3,5-Bis(benzylidene)-1-[3-(2-hydroxyethylthio)propanoyl]piperidin-4-ones: a novel cluster of potent tumor-selective cytotoxins.

Novel 3,5-bis(benzylidene)-1-[3-(2-hydroxyethylthio)propanoyl]piperidin-4-ones (3a-e) display potent cytotoxicity and a preferential lethality toward various neoplasms compared to some normal cells. The corresponding sulfonic acid analogues 5a-e and an isostere 4 demonstrated substantially lower activity. The leads 3d and 3e possess very high activity against colon cancer and leukemia cell lines, caused DNA fragmentation, and activated caspase-3 in HL-60 cells. The enones 3b-e were well tolerated in a short-term toxicity screen in mice.