Estimation of azo - hydrazo tautomeric equilibrium in ortho-hydroxy-azocompounds by N.M.R.

Bekárek, Y.; Rothschein, K.; Vetešník, P.; Večeřa, M.

doi:10.1016/s0040-4039(00)75523-7

Cited by 49 publications

(11 citation statements)

References 7 publications

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“…If J is large, 15 N satellites may show up in proton spectra with 15 N in natural abundance; or measurements may be made in proton resonance of 15 N α -labelled compounds, by INEPT-type methods with 15 N enrichment, by heteronuclear multiple-quantum coherence spectroscopy, etc. 41 …”

Section: Spin-spin Couplings To Nitrogen In Azo Azoxy and Hydrazmentioning

confidence: 99%

NMRSpectroscopy of Azo, Azoxy and Hydrazo Compounds

Mason

2009

Patai's Chemistry of Functional Groups

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Introduction: Nitrogen NMR Spectroscopy 15 N and 14 N Techniques Nitrogen Shielding in Azo, Azoxy and Hydrazo Compounds Nitrogen Shielding Tensors Spin–Spin Couplings to Nitrogen in Azo, Azoxy and Hydrazo Compounds

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Section: Spin-spin Couplings To Nitrogen In Azo Azoxy and Hydrazmentioning

confidence: 99%

NMRSpectroscopy of Azo, Azoxy and Hydrazo Compounds

Mason

2009

Patai's Chemistry of Functional Groups

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“…Aryl azo compounds are well known to exist as tautomers between the hydroxyazo and quinonhydrazo forms, and this equilibrium has been well studied by IR and NMR methods (169)(170)(171). Baram and coworkers (168,172) examined some new gossypol azo compounds they had synthesized by using IR and UV spectroscopy as well as molecular modeling (168,172).…”

Section: Gossypol Reactionsmentioning

confidence: 99%

Reaction chemistry of gossypol and its derivatives

Kenar

2006

J Americ Oil Chem Soc

108

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Gossypol, a complex polyphenolic compound, is a naturally occurring highly colored yellow pigment found in the small intercellular pigment glands in the leaves, stems, roots, and seed of cotton plants. In cottonseed, gossypol contributes to its toxicity and therefore it is regarded as an unwanted processing component. It was not until its antitumor and male infertility activities were discovered that gossypol was considered as a valueadded natural product from cottonseed with useful physiological and chemical properties. These serendipitous discoveries created much excitement, and an enormous amount of research on gossypol has ensued. Since then, much research has focused on the preparation of suitable gossypol derivatives for medicinal applications. This review summarizes current knowledge about gossypol, its stereochemistry, tautomerism, and the many varied reactions the gossypol molecule can undergo.

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“…Following the fact that the proton exchange between nitrogen and oxygen atoms in azodyes is fast on the NMR time scale and, thus, only one set of signals is always observed in NMR spectra (NMR data of both individual tautomers are not known) [10,11], he based the analysis on compounds 2 and 3 as models for the pure keto tautomer of 1. The assumption is based on previous NMR studies of the tautomerism of 2, showing that only 2k is presented in CDCl 3 [12] and in DMSO-d 6 [13]. This was also confirmed by the study of a 4-fluoroderivative [14].…”

Section: Introductionmentioning

confidence: 64%

4-Carboxyl-2,6-dinitrophenylazohydroxynaphthalenes tautomerism NMR re-explained and other methods verified

et al. 2017

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In two consecutive studies the tautomerism in 4-((2-hydroxynaphthalen-1-yl)diazenyl)-3,5dinitrobenzoic acid and the structurally similar 1-((2-nitrophenyl)diazenyl)naphthalen-2-ol has been considered from viewpoint of theoretical chemistry, UV-Vis spectroscopy and NMR.Although the theoretical data (at M062X level) show that both compounds exist only as a keto tautomer, the experiment proves existence of the enol form. The difference in the results obtained by UV-Vis spectroscopy and NMR requires a deeper consideration and verification of the NMR approach, which is based on using model compounds to provide the NMR signal pattern of individual tautomers.

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Estimation of azo - hydrazo tautomeric equilibrium in ortho-hydroxy-azocompounds by N.M.R.

Cited by 49 publications

References 7 publications

NMRSpectroscopy of Azo, Azoxy and Hydrazo Compounds

NMRSpectroscopy of Azo, Azoxy and Hydrazo Compounds

Reaction chemistry of gossypol and its derivatives

4-Carboxyl-2,6-dinitrophenylazohydroxynaphthalenes tautomerism NMR re-explained and other methods verified

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