Rebeccamycin antitumor activity

Rebeccamycin (44) was shown to have antitumor activity against P388 leukemia, L1210 leukemia and B16 melanoma implanted in mice [27]. It is believed to impart this effect through the single strand cleavage of DNA. Water-soluble analogues... 

This chemistry has provided one of the most direct routes to the indolo[2,3-a]carbazole alkaloid ring system (Scheme 11), a common functionality of several biologically active molecules such as the potent antitumor agent rebeccamycin and arcyriaflavin A. The indolo[2,3-fl]carbazole derivative has been obtained in satisfactory yield through the reaction of l,4-di((9-trifluoroacetamidophenyl)-l,3-butadiyne with 3,4-dibromomaleimide in the presence of tetrakis(triphenylphosphine)palladium(0) and potassium carbonate. The proposed mechanism of this polyannulation process, which generates four new bonds in a single step, is outlined in Scheme 12. 

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