A novel hexa-cyclic compound, a derivative of camptothecin, of the general formula: ##STR1## The compound is prepared from an aminoketone compound and a pyranoindolizine compound through Friedlaender reaction. It has an excellent antitumor activity and a high degree of safety, and can be applied as an antitumor medicine for curing tumors of various kinds.
and F-modified hexacyclic analogues of camptothecin were synthesized by Friedlander condensation of appropriately substituted bicyclic amino ketones with tricyclic ketone and were evaluated for cytotoxicity and topoisomerase I inhibitory activity. Seventeen of the compounds showed cytotoxic effects comparable or superior to those of 7-ethyl-10-hydroxycamptothecin (SN-38) against mouse leukemia P388 and