Reaktion #93796

Reaktionsgleichung

ethanethiol

propylene oxide

bromine

sodium hydrogencarbonate

diketene

→

4-bromo-3-oxothiobutyric acid-S-ethyl ester

Ausbeute 58.2%

Lösungsmittel

methylene chloride

water

methylene chloride

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturwhile maintaining the temperature at -40° to -35° C. over a period of 1 hour
2. 2
   Sonstigethe resulting mixture was subjected to reaction at -30° to -20° C. for 30 minutes
3. 3
   Temperaturthe resulting solution was cooled to -40° C
4. 4
   workup.ADDITIONInto this solution was introduced the above-mentioned reaction mixture
5. 5
   TemperaturThen, the temperature of the reaction mixture was raised up to room temperature over a period of 1 hour
6. 6
   Sonstigethe mixture was further subjected to reaction at the same temperature for 1 hour
7. 7
   SonstigeThe organic layer was separated
8. 8
   Waschenwashed with 30 ml of saturated aqueous sodium chloride solution
9. 9
   Trocknendried over anhydrous magnesium sulfate
10. 10
    SonstigeThe solvent was removed by distillation under reduced pressure
11. 11
    Sonstigethe residue obtained
12. 12
    workup.DISTILLATIONwas distilled under reduced pressure

Vorschrift

In 40 ml of anhydrous methylene chloride was dissolved 8.4 g of diketene, and the resulting solution was cooled to -40° C. Then, 14.4 g of bromine was added dropwise to the solution while maintaining the temperature at -40° to -35° C. over a period of 1 hour, and the resulting mixture was subjected to reaction at -30° to -20° C. for 30 minutes. On the other hand, 7.48 g of ethanethiol and 5.84 g of propylene oxide were dissolved in 60 ml of anhydrous methylene chloride, and the resulting solution was cooled to -40° C. Into this solution was introduced the above-mentioned reaction mixture. Then, the temperature of the reaction mixture was raised up to room temperature over a period of 1 hour, and the mixture was further subjected to reaction at the same temperature for 1 hour. The reaction mixture was introduced into 100 ml of water at 5° C., and the pH was adjusted to 6.0 with sodium hydrogencarbonate. The organic layer was separated, washed with 30 ml of saturated aqueous sodium chloride solution and then dried over anhydrous magnesium sulfate. The solvent was removed by distillation under reduced pressure and the residue obtained was distilled under reduced pressure to obtain 11.8 g (yield, 58.0%) of 4-bromo-3-oxothiobutyric acid-S-ethyl ester having a boiling point of 110°-120° C./4 mmHg.

Quelle