تفاعل #1461964

معادلة التفاعل

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

المذيبات

acetone

acetic acid

ظروف التفاعل

المعالجة

1. 1
   workup.ADDITION50 ml) is added to the reaction mixture
2. 2
   أخرىThe acetone is evaporated
3. 3
   استخلاصthe aqueous layer extracted with dichloromethane (3×50 ml)
4. 4
   تجفيفThe organic layer is dried (MgSO4)
5. 5
   ترشيحfiltered
6. 6
   أخرىevaporated
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
   غسيلthe dichloromethane is washed with citric acid (5% soln, 3×100 ml), saturated sodium bicarbonate (50 ml), and water (50 ml)
10. 10
    تجفيفThe organic layer is dried (MgSO4)
11. 11
    ترشيحfiltered
12. 12
    أخرىevaporated
13. 13
    أخرىto give
14. 14
    أخرىbe separated by silica gel column chromatography

الإجراء التجريبي

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.

المصدر