Notes
Conversion of Spirostane and Solanidane into Pregnane (1)
Introduction of Oxygen Function into C-23
Introduction of Oxygen Function into C-23
2012 年 60 巻 1 号 p. 150-153
詳細
2012 年 60 巻 1 号 p. 150-153
A spirosolane derivative possessing a hydroxyl group at C-23, esculeogenin A, a sapogenol of tomato saponin, was found to be easily converted into the corresponding pregnane derivative by refluxing with aqueous pyridine. Therefore, introduction of a hydroxyl group into the C-23 of diosgenin (as representative of spirostane derivatives) and solasodine (as representative of spirosolane derivatives) was attempted by the reaction of NaNO2–BF3 · Et2O. In diosgenin, the objective compound was obtained by the reaction in AcOH. However, in solasodine, we obtained a 23-nitroso derivative by the reaction in AcOH and 23,24-bisnorcholanic acid 22-16 lactone, or vespertilin, in AcOH and CHCl3.
