15N, 13C and 1H NMR spectra and azo-hydrazone tautomerism of some phenylazo compounds derived from 1,3- and 1,5-dihydroxynaphthalene

Lyčka, Antonı́n; Vrba, Z.; Vrba, M

doi:10.1016/s0143-7208(00)00062-0

Cited by 26 publications

(17 citation statements)

References 11 publications

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“…Tautomeric hydrazone (-NH) and tautomeric imine (-NH) were recorded as broad singlets at 14.28-14.06 ppm and 8.51-7.28 ppm, respectively. It was reported that the hydrazone -NH proton resonance appears approximately between 13.0-16.0 ppm, in oand p-hydroxyazo dyes [28,29]. Dyes 2-4, 8, 14 and 15 did not show the tautomeric hydrazone peak.…”

Section: H Nmr and Ir Studymentioning

confidence: 91%

Synthesis, characterization and spectroscopic properties of some new phenylazo-6-aminouracil

Seferoğlu

Ertan

2008

Open Chemistry

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Abstract:In this study, a series of new 5-phenylazo-6-aminouracil dyes were prepared by linking m-,p-nitroaniline, m-,p-chloroaniline, m-,p-anisidine, m-,p-toluidine, m-,p-cyanoaniline, p-ethoxyaniline, p-phenoxyaniline, p-ethylaniline, p-acetamidoaniline, p-acetylaniline, p-carboxyaniline and aniline to 6-aminouracil. The prepared dyes were characterized by UV-vis, FT-IR, 1 H NMR spectroscopic techniques and elemental analysis. The effect of acid and base upon the UV-vis spectra of these dyes were investigated. In addition, the solvatochromic behaviors and substituent effects in various solvents were evaluated. © Versita Warsaw and Springer-Verlag Berlin Heidelberg.

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Section: H Nmr and Ir Studymentioning

confidence: 91%

Synthesis, characterization and spectroscopic properties of some new phenylazo-6-aminouracil

Seferoğlu

Ertan

2008

Open Chemistry

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“…Meanwhile, the 1 H NMR spectra of the dyes with homocyclic diazo components 5 ‐ 14 showed two signals, at 17.67‐15.32 ppm and 17.19‐14.81 ppm. These two highly deshielded singlets can be attributed to hydrazone NH protons . Further evidence for this is provided by observing the 1 H NMR spectra of the 15 N phenylhydrazone derivatives of some similar azo heterocycles that were reported to show two doublets centred at similar regions, with 1 J N‐H = 93‐100 Hz indicating that the proton is attached to a nitrogen atom.…”

Section: Resultsmentioning

confidence: 94%

Aryl and heteroaryl azo dyes derived from 6, 8‐dichloro‐4‐hydroxyquinolin‐2 (1H)‐one: synthesis, characterisation, solvatochromism and spectroscopic properties

Rufchahi

Gilani

2019

Coloration Technology

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In this research study, 6, 8‐dichloro‐4‐hydroxyquinolin‐2(1H)‐one was prepared by the thermal cyclocondensation of 2‐(2, 4‐dichlorophenylcarbamoyl) acetic acid or N, Nʹ‐bis(2,4‐dichlorophenyl)malonamide at 140‐150°C in polyphosphoric acid, resulting in a yield of 48%. This compound was then coupled with a series of diazonium salts derived from aromatic and heteroaromatic amines for synthesis of the corresponding azo dyes. The structures of the compounds were confirmed using elemental analysis as well as ultraviolet‐visible, Fourier Transform‐infrared and proton nuclear magnetic resonance spectroscopy. The effects of organic solvents with different polarities, pH values and substituents of the diazotising components on the maximum absorption wavelength of the colorants were discussed and evaluated in detail. The acidity constants (pKa) of the dyes were also determined using the spectrophotometric method in an ethanol‐water mixture (80:20, v/v) at 20‐23°C.

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“…Unfortunately, this information alone is questionable and open to criticism to distinguish between the azo and hydrazone tautomers ( An initial clue for assigning the tautomeric state was provided by the 1 HNMR spectra indicate that compounds under scrutiny exist as the hydrazone form (D) rather than as an equilibrium mixture of several tautomeric species. It was reported that the hydrazone NH proton resonance appears approximately between 13.0 and 16.0 ppm, in o-and p-hydroxyazo dyes [25,26]. Also, the spectral data do not show any more high field signals around 12.4 ppm which is reported for the O-H of form (A),(B) or around 5.5 ppm for CH of tautomeric form C of the annulated similar compounds, respectively [27].…”

Section: Synthesis and Tautomeric Structurementioning

confidence: 79%

Synthesis, Structure Elucidation and Application of Some New Azo Disperse Dyes Derived from 4-Hydroxycoumarin for Dyeing Polyester Fabrics

Metwally¹,

Bondock²,

El-Desouky³

et al. 2013

CHEMISTRY

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As a part of our ongoing interest in disperse dyes and task specific azo dyes with better dyeing properties, we synthesized a series of 3-aryl(hetaryl)hydrazono-2,4-chromandiones 4a-k via Coupling of 4-hydroxycoumarin with diazotized aniline derivatives. Structures of the synthesized compounds have been investigated by means of UV, IR, 1 H-NMR and mass spectroscopy in order to elucidate their tautomeric and isomeric structures. The results of such spectral data indicated that compounds 4a-k exist predominantly in the hydrazo structure (D) as a mixture of Z and E-isomer with ratio ~ 84.5:15.5. Finally, the prepared dyestuffs 4a-k were applied as disperse dyes for dyeing polyester fabrics and their fastness properties were evaluated. Also, the position of color in CIELAB coordinates

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15N, 13C and 1H NMR spectra and azo-hydrazone tautomerism of some phenylazo compounds derived from 1,3- and 1,5-dihydroxynaphthalene

Cited by 26 publications

References 11 publications

Synthesis, characterization and spectroscopic properties of some new phenylazo-6-aminouracil

Synthesis, characterization and spectroscopic properties of some new phenylazo-6-aminouracil

Aryl and heteroaryl azo dyes derived from 6, 8‐dichloro‐4‐hydroxyquinolin‐2 (1H)‐one: synthesis, characterisation, solvatochromism and spectroscopic properties

Synthesis, Structure Elucidation and Application of Some New Azo Disperse Dyes Derived from 4-Hydroxycoumarin for Dyeing Polyester Fabrics

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