2,4-Dichlorobenzyl chloride → 2,4-Dichlorobenzylthio-acetic acid

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Reaction Steps

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.

Provenance & Evidence