Novel heterocyclic disazo dyes containing pyrazole and phenylpyrazole. part 1: Synthesis, characterization, solvent polarity and acid-base sensitive characteristics

Article abstract of DOI:10.1016/j.molstruc.2021.129960

A series of diazotised aniline and aniline derivative compounds were reacted with solution of malononitrile in pyridine at 0–5 °C were obtained 1a-1m compounds. Then 4-arylazo-3,5-diamino-1H-pyrazole (2a-2m) derivatives were synthesized by coupling arylazo malononitrile compounds with hydrazine. Finally, the synthesized pyrazole derivative 2a-2m compounds were again diazotised. By reacting these diazotised compounds with 3-amino-5?hydroxy-1-phenylpyrazole, the new thirteen heterocyclic disazo dyes (3a-3m) were joined the dye literature and the dye industry. The structures of these newly synthesized compounds were characterized using elemental analysis and spectroscopic methods such as Fourier transform infrared spectroscopy-Attenuated total reflectance (FT-IR-ATR), ¹H-Nuclear magnetic resonance (¹H NMR) spectroscopy and mass spectroscopy. Then solvatochromic properties and solvent effect in dimethyl sulfoxide, dimethyl formamide, acetonitrile, acetic acid, methanol and chloroform were investigated. In addition, the effects of organic and inorganic acids and bases on the absorption spectra of the compounds and the substituent effect of the phenyl ring-bound groups were investigated.