Tetrakisazo Dyestuffs

The subject matter of the present invention relates to tetrakisazo dyestuffs which in the acid form correspond to the formula ##STR2## wherein Z.sub.1, Z.sub.2 = an optionally substituted amino group

R = h or a non-ionogenic substituent, in particular halogen or alkyl,

n = an integer of 1 to 3,

The rings A and B possibly having further substituents, for example, alkoxy groups, such as methoxy groups, and the substituents R as well as Z.sub.1 and Z.sub.2 being the same or different.

Preferred substituents R are optionally substituted alkyl groups, in particular those with 1 - 4 C atoms and halogen, in particular chlorine as well as NO.sub.2. The preferred radicals Z.sub.1 and Z.sub.2 are amino groups as well as monoalkylamino groups with an alkyl group which may be substituted, for example, by hydroxyl, sulphonic acid or carboxylic acid groups, said preferred radicals being in particular those groups with 1 to 4 C atoms in the alkyl radical, in addition acylamino groups, in particular acetylamino groups or aminocarbonylamino groups.

Preferred dyestuffs are accordingly those which in the acid form correspond to the formula ##STR3## wherein R' = H, C.sub.1 - C.sub.4 alkyl, Cl, NO.sub.2,

n = an integer from 1 to 2

as well as those which in the form of the free acid correspond to the formula ##STR4## wherein R' = H, C.sub.1 - C.sub.4 alkyl, Cl, NO.sub.2,

n = an integer from 1 to 2

Y = an optionally substituted C.sub.1 - C.sub.4 alkyl, in particular by hydroxy, SO.sub.3 H or COOH; aminocarbonyl.

The new dyestuffs of the formula (I) are obtained by coupling a tetrazotised amine of the formula ##STR5## with 2 mol of 2-amino-8-hydroxynaphthalene-3,6-disulphonic acid to produce diaminodisazo dyestuffs of the formula ##STR6## subsequently by tetrazotising and coupling onto 2 mol of a coupling component of the formula ##STR7## wherein Z.sub.1, Z.sub.2 = an optionally substituted amino group,

R = h or a non-ionogenic substituent,

n = an integer of 1 - 3.

Suitable coupling components (VI) are, for example, 1,3-diaminobenzene, 1-amino-3-alkylaminobenzenes, such as, 1-amino-3-methylaminobenzene, 1-amino-3-.beta.-hydroxyethylaminobenzene, 1-amino-3-carboxymethylaminobenzene, 1-amino-3-sulphomethylaminobenzene, 1,3-diamino-4-nitrobenzene, 1-amino-3-aminocarbonyl-aminobenzene, 1-amino-3-actylaminobenzene.

The new dyestuffs are suitable for dyeing and printing natural fibre materials, in particular leather. Black dyeings with good fastness properties are obtained on these materials.

28 g of 4,4'-diamino-diphenylamine-2'-sulphonic acid are tetrazotised in known manner and coupled in an alkaline medium onto 64 g of 2-amino-8-hydroxynaphthalene-3,6-disulphonic acid. The resulting diaminodisazo dyestuff is further tetrazotised and coupled onto 22 g of 1,3-diaminobenzene. The dyestuff precipitated by the addition of sodium chloride and then isolated is easily soluble in water and dyes leather black.

If equivalent amounts of 1-methyl-2,4-diaminobenzene, 1-amino-3-methylaminobenzene, 1-amino-3-.beta.-hydroxyethylaminobenzene, 1-amino-3-carboxymethylaminobenzene, 1,3-diamino-4-nitrobenzene or 1-amino-3-acetylaminobenzene are employed as end components, then black dyestuffs are obtained which are excellently suitable for dyeing leather.