Electrochemical behavior of ellipticine derivatives: Part III. Reduction of 2-methyl-ellipticinium cations and their conjugated bases

In neutral DMF, ellipticinium cations 9 R—E⁺H—2 CH₃ undergo a reversible 1 e addition (standard potential ca. ?1.35 V) to yield a neutral radical which rapidly dimerizes (dimerization rate constant ca. 10⁷ mol^?1 1 s^?1). In basic DMF or in the presence of superoxide anion, the corresponding conjugated bases undergo a reversible 1 e addition accompanied by a fast and reversible proton addition (standard potential at pH_DMF 0 ca. ?0.52 V) to yield the same neutral radical. R being H, OCH₃ or OH, there is no effect of the substituent at the C-9 position on the electrochemical process.