反应详情

15.2 g (0.2 mol) of thiourea in 100 ml of water are introduced into a 1 liter three-necked flask. The mixture is heated at 50°-60° C. and 39.1 g (0.2 mol) of 2,4-dichlorobenzyl chloride are added all at once. The mixture is heated to reflux and boiling is maintained for 15 minutes; the solution becomes limpid. It is then cooled and a solution of 32 g (0.8 mol) of NaOH in 50 ml of water is added 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 added dropwise at 60°-70° C. Thereafter the whole is heated under reflux for 30 minutes, cooled, filtered and acidified with 3 N HCl; the precipitate obtained is filtered off and redissolved whilst cold in dilute bicarbonate solution, and this solution is washed with methylene chloride, filtered and acidified once more. 41.7 g (yield 83%) of the product are thus collected. Instantaneous melting point 72°-73° C.

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