반응 #55092
ord-3193c8a1af014ccb9c4786376fc8f99c
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시약
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후처리
- 1기타equipped with a magnetic stirrer and a condenser
- 2온도The temperature is raised to 95° C.
- 3온도to cool
- 4여과these are filtered off
- 5기타The precipitate thus obtained
- 6온도The mixture is heated to 70° C.
- 7온도The whole is then heated
- 8온도under reflux for half an hour
- 9온도after which it is cooled
- 10기타the precipitate obtained
- 11workup.DISSOLUTIONis redissolved in
- 12세척the solution is washed with methylene chloride
- 13여과filtered over charcoal
- 14기타to precipitate 3,4-methylenedioxybenzylthio-acetic acid, which
- 15여과is filtered off
- 16기타After recrystallisation
실험 절차
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 one liter three-necked flask equipped with a magnetic stirrer and a condenser. The mixture is heated to 60° C. and 30.4 g (0.2 mol) of piperonyl alcohol are introduced. The temperature is raised to 95° C. and the mixture is allowed to cool. Crystals of thiouronium salt appear; these are filtered off and suction-drained. The precipitate thus obtained is introduced into a 500 ml three-necked flask together with 60 ml of sodium hydroxide solution. The mixture is heated to 70° C. and 15.6 g (0.164 mol) of chloroacetic acid in 30 ml of water are added dropwise. The whole is then heated under reflux for half an hour, after which it is cooled. The mixture is acidified with 3 N HCl, the precipitate obtained is redissolved in a dilute (sodium) bicarbonate solution, and the solution is washed with methylene chloride, filtered over charcoal and again acidified with 3 N HCl so as to precipitate 3,4-methylenedioxybenzylthio-acetic acid, which is filtered off. After recrystallisation from a 1:1 (volume/volume) mixture of diisopropyl ether and petroleum ether, 18.2 g (40% yield) of the said acid (instantaneous melting point=87° C.) are collected.