Novel synthesis of heteroarylazopyrazolones and their application as disperse dyes via AlCl 3 -catalyzed diazocoupling of 1-aryl/heteroaryl-3-methyl-1 H -pyrazol-2-in- 5-ones in aqueous medium

AlCl 3 -catalyzed diazocoupling of l-aryl/heteroaryl-3-methyl-1H-pyrazol-2-in-5-ones 1 in water with different aryl/heteroaryldiazonium salts affords the corresponding heteroarylazopyrazolones 2 as colored products with high yields. These dyes have been characterized by UV-Vis, FT-IR and 'H NMR spectroscopic techniques and elemental analysis. Cotton, wool, silk and polyesters fabrics have been dyed and their photostability and color fastness identified.