Quinonoid Compounds Quinone from aniline

Quinone is produced in small yield by direct oxidation of benzene itself with silver peroxide, but better by the action of oxidising agents on a large number of its p-disubstitution products. Thus, in addition to quinol, p-aminophenol (experiment, p. 176), p-anisidine, p-toluidine, and sulphanilic acid as well as p-phenylenediamine and many of its derivatives yield quinone in this way. 

More easily than benzene, naphthalene can be oxidised directly to (a)-quinone this is the preparative method with anthracene and phenan-threne. 

Although quinone is a derivative of dihydrobenzene and therefore not genuinely aromatic , its formation from a suitable precursor is favoured whenever an oxidising agent gives out energy. 

The reactions of quinone consist essentially of various types of addition to the double bonds present in the molecule. This addition takes place  

To this scheme most of the reactions of quinone conform, and all those which are of most importance, e.g. the addition of HC1, HCN, amines, thiophenol, thiosulphuric acid, acid chlorides, and add anhydrides. 

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