On the slide I've from my teacher, quinones are defined as "aromatics compound". I've search on various books and on the internet and I've haven't found a proof of it.
I've ipotized that they could have a resonance structur with six pi electrons on the six-term cicle and one unpaired electron on the oxygens... it's a bit strange... however, nature uses his one-radical-form to do his electron-carrying, maybe it's noto SO strange, and this biradicalc structur could be bit significant for the real structure of the molecule?
I've not found non-aromatics addiction addiction on quinone six-terms cicle...