Polyazo compounds containing benzhydrol as a component

Abstract

Azo dyestuffs of the formula: ##SPC1## In which n is zero or 1, R represents a hydrogen atom or an alkyl or aryl group, A.sub.1, A.sub.2 and A.sub.3 each represent the residue of a diazotisable aromatic primary amine, which may be the same or different with at least one of these residues containing at least one sulphonic or carboxylic acid group, and the nucleus B is unsubstituted or substituted by one or two nitro, hydroxy or water-solubilising groups, metalliferous complexes of such dyestuffs and salts of the dyestuffs and of their metalliferous complexes. The dyestuffs of the above formula where n is zero may be prepared by a process which comprises coupling the diazo derivative of a diazotisable aromatic primary amine or the diazo derivatives of two different amines A.sub.1 NH.sub.2 and A.sub.2 NH.sub.2 with a coupling compound of the formula: ##SPC2## In which B and R have the same meaning as in claim 1, at the rate of two molecules of amine to each molecule of coupling compound. The dyestuffs of the above formula where n is 1 may be prepared by a process which comprises coupling a coupling compound of the formula: ##SPC3## In which B and R have the same meanings as in claim 1 with the diazo derivative of a diazotisable aromatic primary amine A.sub.1 --NH.sub.2, having a coupling position, at the rate of one molecule of amine to each molecule of coupling compound, then the monoazo dye thus obtained is coupled with the diazo derivative of a diazotisable aromatic primary amine or with the diazo derivatives of two different amines A.sub.2 --NH.sub.2 and A.sub.3 --NH.sub.2. The dyestuffs are particularly suitable for dyeing or finishing leathers.