反应详情

温度

60 °C

A solution of 18.24 g (0.24 mol) of thiourea in 104 ml of 48% strength hydrobromic acid and 20 ml of water is introduced into a 1 liter three-necked flask equipped with a magnetic stirrer and a condenser. The mixture is heated at 60° C. and 27.6 g (0.2 mol) of p-methoxybenzyl alcohol are introduced. The temperature is raised to 95° C. and the mixture is allowed to cool. Crystals of the thiouronium salt appear; these are filtered off and dried. The precipitate obtained above is introduced into a 500 ml three-necked flask with 60 ml of NaOH. The mixture is heated to 70° C. and a solution of 15.6 g (0.164 mol) of chloroacetic acid dissolved in 30 ml of water is added dropwise. Thereafter the whole is heated under reflux for half an hour and then cooled. The mixture is acidified with 3 N HCl, the oil obtained is taken up in methylene chloride, and the mixture is washed with a dilute sodium bicarbonate solution, filtered over charcoal, and acidified once more with 3 N HCl in order to precipitate p-methoxybenzylthio-acetic acid. 25.7 g (yield 60%) of the said acid are collected (melting point=60° C.).

1. customequipped with a magnetic stirrer and a condenser
2. temperatureThe temperature is raised to 95° C.
3. temperatureto cool
4. filtrationthese are filtered off
5. customdried
6. customThe precipitate obtained
7. temperatureThe mixture is heated to 70° C.
8. additionis added dropwise
9. temperatureThereafter the whole is heated
10. temperatureunder reflux for half an hour
11. temperaturecooled
12. customthe oil obtained
13. washthe mixture is washed with a dilute sodium bicarbonate solution
14. filtrationfiltered over charcoal
15. customto precipitate p-methoxybenzylthio-acetic acid