Hoechst Aktiengesellschaft

Cassella Aktiengesellschaft

Norbert Armbrecht

Joachim Ribka

Wolfgang Bauer

Karl Sommer

Water soluble trisazo dyestuffs of the formula ##STR1## in which A is 1-amino-8-naphthol-3,6-disulfonic acid or 1-amino-8-naphthol-4,6-disulfonic acid, or a mixture of these two compounds, and B is 1-(3'- or 4'-aminophenyl)-3-methyl-5-pyrazolone, a process for their manufacture by diazotizing component A and coupling it with 3,3'-dihydroxy-diphenylamine to give a monoazo dyestuff, reacting this dyestuff with diazotized component B to give a disazo dyestuff, and converting this dyestuff to the trisazo dyestuff by uniting it with diazotized 4-nitro-4'-amino-diphenylamine-2-sulfonic acid, or by operating as described while, however, changing the sequence of reaction of component B and 4-nitro-4'-amino-diphenylamine-2-sulfonic acid, and use of these dyestuffs for the dyeing of leather and fur.

Water-soluble trisazo dyestuffs on the basis of a combination of

Leathers can be advantageously dyed with water-soluble polyazo dyestuffs having, in the form of the free acid, the formula ##STR1## wherein A is a member of the benzene, naphthalene or heterocyclic series;

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Sulzbach, Germany

Norbert Armbrecht