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

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 H-1-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.