Electroreduction of Derivatives of N,N'-Dioxides of Phenazine and Quinoxaline in Nonaqueous Media and in the Presence of Proton Donors of Medium Strength

Abstract

The electroreduction (ER) of benzo[a]phenazine-7,12-dioxide (1) and 2-ethoxycarbonyl-3-methyl-quinoxaline-1,4-dioxide (2) in DMF on a glassy carbon electrode is studied by the methods of cyclic voltammetry, chronoamperometry, and electrolysis at controlled potential. In aprotic medium, these compounds are reduced to form relatively stable complexes as observed in both cyclic voltammetry curves and UV spectra. The deoxygenation of the derivatives of phenazine and quinoxaline N,N′-dioxides proceeds as a result of decomposition of the radical formed either at the ER of complexes of these compounds with СН3СООН or as a result of protonation of radical anions. For compound 2, the competition between the reactions of decomposition and ER of this radical is observed.