Basic azo dyestuffs of the 3-cyano-2,4,6-triamino pyridine series

An azo dyestuff of the formula ##STR40## wherein R.sup.1 represents hydrogen, alkyl or aryl or

• R.sup.1 and R.sup.2, together with B and the two nitrogen atoms to which they are bonded, form an optionally substituted 5- or 6-membered heterocyclic ring, and in this-case B represents a direct bond, --CH.sub.2 -- or --CH.sub.2 CH.sub.2 --,
• R.sup.2 and R.sup.3 independently of one another represent hydrogen, alkyl, alkenyl or aralkyl or
• R.sup.2 and R.sup.3, together with the nitrogen atom to which they are bonded, form an optionally substituted 5- or 6-membered heterocyclic ring,
• n represents 2 and
• D represents the radical of a tetrazo component of the formula ##STR41## wherein R.sup.7 -R.sup.10 independently of one another represent hydrogen, SO.sub.3 H, C.sub.1 -C.sub.4 -alkyl, C.sub.1 -C.sub.4 -alkoxy, chlorine or bromine,
• B represents C.sub.2 -C.sub.5 -alkylene which is optionally interrupted by ##STR42## wherein R represents hydrogen, or represents C.sub.1 -C.sub.4 -alkyl which is optionally substituted by chlorine, bromine, hydroxyl, cyano, C.sub.1 -C.sub.4 -alkoxy, amino and mono- and di-C.sub.1 -C.sub.4 -alkylamino, or represents C.sub.6 -C.sub.10 -aryl which is optionally substituted by fluorine, chlorine, bromine, C.sub.1 -C.sub.4 -alkyl or C.sub.1 -C.sub.4 -alkoxy, or
• B represents a radical of the formula ##STR43## wherein q represents 0, 1, 2 or 3,
• p represents 1, 2 or 3,
• (CH.sub.2).sub.p is bonded to the radical NR.sup.2 R.sup.3 and
• R.sup.17 represents hydrogen, C.sub.1 -C.sub.4 -alkyl, C.sub.1 -C.sub.4 -alkoxy, chlorine or bromine,
• Y represents a direct bond or a bridge member of the formula --CO--NH--, --CO--, --NH--CO--NH--, --CH.sub.2 --CH.sub.2 --, --CH.dbd.CH--, --CH.sub.2 --, --C(CH.sub.3).sub.2 --, ##STR44## --O--, --S--, --NH--, ##STR45## --N.dbd.N--, --NH--CO--CH.dbd.CH--CO--NH--, --NH--CO--CH.sub.2 --CH.sub.2 --CO--NH-- or ##STR46## wherein R.sup.18 represents alkyl or aryl or represents a radical of the formula ##STR47## wherein m represents 2 or 3,
• r represents 0 or 1 and
• R.sup.20, R.sup.21, R.sup.22, R.sup.23 and R.sup.24 independently of one another represent hydrogen, alkyl, alkenyl, aryl, aralkyl or cycloalkyl, or
• R.sup.21 and R.sup.22, together with the N atom to which they are bonded, form a 5- or 6-membered ring.