3-hydroxypyridineazomethine dye

Abstract

A 3-hydroxypyridineazomethine dye represented by general formula (I) ##STR1## wherein R.sub.1 represents an aliphatic group, an aromatic group, or a heterocyclic group; R.sub.2 represents an aliphatic group, an aromatic group, a heterocyclic group, an alkoxy group, an aryloxy group, an alkenyloxy group, an amino group, an acyl group, an ester group, an amido group, a carbamoylamino group, a sulfamoylamino group, a sulfamido group, an imido group, a ureido group, an aliphatic or an aromatic sulfonyl group, an aliphatic or an aromatic thio group, a hydroxyl group, a cyano group, a carboxy group, or a halogen atom; R.sub.3 represents an aryl group; Y represents a bivalent linking group containing at least one of amide bond and ester bond; n represents 0, 1 or 2; where n is 2, the two R.sub.2 groups may be the same group or atom or may be mutually different groups or atoms, or the two R.sub.2 groups may form a ring; where n is 1 or more, R.sub.1 and R.sub.2 may form a ring; and at least one of R.sub.1 and R.sub.2 may contain at least one residual group formed by removing R.sub.1 or R.sub.2 from general formula (I), as a substituent; and a method of preparing the dye by an oxidizing coupling reaction of 3-hydroxypyridine and a p-phenylenediamine or a p-aminophenol, or a dehydration condensation reaction of a 3-hydroxypyridine and a nitroso compound.