Direct Dyes Derived from 4,4'-Diaminobenzanilide Synthesis, Characterization and Toxicity Evaluation of a Disazo Symmetric Direct Dye

The synthesis of a new symmetric disazo direct dye containing the non--carcinogenic 4,4'-diaminobenzanilide as the middle component and salicylic acid as the coupling component is presented. The synthesized dye is an analog of the benzidine based dye C. I. Direct Yellow 1 (C. I. 22,250) and was analyzed by thin layer chromatography (TLC), electronic spectra (VIS) and mass spectroscopy (FAB-MS). The coloristic and fastness properties of the synthesized dye were determined and compared with those of C. I. Direct Yellow 1. The toxicities of the dye and of its precursors were evaluated by biological tests, using the process of metamorphosis in the marine hydrozoon Hydractinia echinata. The concentrations (termed MRC50) at which the synthesized dye and its precursors antagonize metamorphosis induction were determined.