Reaktion #1461964

Reaktionsgleichung

sodium sulphite

N-Bromoacetamide

5,14-diene

3β,12β-Dihydroxy-20,20-ethylenedioxypregn-5,14-diene

water

→

3β,12β-Dihydroxy-5,6-epoxy-20,20-ethylenedioxypregn-14-ene

Lösungsmittel

acetone

acetic acid

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.ADDITION50 ml) is added to the reaction mixture
2. 2
   SonstigeThe acetone is evaporated
3. 3
   Extraktionthe aqueous layer extracted with dichloromethane (3×50 ml)
4. 4
   TrocknenThe organic layer is dried (MgSO4)
5. 5
   Filtrationfiltered
6. 6
   Sonstigeevaporated
7. 7
   workup.ADDITIONPyridine (1 ml) is added to the product
8. 8
   workup.ADDITIONDichloromethane (100 ml) is then added to the reaction mixture
9. 9
   Waschenthe dichloromethane is washed with citric acid (5% soln, 3×100 ml), saturated sodium bicarbonate (50 ml), and water (50 ml)
10. 10
    TrocknenThe organic layer is dried (MgSO4)
11. 11
    Filtrationfiltered
12. 12
    Sonstigeevaporated
13. 13
    Sonstigeto give
14. 14
    Sonstigebe separated by silica gel column chromatography

Vorschrift

N-Bromoacetamide (211 mg, 1.5 mmol) is added to a stirred solution of the 5,14-diene (23) (500 mg, 1.34 mmol) in acetone (100 ml), acetic acid (2.5 ml), and water (5 ml) at 0° C. After 15 min sodium sulphite (5% soln, 50 ml) is added to the reaction mixture. The acetone is evaporated, and the aqueous layer extracted with dichloromethane (3×50 ml). The organic layer is dried (MgSO4), filtered and evaporated. Pyridine (1 ml) is added to the product, and stirred for 0.5 h. Dichloromethane (100 ml) is then added to the reaction mixture, and the dichloromethane is washed with citric acid (5% soln, 3×100 ml), saturated sodium bicarbonate (50 ml), and water (50 ml). The organic layer is dried (MgSO4), filtered and evaporated to give the mixture of 14,15- and 5,6-epoxides (360 mg, 69%) as a white foam. The mixture of epoxides could not be separated by silica gel column chromatography.

Quelle