反应详情

A mixture of 11.78 g of 2,4-dichlorothiophenol and 12.0 g of potassium hydroxide in 50 ml of acetone was stirred and heated to reflux. 11.77 g of ethyl 2-bromopropionate were added gradually and the mixture was heated under reflux for 22 hours. After cooling to room temperature, the mixture was filtered and the filtrate was evaporated to dryness. The residue was taken up in 400 ml of diethyl ether and the solution was washed with 400 ml of water and 400 ml of 10% sodium carbonate solution, dried over anhydrous sodium sulfate and evaporated to dryness. A solution of the residue in a mixture of 30 ml of ethanol and 17 ml of 10% potassium hydroxide solution was heated under reflux for 21 hours. The solution was evaporated to dryness and the residue was dissolved in 50 ml of water. The resulting solution was washed twice with 50 ml of diethyl ether each time and then acidified with concentrated hydrochloric acid and extracted twice with 150 ml of ethyl acetate each time. The combined organic extracts were washed twice with 200 ml of water each time, dried over anhydrous sodium sulfate and evaporated to dryness. The residue was recrystallized from diethyl ether to give 4.08 g of 2(RS)-(2,4-dichlorophenyl-thio)propionic acid in the form of a yellow solid of melting point 95°-98° C.

1. temperatureheated to reflux
2. temperaturethe mixture was heated
3. temperatureunder reflux for 22 hours
4. filtrationthe mixture was filtered
5. customthe filtrate was evaporated to dryness
6. washthe solution was washed with 400 ml of water and 400 ml of 10% sodium carbonate solution
7. dry with materialdried over anhydrous sodium sulfate
8. customevaporated to dryness
9. additionA solution of the residue in a mixture of 30 ml of ethanol and 17 ml of 10% potassium hydroxide solution
10. temperaturewas heated
11. temperatureunder reflux for 21 hours
12. customThe solution was evaporated to dryness
13. dissolutionthe residue was dissolved in 50 ml of water
14. washThe resulting solution was washed twice with 50 ml of diethyl ether each time
15. extractionextracted twice with 150 ml of ethyl acetate each time
16. washThe combined organic extracts were washed twice with 200 ml of water each time
17. dry with materialdried over anhydrous sodium sulfate
18. customevaporated to dryness
19. customThe residue was recrystallized from diethyl ether