反応 #55092
ord-3193c8a1af014ccb9c4786376fc8f99c
反応方程式
反応物
試薬
反応条件
後処理
- 1その他equipped with a magnetic stirrer and a condenser
- 2温度The temperature is raised to 95° C.
- 3温度to cool
- 4ろ過these are filtered off
- 5その他The precipitate thus obtained
- 6温度The mixture is heated to 70° C.
- 7温度The whole is then heated
- 8温度under reflux for half an hour
- 9温度after which it is cooled
- 10その他the precipitate obtained
- 11workup.DISSOLUTIONis redissolved in
- 12洗浄the solution is washed with methylene chloride
- 13ろ過filtered over charcoal
- 14その他to precipitate 3,4-methylenedioxybenzylthio-acetic acid, which
- 15ろ過is filtered off
- 16その他After recrystallisation
実験手順
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.