Synthesis and evaluation of organic pigments.; 2. Studies of bisazomethine pigments based on planar nonmutagenic benzidine analogs

The synthesis, characterization, genotoxicity and light fastness of thio- and oxopyrimidine based bisazomethine pigments prepared from a series of nonmutagenic benzidine congeners is reported. Whereas bisazomethine pigments based on benzidine and 3,3ʹ-dimethylbenzidine were mutagenic in both the Ames assay and the Prival modification of the Ames assay, incorporation of bulky (>C2) alkyl and alkoxy groups in the 3,3ʹ- positions of the benzidine moiety gave nonmutagenic bisazomethine pigments.