Stereoselective synthesis of novel antiproliferative steroidal (E,E) dienamides through a cascade aldol/cyclization process

The stereoselective and metal-free protocol involving a cascade aldol/cyclization process for the synthesis of steroidal (E, E) dienamides from steroidal α, α-dicyanoalkene was reported. This protocol efficiently achieved the construction of CC bond and selective conversion of cyano group into carboxamide in one-pot procedure under mild condition. Further biological evaluation showed that some of these compounds had moderate to excellent cytotoxic activities against all the tested cancer cell lines and were more potent than well-known drug 5-fluorouracil. Particularly, compound 3c represented excellent inhibitory effect against MCF-7 (IC₅₀ = 0.76 μM), which was about 10-fold more potent than 5-fluorouracil.