THE FORMATION OF RELATIVELY STABLE PROTONATED ANION-RADICALS IN THE CATHODIC HYDROGENATION OF QUINONEMETHIDES

Examination of the cathodic hydrogenation of two examples of quinoneme thides reveals an unusual pathway in which the anion radicals of the q uinonemethides fuchsone and its dimethyl analogue are protonated rever sibly at oxygen by substituted phenols in DMSO to give relatively stab le triarylmethyl radicals which are not reduced at the first reduction potential of the quinonemethides; this behaviour contrasts with that usually found, i.e. anion-radicals are usually formed at more cathodic potentials than reduction potentials of radicals derived from them by protonation.