Monoazo dyes and their preparation and use

A monoazo dye of formula (3)

• wherein
• R1 represents hydrogen or alkyl with 1 to 6 C atoms;
• n is 2, 3 or 4;
• A represents NR3R4, wherein R3 and R4 independently represent hydrogen;
• alkyl with 1 to 8 C atoms;
• substituted alkyl with 2 to 6 C atoms, where the substituents are selected from the group consisting of OH, OCH3, COOM and SO3M;
• aralkyl;
• aryl or substituted aryl, where the substituents are selected from the group consisting of OCH3, Cl, Br, COOM and SO3M;
• or where R3 and R4 together form a ring with or without a hetero atom;
• R2 represents alkyl with 1 to 6 C atoms;
• and
• M represents hydrogen, a metal cation or an ammonium cation, which may be substituted by one or more alkyl or substituted alkyl groups each having from 1 to 12 C atoms.