Synthesis of novel tetrasubstituted thiophenes based dye using sodium a-cyanoketene dithiolates as starting materials

Purpose – The study aims to synthesise new thiophene-based dyes by an efficient method using sodium a-cyanoketene dithiolates as starting components for synthesis of tetra-substituted thiophenes, which act as a coupler for the synthesised dye. The synthesised dyes are applied for printing polyamide and polyester fabrics using the screen printing technique. Design/methodology/approach – Treatment of 1 with carbon disulfide in alkaline medium forming disodium salt 2, which act as starting point for heterocyclisation to prepare these dye stuff 7. Sodium a-cyanoketene dithiolates 2 react with two moles of phenacyl bromide derivatives, forming alkylsulfanylthiophenes which react with the diazonium salt, forming the target dyestuff. These prepared dyes are used to print polyamide and polyester fabrics by using a synthetic thickener in the printing paste using screen-printing techniques. Findings – The structure of synthesised dyes were established and confirmed for the reaction products on the basis of their el...