Synthesis and mutagenic properties of direct dyes from 4,4′‐diamino‐p‐terphenyl and 4,4′‐diamino‐p‐quaterphenyl

Disazo direct dyes were synthesised using bis‐diazotisation and coupling reactions involving 4,4′‐diamino‐p‐terphenyl and 4,4′‐diamino‐p‐quaterphenyl. The formation of the target dyes was confirmed by electrospray mass spectrometry and their mutagenicity was examined in the Salmonella microsome assay using TA98 and TA100. While most of these dyes were clearly non‐mutagenic, results from the Prival modification of the standard assay showed that Congo Red and its homologue derived from 4,4′‐diamino‐p‐terphenyl were clearly mutagenic.