Cardenamides from Cardenolides: Cardiac and Anticancer Activities

Two ways are shown to transform cardioactive cardenolides into cardenamides [17β-(5-oxo-2,5-dihydropyrrol-3-yl)-5β,14β-androstane derivatives], and their derivatives by replacement of their ring oxygen by N-R. Cardioactivity is strongly decreased by this transformation. The comparatively easily accessible 21-oxocardenamides [17β-(2-maleimidyl)-steroids] are strongly thiol reactive and show remarkable anticancer activity.