Water-soluble phenylazoaminonaphthol sulphonic acid dyestuffs

A water-soluble monoazo dyestuff which, in the form of the free acid, corresponds to the formula wherein R1 denotes alkyl which can be mono-substituted by chlorine, hydroxyl, C1 to C4 alkoxy, cyano, phenyl or tolyl, cyclohexyl which can be optionally substituted by C1-C4 alkyl, phenyl, C1-C4-alkyl phenyl, chlorophenyl, bromophenyl, trifluoromethylphenyl or naphthyl, alkenyl or benzenesulphonyl which can be substituted by fluorine, chlorine, bromine, trifluoromethyl, C1-C4-alkyl or C1-C4-alkoxy, R2 denotes hydrogen, C1-C4-alkyl which can be substituted by hydroxyl, cyano, formylamino, C1-C4 alkylcarbonylamino or benzoylamino which in turn can be substituted by methyl, chlorine, bromine or trifluoromethyl; cyclohexyl or phenyl which can be substituted by C1-C4 alkyl, C1-C4-alkoxy, chlorine, bromine or trifluoromethyl and R3 denotes hydrogen or C1-C4-alkyl and a process for the preparation of such water-soluble mono-azo dyestuff. The dyestuffs according to the invention are suitable for dyeing natural and synthetic fibre materials, for example for dyeing wool or polyamide fibres, in level, deep red to violet shades with very good fastness to light, wet processing and perspiration.