Production of nitroanthraquinones having free or formylated amino groups

Nitroanthraquinones containing in the anthraquinone nucleus one or more free or formylated amino groups are prepared by nitrating a N,N-dialkyl - N1 - anthraquinonylformamidinium chloride with a 65-85% HNO3 at 50-100 DEG C. or 85-100% HNO3, or 60-100% HNO3 and at least 85% H2SO4 containing up to 5% free SO3, at 0-50 DEG C., with subsequent heating in an aqueous medium at a pH of 0-14 to eliminate the formamidinium chloride radical. Other groups which may be attached to the anthraquinone nucleus are alkyl, acyl, sulphonalkylamide, carboxy, thiadiazole, oxdiazole or alkoxy groups, or chlorine or bromine atoms. The nitro compounds may be reduced to the corresponding amines with sodium hydrogen sulphide in water or zinc in acetic acid.