Partialsynthesen von Cardenoliden und Cardenolid‐Analogen. VII. Synthese A/B‐cis‐ und C/D‐cis‐verknüpfter Steroidmono‐ und ‐bis(α‐methylen‐γ‐butyrolactone)

Abstract

Partial Syntheses of Cardenolides and Cardenolide Analogues. VII. Synthesis of A/B‐cis‐ and C/D‐cis‐linked Steroidal Mono‐ and Bis (α‐methylene‐γ‐butyrolactones)The synthesis of A/B‐cis‐ and C/D‐cis‐linked steroidal mono‐ and bis(α‐methylene‐γ‐butyrolactones) 10–13, 18 and 24 by Reformatsky‐type reaction of 3β‐acetoxy‐14‐hydroxy‐5β, 14β‐androstan‐17‐one( 6), 14‐hydroxy‐5β, 14β‐androstane‐3,17‐dione (8), 3β‐acetoxy‐14‐hydroxy‐5β,14β‐pregnan‐20‐one (17) and 14‐hydroxy‐5β,14β‐pregnane‐3,20‐dione (23), respectively, with ethyl α‐(bromomethyl)acrylate is described. All steroidal lactones exhibit strong inhibitory activity on the proliferation of Ehrlich ascites carcinoma cells in suspension culture. For inhibitory activity the lactone moiety at C‐17 of the steroid molecule is more important than the lactone moiety at C–3 and C–20, respectively.