반응 #55093

반응 방정식

sodium chloroacetate

NaOH

thiourea

3,4-dimethoxybenzylchloride

→

3,4-Dimethoxybenzylthio-acetic acid

수율 69.0%

용매

water

water

반응 조건

후처리

1. 1
   기타equipped with a magnetic stirrer and a condenser
2. 2
   온도The mixture is heated to 50°-60° C.
3. 3
   온도The reactants are heated
4. 4
   온도to reflux
5. 5
   온도boiling is maintained for 15 mins
6. 6
   온도Thereafter the mixture is cooled
7. 7
   온도Heating
8. 8
   온도under reflux
9. 9
   온도the mixture is cooled
10. 10
    온도The whole is then heated
11. 11
    온도under reflux for 30 minutes
12. 12
    온도cooled
13. 13
    여과filtered
14. 14
    기타After recrystallisation from toluene, 28.7 g of 3,4-dimethoxybenzylthio-acetic acid
15. 15
    기타are obtained

실험 절차

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.

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