Dyestuffs of the formula ##STR1## wherein R.sub.1 is hydrogen or a low-molecular alkyl group, R.sub.2 is hydrogen, a low-molecular alkyl group, an aryl radical or the radical of an organic dyestuff containing sulpho groups, and R.sub.1 and R.sub.2 together with the nitrogen atom can form a ring, X.sub.1 and X.sub.2 are hydrogen, a sulpho group or the --N.dbd.N--K radical, wherein K is the radical of a coupling component and, if one X is the --N.dbd.N--K radical, the other X is a sulpho group, and the benzene ring A can contain further substituents.