Synthesis of a new series of thiazole and pyrazole azo dye systems for dyeing synthetic fibers

Two series of azo dye systems are considered, namely, 2‐amino‐arylazo‐4‐phenylthiazole axo dye systems 4a,b,c,d,e, and 3‐methyl‐1‐phenylpyrazolone azo dye systems 8a‐d. The shifts of ultraviolet‐visible absorption maxima affected by the structural configuration of the thiazole and pyrazole dye systems are investigated. The structural effects of the polyfunctionaIly substituted thiazole and pyrazole dye systems on the intensity of colour and fastness properties of the dyed fabrics are also discussed. The data of these studies are listed.