| abstract |
Tryptanthrine derivative of the formula <IMAGE> where the rings A and B may be benzofused and/or substituted and X is a radical which is derived from a CH-acidic heterocyclic structure which may have a further tryptanthrine radical or from a hydrazinoanthraquinone or, if one or both of the rings A and B are benzofused and/or substituted by phthaloyl, is furthermore oxygen, are used as colorants. |