... in the azo-coupling reaction with some aniline-based diazonium salts, so as to prepare seven new mono-heterocyclic azo dyes. The structures of the compounds were confirmed using mass spectroscopic technique. Fourier transform infra red (FT-IR) and 1H proton nuclear magnetic resonance (1H NMR) and carbon-13...

... in acetic acid, ethanol, chloroform, acetonitrile, dimethyl formamide and dimethyl sulfoxide and correlated with the nature of the solvents and substituents. The effects of varying pH on the absorption wavelengths of the azo dyes were also studied. In addition, the acidity constants (pKa) of the dyes were...

..., multiple applications and spectral properties. Azo dyes Photophysical properties Protic organic solvents Solvatochromism Ureido/thioureido benzimidazoles UV-Vis spectroscopy (E)-N-(4-Nitrophenyl)-1H-benzo[d]imidazole-2-carbohydrazonoyl bromide (3a) Brown crystals; Yield: 57% (1.02...

... for C₂₅H₁₉N₅O₂ (421.45): C, 71.25; H, 4.54; N, 16.62 per cent. Found: C, 70.89; H, 4.21; N, 16.25 per cent (Scheme 1). Antimicrobial activity Pyrazolo[3,4-b]pyridine Azo dyes Dyed fabrics Fastness properties Pyridine Thiophene Thiophene and its derivatives constitute one of the major...

...Esmail Rezaei-Seresht; Aboulfazl Salimi; Behnam Mahdavi Purpose The purpose of this paper is synthesis and evaluation of antioxidant and antibacterial activities of a series of new azo dyes derived from 4-aminostilbene. Design/methodology/approach First, the starting material 4-aminostilbene...

... of heterocyclic azo dyes such as 4‐aryl‐3‐cyano‐2‐aminothiophenes (Yen et al., 2004a, b, c) and polysubstituted‐5‐(2‐pyrido‐5‐yl and 5‐pyrazolo‐4‐yl)azo‐thiophene derivatives (Yen et al., 2004a, b, c). In addition the synthesis of 4‐(p‐substituted) phenyl‐2‐(2‐pyrido‐5‐yl and ‐pyrazolo‐4‐yl...

...M.H. Helal; G.H. Elgemeie; D.M. Masoud Purpose This paper aims to synthesize some new heterocyclic disperse azo dyes and their application in dyeing of polyester and polyamide fabrics. Design/methodology/approach Pyrazolopyrimidine derivatives containing arylazo function by the reaction of 3,5...