反应详情

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 3N HCl. After recrystallisation from toluene, 28.7 g of 3,4-dimethoxybenzylthio-acetic acid are obtained. Yield: 69%. Instantaneous melting point: 94° C.

1. customequipped with a magnetic stirrer and a condenser
2. temperatureThe mixture is heated to 50°-60° C.
3. temperature-- The reactants are heated
4. temperatureto reflux
5. temperatureboiling is maintained for 15 mins
6. temperatureThereafter the mixture is cooled
7. temperatureHeating
8. temperatureunder reflux
9. temperaturethe mixture is cooled
10. temperatureThe whole is then heated
11. temperatureunder reflux for 30 minutes
12. temperaturecooled
13. filtrationfiltered
14. customAfter recrystallisation from toluene, 28.7 g of 3,4-dimethoxybenzylthio-acetic acid
15. customare obtained