Concise synthesis and voltammetric studies of dielsiquinone, a cytotoxic azaanthraquinone.

We have developed a concise synthesis of dielsiquinone 1, a potent cytotoxic agent related to anthraquinones. Electrochemical studies have shown that dielsiquinone is reduced to a semiquinone radical that does not react with O2 to generate toxic reactive oxygen species. These results strongly suggest that 1 should be less cardiotoxic than anthracyclines used in clinic and may therefore provide the basis for the development of safer anticancer drugs.