Neuartige Umwandlungen bei den Steroiden

Summary The problem of an efficient partial synthesis of the important corticosteroidal hormone, aldosterone, involves the ability to obtain steroids with functional groups at C-18. Thus, naturally occuring steroid alkaloids, holarrhimine and conessine, were degraded to nitrogen-free 18-hydroxysteroids.In order to find other more efficient methods of synthesis, attempts were made to effect direct functionalization of the unactivated angular methyl group 18 in steroids. This was achieved by known and by novel intramolecular substitution procedures.In the course of these investigations, conessin-type compounds, novel pentacarbocyclic steroids with four-and five-membered E ring as well as novel 18,20-oxido steroids were synthesized from pregnane derivatives. The lead tetraacetate oxidation of 20-hydroxypregnanes, leading to ether formation between C-18 and C-20, ultimately provided the key step for the first partial synthesis ofnat.-aldosterone. The latter work was carried out in close collaboration with the research group of the Pharmaceutical Department of CIBA Ltd., Basle.

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Erweiterte Fassung eines am 6. 5. 59 in der Zürcher Chemischen Gesellschaft sowie am 11. 6. 59 in der CIBA AG., Basel, vom Seniorautor gehaltenen Vortrages.