Apparent correlation between structure and carcinogenicity of phenylenediamines and related compounds

The carcinogenicity of 23 phenylenediamines and related compounds was reviewed. An extensive analysis of the methods used indicated that the bioassays were conducted well. The data suggest that the carcinogenicity of 4-substituted 1,3-phenylenediamines is reduced substantially or eliminated completely by oxidation of one or both amine groups or by N-substitution. Oxidation of a methyl substituent on nitroaniline to a carboxyl group eliminated all carcinogenic activity. It required dichlorination to make ring-substtuted 1,4-phenylenediamine carcinogenic whereas only one chlorine atom was needed to make 1,2- and 1,3-phenylenediamine carcinogenic. While the available data suggest that as a class, 4-substituted 1,3-phenylenediamines are carcinogenic more often than ring-substituted 1,4-phenylenediamines, the type of added substituent and its position on the benzene ring also are important in exerting carcinogenic activity.