Imidazolone-annellated triphenedioxazine pigments

High Performance Pigments. Edited by Edwin B. Faulkner and Russell J. Schwartz Copyright 2009 WILEY-VCH Verlag GmbH Co. KGaA, Weinheim ISBN 978-3-527-31405-8 

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Imidazolone-annellated triphenedioxazine pigments, also called benzimidazo-lone-dioxazine pigments, are a relatively new class of violet pigments with very good fastness properties and extremely high color strengths. The stractural formula is shown in Figure 20.1. 

The combination of benzimidazolone moieties with the triphenedioxazine chro-mophore leads to imidazolone-annellated triphenedioxazine pigments, also called benzimidazolone-dioxazine pigments (4). In these pigments, the carbazole fragments of P.V. 23 are replaced by benzimidazolone moieties (Figure 20.6). 

Figure 20.6 Imidazolone-annellated triphenedioxazine pigments of commercial interest.

Pigment Blue 80 and other imidazolone-annellated triphenedioxazine pigments are synthesized in an analogous manner as P.V. 23 and its linear isomer. 

Figure 20.7 Syntheses of imidazolone-annellated triphenedioxazine pigments.

Chlorine-free imidazolone-annellated triphenedioxazine pigments (1, X = H) can be synthesized in a similar way as route A by starting from 2,5-dihydroxy-ben-zoquinone and using Mn02 in H2SO4 in the oxidation step [10]. 

Crystal Engineering on Imidazolone-Annellated Triphenedioxazine Pigments... 

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