A novel synthesis of 1‐oxo‐thieno[3’,2’‐3,4] pyrazolo[1,2‐a] pyrazole azo dye systems for dyeing of synthetic and modified cellulose fibers Available to Purchase

A new series of the title pyrazole azo dye systems has been synthesized. The new dyes are applied on nylon and cellulose acetate fibers to give dyed fabrics with excellent properties of colour intensity and fastness properties. The physical and spectral data of the investigated dyes are illustrated. The shifts of ultraviolet‐visible absorption maxima affected by the structural configuration of the pyrazole dye systems are investigated. The structural effects of the polyfunctionally substituted pyrazole dye systems on the intensity of colour and fastness properties of the dyed fabrics are discussed. The data of these studies are listed. The colour shades of the synthesized dyes on nylon and acetate fabrics are indicated.