutes, the mixture is cooled and a solution of sodium chloroacetate (obtained by neutralising 22.76 g of chloroacetic acid in 172 ml of water with 20.23 g of NaHCO3) is added dropwise at 60°-70° C. The whole is then heated under reflux for 30 minutes, cooled, filtered and then acidified with 3 N HCl. After recrystallisation from toluene, 28.7 g of 3,4-dimethoxybenzylthio-acetic acid are obtained. Yield: 69%. Instantaneous melting point: 94° C.

Quelle