Treatment of compounds bearing one or two 1-dimethylamino-1, 4-dihydropyridine moieties with the urea-hydrogen peroxide complex (UHP) led to their efficient aromatization. Double N-oxidation of 1, 8-diazaanthraquinones thus obtained is the first example of a double N- oxidation of a diaza heterocycle by UHP in trifluoroacetic acid. Treatment of the crude double N-oxides with tosyl chloride in acetonitrile–water afforded 1, 8-diazaanthracene-2, ...
[Booth, Paul M.; Fox, Christina, M. J.; Ley, Steve V. Journal of the Chemical Society, Perkin Transactions 1: Organic and Bio-Organic Chemistry (1972-1999), 1987 , p. 121 - 130]