The coupling of 1H-4-ethoxycarbonyl-3-methyl-pyrazol-5-yl-diazonium chloride (2) with 1H-1,3-disubstituted5-pyrazolones (3), was performed in water-alcoholic solution, in the presence of sodium acetate and gave the
corresponding 1,3-disubstituted 1H-4-(1H-4-ethoxycarbonyl-3-methyl-pyrazol-5-yl)azo-5-pyrazolones (4). The structure
of the new azo dyes was confirmed by IR, VIS and NMR spectroscopy.
