A set of disubstituted tetracyclic lactones has been synthesized and tested for potential antitumor activity. Several of them possess a noticeable cytotoxicity against L1210 and HT- 29 colon cells in vitro. Relationships between chain nature and biological properties were sought. Lactones with a pentyl or hexyl substituent at C-11 are the most active ones. The introduction of a functional group at the side chain of C-11 modified the potency; ...
