Synthesis of some 4-arylazo-3-hydroxythiophene disperse dyes for dyeing polyester fabrics

A series of novel 4-arylazo-3-hydroxythiophene disperse dyes was synthesized by heterocyclization of ethyl 2-arylhydrazono-2-phenylthiocarbamoyl acetates with a variety of α-halogenated reagents. The structures of the synthesized dyes were confirmed by UV-Vis, IR, ¹H NMR, and MS spectroscopic techniques and elemental analysis. The dyes were applied to conventional polyester fabric by high temperature exhaust dyeing. These dyes were found to give orange to reddish-violet shades with very good depth, levelness, and brightness on polyester fabric. The dyed fabric showed moderate to good light fastness and very good fastness to washing and perspiration. Also the position of color in CIELAB coordinates (L^*, a^*, b^*, H^*, and C^*) was assessed.