Disazo dyestuffs containing a thiazole central component

Disazo-thiazole dyestuff, which in the form of the free acid corresponds to the formula ##STR17## wherein R.sub.1 denotes hydrogen, methyl, ethyl, phenyl, or phenyl substituted by chlorine, methyl, methoxy, ethoxy or nitro;

• R.sub.17 and R.sub.18 denotes hydrogen, chlorine, bromine, cyano, C.sub.1 -C.sub.4 -alkyl, C.sub.1 -C.sub.4 -alkoxy, trifluoromethyl, phenoxy, C.sub.1 -C.sub.4 -alkylsulphonyl, phenylsulphonyl, benzylsulphonyl, carboxamide, sulphonamide, mono- or di-substituted carboxamide, or mono- or di-substituted sulphonamide wherein the substituents are C.sub.1 -C.sub.4 -alkyl, .beta.-hydroxyethyl, benzyl, phenyl or phenethyl;
• R.sub.19 denotes hydrogen, C.sub.1 -C.sub.4 -alkyl, chlorine or bromine;
• K denotes ##STR18## wherein R.sub.3 and R.sub.4 denote C.sub.1 -C.sub.4 -alkyl, benzyl, 2-phenylethyl, or C.sub.1 -C.sub.4 -alkyl which is substituted by C.sub.1 -C.sub.4 -alkoxy, phenoxy, hydroxyl, cyano, chlorine, methylcarbonyloxy, ethylcarbonyloxy, methoxycarbonyloxy or ethoxycarbonyloxy;
• R.sub.5 denotes hydrogen, methyl, ethyl, methoxy, ethoxy, chlorine or C.sub.1 -C.sub.3 -alkylcarbonylamino;
• R.sub.6 denotes hydrogen, C.sub.1 -C.sub.4 -alkyl, C.sub.1 -C.sub.4 -alkoxy, chlorine or bromine;
• R.sub.20 and R.sub.21 denote hydrogen, C.sub.1 -C.sub.4 -alkyl, chlorine or bromine;
• R.sub.8 denotes hydrogen, C.sub.1 -C.sub.4 -alkyl, or phenyl;
• and
• R.sub.9 denotes hydrogen, C.sub.1 -C.sub.4 -alkyl, or C.sub.1 -C.sub.4 -alkyl substituted by hydroxyl, cyano, carboxyl, or carboxamide.