Persulphate oxidations. Part XI. Oxidative dimerisation of aminonaphthoquinones

Abstract

Persulphate oxidation of 2-amino-, 2-methylamino- and 2-ethylamino-1,4-naphthoquinone generated vinylogous π-amidyls which dimerised on carbon to form 3,3′-diamino-2,2′-binaphthoquinonyls; these may subsequently cyclise to dibenzocarbazolediquinones. Similar treatment of 2-dimethylamino-1,4-naphthoquinone gave a dinaphthofurandiquinone. Oxidation of 2-alkylamino-3-phenyl-1,4-naphthoquinones afforded benzocarbazolequinones; the 2-anilino- and 2-o-toluidino-analogues formed, in addition, NN′-dinaphthoquinonylbenzidines.