Sulfo containing monoazo dyestuffs containing a benzthiazole diazo moiety and an N-benzylamino anilino coupling component

Azo dyestuffs of formula wherein R1 denotes hydrogen, C1-C4 alkyl, Cl, Br, -OCH3, -OC2H5, -NO2, -CN, -SCN, -SO2CH3, -SO2C2H5, -SO3H, -SO2NX2 (X=H or CmH2m+1 with m = 1-4) or -COOCnH2n+1 (n = 0-4); R2 represents hydrogen, CH3, C2H5, -OCH3, -OC2H5, Cl, Br, or the grouping -NHCOCnH2n+1 (n = 0-4); R3 denotes hydrogen, OCH3, OC2H5, CH3 or C2H5; R4 represents CnH2n+1 (n = o-4), or CH2CH2SO3H; R5 represents hydrogen or a sulphonic acid group, and p is 1 or 2, WITH ONLY ONE OF THE RESIDUES R1, R4 and R5 representing or containing a sulphonic acid group. The dyestuffs are suitable for dyeing nitrogen-containing materials especially for dyeing synthetic polyamide and polyurethane fibers. The dyestuffs are very well absorbed on the polyamide fibers both from an acid dyebath and from a neutral dyebath. In one example synthetic polyamide fibers are dyed in clear shades having good to very good fastness properties.