Reacción #55093

Ecuación de reacción

sodium chloroacetate

NaOH

thiourea

3,4-dimethoxybenzylchloride

→

3,4-Dimethoxybenzylthio-acetic acid

Rendimiento 69.0%

Disolventes

water

water

Condiciones de reacción

Tratamiento posterior

1. 1
   Otroequipped with a magnetic stirrer and a condenser
2. 2
   TemperaturaThe mixture is heated to 50°-60° C.
3. 3
   TemperaturaThe reactants are heated
4. 4
   Temperaturato reflux
5. 5
   Temperaturaboiling is maintained for 15 mins
6. 6
   TemperaturaThereafter the mixture is cooled
7. 7
   TemperaturaHeating
8. 8
   Temperaturaunder reflux
9. 9
   Temperaturathe mixture is cooled
10. 10
    TemperaturaThe whole is then heated
11. 11
    Temperaturaunder reflux for 30 minutes
12. 12
    Temperaturacooled
13. 13
    Filtraciónfiltered
14. 14
    OtroAfter recrystallisation from toluene, 28.7 g of 3,4-dimethoxybenzylthio-acetic acid
15. 15
    Otroare obtained

Procedimiento

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.

Fuente