Abstract: Compounds of the formula (I) ##STR1## in which R.sub.1 and R.sub.2 are identical or different and are hydrogen, C.sub.1 -C.sub.6 -alkyl, C.sub.6 -C.sub.10 -aryl, (C.sub.6 -C.sub.10)-aryl-(C.sub.1 -C.sub.6)-alkyl or (C.sub.1 -C.sub.6)-alkyl-(C.sub.6 -C.sub.10)-aryl, it being possible for the alkyl and/or aryl radicals to be substituted by hydroxyl, C.sub.1 -C.sub.6 -alkoxy, C.sub.6 -C.sub.10 -aryloxy or halogen,with the proviso that R.sub.1 and R.sub.2 are not simultaneously hydrogen,R.sub.3 is a radical of the formula (II) or (III) ##STR2## in which Y and R.sub.5 are as defined in the description, are valuable colorants for the mass coloring of polymers, in electrophotographic toners and developers, in powder coating materials and in ink-jet inks.