Synthesis and characterization of selected 4,4′-diaminoalkoxyazobenzenes

Abstract The role of the –N(CH 2 CH 2 OH) 2 group in producing a mutagenic response from 4-((3-(2-hydroxyethoxy)4-amino)phenylazo)- N , N -bis(2-hydroxyethyl)aniline has been investigated. To accomplish this goal, a group of substituted 4,4′-diaminoazobenzene dyes was synthesized, and their structures were confirmed using 1H NMR, TOF-LC-ESI mass spectrometry, and combustion analysis. Mutagenicity was determined using the standard Ames test in Salmonella strains TA98, TA100, and TA1538 with and without S9 enzyme activation. The results of this study provide evidence that the mutagenicity of the parent dye arises from the metabolic cleavage of N -hydroxyethyl groups to give the corresponding –NHCH 2 CH 2 OH and –NH 2 substituted monoazo dyes as direct-acting mutagens. All 5 of the dyes studied were mutagenic at various levels with and without S9 enzyme activation in TA1538. In addition, the results show that removing one N -hydroxyethyl group and capping both –OH groups in the parent dye did not affect mutagenicity, whereas removing both N -hydroxyethyl groups produced a strong direct-acting mutagen in all three bacterial strains. Increasing the length of the N -alkyl chain from two to three carbon atoms eliminated mutagenicity in TA98 without S9 activation.