Synthesis of azobenzo[b]thiophene derivatives and their dyeing performanceon polyester fibre

Ethyl 2-amino-4,5,6,7-tetrahydrobenzo[b]thiophene-3-carboxylate was synthes ised by the reaction of cyclohexanone and sulphur with ethylcyanoacetate. T he 2-aminothiophene derivative was diazotised and coupled with various N-ar ylmaleimides to give monoazo disperse dyes. The dyeing performance of these dyes was assessed on polyester fabric. These dyes were found to give light pink to reddish pink shades with very good depth and levelness on polyeste r fabric. The dyed fabric showed fair light fastness and excellent washing, rubbing, perspiration and sublimation fastness. The dyebath exhaustion on polyester fabric was found to be good and acceptable.