SYNTHESIS OF 7-OXO- AND 7-HYDROXY- DERIVATIVES OF STIGMASTEROL

摘要

Stigmasterol (la) is one of the main steroids of plants. Together with /3-sitosterol and campesterol, this substance ensures the functioning of plant cell membranes. Moreover, the biosynthesis of various biologically active steroids necessary for the normal vital activity of plants starts from phytosterols, including stigmasterol. Compounds of this type include, for example, the hydroxysteroids (3a-4a) detected in plants [1, 2], the structures of which are characterized by the same carbon skeleton as in the stigmasterol molecule. It has been established by numerous investigations [4-9] that phytosterol derivatives with oxygen-containing functions at C-7, including steroids (2a-4a), possess a pronounced antitumoral activity. This circumstance has induced us to undertake the synthesis of these substances from the commercially available stigmasterol, which is used as a raw material in drug manufacture. In the present paper we give the results of this investigation, which is a continuation of syntheses of 6-oxophytosteroids from/3-sitosterol [10] and stigmasterol [11] that we have performed previously.