Reaktion #1808485

Reaktionsgleichung

7-dehydrocholesterol

benzoyl chloride

→

3β-Benzoyloxy-5α-Cholestane

Lösungsmittel

pyridine

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.ADDITIONwas added
2. 2
   workup.ADDITIONAfter the addition
3. 3
   Temperaturthe reaction mixture was heated
4. 4
   Temperaturat reflux for 5 min
5. 5
   workup.ADDITIONThe reaction mixture was poured
6. 6
   workup.WAITto rest for 1 h
7. 7
   Filtrationa filter
8. 8
   Waschenwashed successively with water (350 mL), 5% sodium bicarbonate (200 mL), water (350 mL) and finally acetone (5×25 mL)
9. 9
   Sonstigedried
10. 10
    Sonstigesubsequently recrystallized
11. 11
    workup.DISSOLUTIONThe crude material was dissolved in hot chloroform (100 mL) and to this solution
12. 12
    workup.ADDITIONwas added acetone (250 mL)
13. 13
    workup.WAITThe flask was left at ambient temperature
14. 14
    Sonstigeat -20° C.
15. 15
    Sonstigeovernight
16. 16
    FiltrationThe crystalline material was collected by filtration
17. 17
    Waschenwashed with a small amount of acetone
18. 18
    TrocknenTotal yield compound 2 after drying

Vorschrift

To a solution of 7-dehydrocholesterol (1, 50.0 g, 0.13 mol; Aldrich Chemical Co.) dissolved in dry pyridine (120 mL) was added, with stirring, benzoyl chloride (28 mL, 34.1 g, 0.24 mol). After the addition, the reaction mixture was heated at reflux for 5 min and was then left at ambient temperature for 20 min. The reaction mixture was poured with stirring into ice water (1.5 L). The precipitate was allowed to rest for 1 h and was then taken up on a filter and washed successively with water (350 mL), 5% sodium bicarbonate (200 mL), water (350 mL) and finally acetone (5×25 mL). The crude material was air dried and subsequently recrystallized. The crude material was dissolved in hot chloroform (100 mL) and to this solution was added acetone (250 mL). The flask was left at ambient temperature and then at -20° C. overnight. The crystalline material was collected by filtration, and then washed with a small amount of acetone. Total yield compound 2 after drying, 58.3 g (92%). Melting point and spectral data agree with previous reported values (Wilson et al., J. Org. Chem. 53:1713 (1988)).

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