The major crystalline products from permanganate oxidation of N-aryl-2-naphthylamines are 1,1′-coupling dimers. Structures were determined by instrumental methods and by degradation to known 7-aryldibenzo[c,g]-carbazoles. Also formed are significant quantities of carbon-nitrogen coupling products, believed to be the o-semidines. 7-Aryldibenzo[c,g]carbazoles are formed in minor amounts. No evidence was found for stable symmetrical tetraarylhydrazines.
Journal of Organic Chemistry33, no. 12 (1968): 4329–4332.