Synthesis of several new pyridine‐2(1H) thiones containing an arylazo function and their applications in textile printing

Abstract

Purpose To synthesise several new pyridine‐2(1H)thione containing an arylazo function and their applications in textile printing. Design/methodology/approach To prepare substituted 5‐arylazopyridine‐2(1H)thione by the coupling of diazonium salts of aniline derivatives with dibenzoyl methane (1,3‐diphenyl‐1,3‐propanedione) to form arylhydrazone of dibenzoylmethane which react with cyanothioacetamide in boiling ethanolic sodium ethoxide to yield the 5‐arylazo‐2(1H)‐pyridinethione derivatives. The printing properties by screen printing or transfer printing technique of these dyes are reported by using sodium alginate as thickening agent. Findings The structure of 5‐arylazopyridine‐2(1H)thione dyes were established and confirm for the reaction products on the basis of their element analysis and spectral data (MS, IR and 1 H‐NMR). The suitability of the prepared dyestuffs for either heat transfer printing or traditional printing on polyester and nylon 6 fabrics has been investigated. The prints obtained from dyes possess high‐colour strength as well as good overall fastness properties. Research limitations/implications Synthesis of azo dyes containing pyridinethiole moiety has never been reported in textile printing. Practical implications Production of simple and less costly dyes. Originality/value 5‐arylazo pyridine‐2(1H)thione, the result of our work aimed to define the scope of and limitation of our procedures for the synthesis of novel 5‐arylazopyridine‐2(1H)thione.