Synthesis and Characterization of Some Azo-heterocycles Incorporating pyrazolopyridine Moiety as Disperse Dyes

Document Type : Original Article


Dyeing, Printing and Auxiliaries Department, Textile Research Division, National Research Centre, Cairo 12622, Egypt


In this research paper, we used 3-aminopyrazolo[3,4-b]pyridine as key intermediate for the synthesis of some pyrazolopyridine azo compounds. The key starting fused heterocyclic 3-aminopyrazolo[3,4-b]pyridine is prepared by the reaction of 2-chloro-4,6-dimethylnicotinonitrile with hydrazine hydrate. The azo-coupling reaction of the pyrazolopyridinyl diazonium salt with a variety of coupling agents such as β-naphthylamine, β-naphthol, thiazole, and aniline derivatives afforded the corresponding arylazopyrazolo[3,4-b]pyridine derivatives in relatively high yield. The chemical structures were established using FT-IR, elemental analysis (C, H, N), and 1H-NMR, 13C-NMR. The prepared arylazopyrazolo[3,4-b]pyridine disperse dyes were applied to dye polyester garments to provide good color fastness properties.


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