Imidazole dyes formed by reaction of imidazoles with diazonium salts

Abstract

Disclosed is an imidazole azo dye of formula (I), which is useful for image formation and as a filter dye, which has a sharp absorption wave and which is fast to light, heat, air, moisture and chemicals. Also disclosed is a thermal transfer dye-donating material containing imidazole azo dye(s) of formula (I) preferably along with aminopyrazole azo dye(s) of formula (II). The material gives a high-density image with good color reproduction, and the image formed has improved storage stability. ##STR1## In (I), B and C independently represent a hydrogen atom or a substituent capable of being substituted in the imidazole ring; A represents an aryl or heterocyclic group; provided that when B is a hydrogen atom, C is not a hydrogen atom nor an alkyl group having from 1 to 3 carbon atoms; provided that when C is a hydrogen atom, B is not a substituted nor unsubstituted alkyl group; provided that C is not a mercapto group or an alkylthio group; and provided that B is not a carboxyl group. In (II), D represents a hydrogen atom, or an alkyl, aryl, or heterocyclic group, E represents a substituent capable of being substituted in the pyrazole ring, F represents an aryl or heteroaromatic group, and G and I independently represent a hydrogen atom, or an alkyl, aryl, or heterocyclic group.