Реакция #354805

Уравнение реакции

2β-bromo-3α-hydroxy-17β-methoxycarbonyl-5α-androstan-11-one

dihydropyran

p-toluenesulphonic acid

lithium bromide

calcium carbonate

→

title compound

3α-Hydroxy-17β-methoxycarbonyl-5α-androst-1-en-11-one

Растворители

dimethylacetamide

benzene

Условия реакции

Обработка

1. 1
   Промывкаbefore being washed with aqueous 10% sodium bicarbonate and water
2. 2
   СушкаThe benzene solution was dried
3. 3
   Другоеevaporated
4. 4
   Другоеto give a gum which
5. 5
   Температураwas heated (100°) for 6 hr
6. 6
   ТемператураCooling
7. 7
   Фильтрацияdilution with chloroform and filtration
8. 8
   Другоеgave a solution which
9. 9
   Промывкаwas washed with water
10. 10
    Другоеdried
11. 11
    Фильтрацияfiltered
12. 12
    Другоеevaporated
13. 13
    workup.DISSOLUTIONThe residue was dissolved in methanol (200 ml.)
14. 14
    workup.ADDITIONcontaining aqueous 2N hydrochloric acid (1 ml.) After 4 hr
15. 15
    Другоеthe methanol was removed by evaporation and chloroform
16. 16
    workup.ADDITIONadded
17. 17
    ПромывкаThis solution, after being washed with aqueous 10% sodium bicarbonate and water
18. 18
    Другоеwas dried
19. 19
    Фильтрацияfiltered
20. 20
    Другоеevaporated to an oil
21. 21
    workup.ADDITIONThe addition of ether

Методика

A solution of 2β-bromo-3α-hydroxy-17β-methoxycarbonyl-5α-androstan-11-one. (3.48g.,), dihydropyran (8 ml.) and p-toluenesulphonic acid (60 mg.) in benzene (150 ml.) was stirred at room temperature for 15 minutes before being washed with aqueous 10% sodium bicarbonate and water. The benzene solution was dried and evaporated to give a gum which was dissolved in dimethylacetamide (120 ml.). After the addition of anhydrous lithium bromide (14.4g.) and calcium carbonate (11.2g.) the mixture was heated (100°) for 6 hr. Cooling, dilution with chloroform and filtration gave a solution which was washed with water, dried, filtered and evaporated. The residue was dissolved in methanol (200 ml.) containing aqueous 2N hydrochloric acid (1 ml.) After 4 hr. the methanol was removed by evaporation and chloroform added. This solution, after being washed with aqueous 10% sodium bicarbonate and water, was dried, filtered and evaporated to an oil. The addition of ether resulted in crystallisation of the title compound (1.125g.); m.p. 172°-175°; [α]D + 40°, (c 0.7).

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