Phenoxazinium salts

The blue dye (47), formed from the autoxidation of 4-/V,TV-di methyl-amino-2-hydroxyaniline, is the oxygen analogue of methylene blue. The autoxidation of 1,2,4-trihydroxybenzene, carried out in the presence of ammonia, gives the hydroxyphenoxazinone dye (48) via a 2,4-dihydroxyani-line intermediate (Scheme 17). Many types of phenoxazines, phenazines, and phenoxazinium salts can be obtained by autoxidation of polyhydroxyben-zenes and their amino derivatives. Some autoxidative dyes may give poly-... 

Gorton, L., Torstensson, A., Jaegfeldt, H., Johansson, G., Electrocatalytic Oxidation of Reduced Nicotinamide Coenzymes by Graphite Electrodes Modified with an Adsorbed Phenoxazinium Salt, Meldola Blue , / Electroanal. Chem. 161 (1984) 103-120. 

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