反应详情

15.2 g (0.2 mol) of thiourea in 100 ml of water are introduced into a 1 liter 3-necked flask. The mixture is heated to 50°-60° C. and 39.1 g (0.2 mol) of 2,4-dichlorobenzylchloride are introduced in a single operation. The mixture is heated under reflux and boiling is maintained for 15 minutes; the solution becomes limpid. The mixture is cooled and a solution of 32 g (0.8 mol) of NaOH in 50 ml of water is introduced dropwise at about 60° C. The mixture is again heated under reflux for 30 minutes, cooled and a solution of about 0.28 mol of sodium chloroacetate (obtained by neutralising 26.46 g of chloroacetic acid in 200 ml of water with 23.52 g of NaHCO3) is introduced, dropwise, at 60°-70° C. The whole is then heated under reflux for 30 minutes, cooled, filtered and acidified with 3 N HCl; the precipitate obtained is filtered off the redissolved cold in dilute sodium bicarbonate solution, and this solution is washed with methylene chloride, filtered and again acidified. 41.7 g (yield: 83 %) of product are thus collected. Instantaneous melting point: 72°-73° C.

1. temperatureThe mixture is heated to 50°-60° C.
2. temperatureThe mixture is heated
3. temperatureunder reflux
4. temperatureboiling is maintained for 15 minutes
5. temperatureThe mixture is cooled
6. temperatureThe mixture is again heated
7. temperatureunder reflux for 30 minutes
8. temperaturecooled
9. customat 60°-70° C
10. temperatureThe whole is then heated
11. temperatureunder reflux for 30 minutes
12. temperaturecooled
13. filtrationfiltered
14. customthe precipitate obtained
15. filtrationis filtered off the redissolved cold in dilute sodium bicarbonate solution
16. washthis solution is washed with methylene chloride
17. filtrationfiltered