反応 #1461964

反応方程式

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

溶媒

acetone

acetic acid

反応条件

後処理

1. 1
   workup.ADDITION50 ml) is added to the reaction mixture
2. 2
   その他The acetone is evaporated
3. 3
   抽出the aqueous layer extracted with dichloromethane (3×50 ml)
4. 4
   乾燥The organic layer is dried (MgSO4)
5. 5
   ろ過filtered
6. 6
   その他evaporated
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
   洗浄the dichloromethane is washed with citric acid (5% soln, 3×100 ml), saturated sodium bicarbonate (50 ml), and water (50 ml)
10. 10
    乾燥The organic layer is dried (MgSO4)
11. 11
    ろ過filtered
12. 12
    その他evaporated
13. 13
    その他to give
14. 14
    その他be separated by silica gel column chromatography

実験手順

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.

出典