The leucos 11a-d are claimed to give blue gray images in electrolytic recording instead of the purple color of Methylene Violet from which they are derived.7
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As in the case of the leucos Azure A and B, the exocyclic acyl group is not eliminated on oxidation, resulting in a Methylene Blue-type cationic
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dye. The color obtained is rather muddy but this can be seen as desirable since a black leuco dye is much sought after.
Compound 12 can be described as a true leuco Methylene Violet since a purple image is obtained on oxidation with a metal nitrate.8a