Reaktion #5215

Reaktionsgleichung

thioacetic acid

triphenylphosphine

4-hydroxy-2-pyrrolidinone

diethyl azodicarboxylate

→

4-acetylthio-2-pyrrolidinone

Lösungsmittel

tetrahydrofuran

tetrahydrofuran

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturafter which it was cooled to -20° C
2. 2
   Temperaturwhilst cooling at -12° C. to -20° C., to the previous solution
3. 3
   workup.STIRRINGThe mixture was then stirred at 0°-5° C. for 5 minutes
4. 4
   Temperaturafter which it was again cooled to -20° C
5. 5
   Temperaturwhilst cooling at -18° C. to -20° C
6. 6
   TemperaturThe mixture was then warmed to 0°-5° C.
7. 7
   workup.STIRRINGstirred at that temperature for 2 hours
8. 8
   EinengenAt the end of this time, the reaction mixture was concentrated by evaporation under reduced pressure
9. 9
   SonstigeThe residue was purified first by column chromatography through silica gel
10. 10
    Wascheneluted with a 10:1 by volume mixture of ethyl acetate and methanol
11. 11
    Waschenby column chromatography through silica gel, eluted with a 2:1 by volume mixture of acetonitrile and benzene

Vorschrift

20-(1) 15.6 g of triphenylphosphine were added to a suspension of 3 g of 4-hydroxy-2-pyrrolidinone in 200 ml of tetrahydrofuran, and then the mixture was stirred at room temperature for 5 minutes, after which it was cooled to -20° C. A solution of 9.3 ml of diethyl azodicarboxylate in 9 ml of tetrahydrofuran was added dropwise, whilst cooling at -12° C. to -20° C., to the previous solution. The mixture was then stirred at 0°-5° C. for 5 minutes, after which it was again cooled to -20° C. 4.2 ml of thioacetic acid were then added dropwise to the mixture, whilst cooling at -18° C. to -20° C. The mixture was then warmed to 0°-5° C. and stirred at that temperature for 2 hours. At the end of this time, the reaction mixture was concentrated by evaporation under reduced pressure. The residue was purified first by column chromatography through silica gel, eluted with a 10:1 by volume mixture of ethyl acetate and methanol, and then by column chromatography through silica gel, eluted with a 2:1 by volume mixture of acetonitrile and benzene, to give 2.45 g of 4-acetylthio-2-pyrrolidinone as colorless crystals.

Quelle