反応 #55323

反応方程式

Cholestan-3-one

benzeneseleninic anhydride

→

cholesta-1,4-dien-3-one

収率 64.0%

溶媒

chlorobenzene

反応条件

後処理

1. 1
   温度the solution heated
2. 2
   温度to reflux
3. 3
   その他reaction
4. 4
   温度to cool
5. 5
   ろ過before filtering down a short silica column
6. 6
   洗浄washing with petrol containing 10% methylene chloride
7. 7
   洗浄by washing with methanol
8. 8
   その他On evaporation an oil (107.1 mg)
9. 9
   その他was obtained which
10. 10
    その他crystallised
11. 11
    温度on cooling in cardice

実験手順

Cholestan-3-one (100 mg) was dissolved in chlorobenzene (5 ml), benzeneseleninic anhydride (188 mg, 2 equiv.) added and the solution heated to reflux with stirring under nitrogen in the dark. After 3 hours tlc showed almost complete reaction. The mixture was allowed to cool before filtering down a short silica column, washing with petrol containing 10% methylene chloride followed by releasing the crude product by washing with methanol. On evaporation an oil (107.1 mg) was obtained which crystallised on cooling in cardice. mp. 50°-57° C. Plc of the resulting impure product yielded 63.3 mg (63%) of cholesta-1,4-dien-3-one mp. 110°-112° C. (literature melting point 112° C.). λmax. 242 nm (ε 14500) (literature U.V. absorption 242 nm (ε 15000)). I.R. spectrum identical to previously prepared pure samples. The results of several runs are tabulated below:

出典