AZO compounds and process for producing the same

An azo compound having the general formula [I]:

• wherein Y is —(CONH)n-X or an optionally esterified carboxyl group,
• Y′ is —(CONH)n-X′ or an optionally esterified carboxyl group,
• (wherein X and X′ are optionally substituted and/or branched saturated or unsaturated aliphatic hydrocarbon groups, optionally substituted aromatic groups, or optionally substituted heterocyclic groups having conjugated double bonds,
• n is an integer of 1 or 2,
• provided that when either Y or Y′ is a carboxylic group, said carboxylic group may optionally form an acceptable salt),
• R2 is a hydrogen atom, an optionally branched alkyl group having 1-6 carbon atoms, an acyl group having 1-6 carbon atoms or a phenyl alkyl group,
• Q is an optionally branched alkyl group having 1-6 carbon atoms, an optionally branched alkoxy group having 1-6 carbon atoms, a halogen atom, a sulfo group, a nitro group, a nitroso group, or an amino group,
• m is an integer of 0-3, provided that when m is 1, the Q may be combined with either of the two condensed rings, when m is 2 or 3, the Qs may be combined with either or both of the condensed rings, or may form a ring together with the two condensed rings, and
• Z is an optionally substituted monovalent aromatic group;
• provided that at least one of Y and Y′ represents a group wherein X or X′ is an optionally substituted and/or branched unsaturated or saturated aliphatic hydrocarbon group.