X-ray diffraction and spectroscopic verification of dimerization in hexasubstituted para-nitrosophenols

Alemasov, Y.A.; Slaschinin, D.G.; Tovbis, M. S.; Кирик, С. Д.

doi:10.1016/j.molstruc.2010.10.040

Cited by 11 publications

(2 citation statements)

References 17 publications

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“…Crystallographic studies of substituted nitrosobenzenes and calculations both confirm the generality of this phenomenon (Table ). The table omits structures with significant disorder and R factors greater than 6%, because their low precision does not allow detailed analysis of geometric features. − Moreover, structures of electron-rich heteroaromatic nitroso compounds are also omitted, because their key features resemble those of nitrosobenzene derivatives and they add little to the basic understanding of how substituents interact with the nitroso group. Specific electron-rich heteroaromatic nitroso compounds for which structural data are available include derivatives of benzothiazole, benzothiophene, imidazopyrimidine, indolizine, and pyrazole. − In addition, the structures of over 60 related derivatives of 5-nitrosopyrimidine have been published in the last two decades. − The marked interest in this family of compounds mainly stems from their biological activity , and their use as intermediates in the synthesis of biologically relevant heterocycles. − …”

Section: Structures Of Nitrosoarenes and Their Azodioxy Dimersmentioning

confidence: 99%

Dimerization of Aromatic C-Nitroso Compounds

2016

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Aromatic C-nitroso compounds (Ar-N═O) and related species have a rich chemical history, and they continue to interest researchers in many fields. Among the most distinctive and puzzling properties of these compounds is their ability to dimerize reversibly to form azodioxy compounds. The present review subjects this intriguing phenomenon to comprehensive analysis. All aspects of the subject are examined in detail, including the structures of monomeric and dimeric forms, the mechanism of dimerization, features that favor or disfavor dimerization, thermodynamic and kinetic factors, dimerization under specific conditions (including in solution, in the solid state, and on surfaces), and the special associative behavior of dinitroso and polynitroso compounds. By summarizing the current state of knowledge, the review promises to spur further advances in the evergreen field of C-nitroso chemistry, including the discovery of new ways to exploit the reversible dimerization of nitrosoarenes.

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Section: Structures Of Nitrosoarenes and Their Azodioxy Dimersmentioning

confidence: 99%

Dimerization of Aromatic C-Nitroso Compounds

2016

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“…We recently showed by the X-ray powder diffraction method that these compounds, unlike all known nitrosophenols, exist as dimers like azodioxides [2]. Hydrogenation of such polysubstituted nitrosophenols makes it possible to readily obtain the corresponding exhaustively substituted aminophenols [3] which are used in the synthesis of modern antiarrhythmic agents [4].…”

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Acidity of new exhaustively substituted p-nitrosophenols

2011

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SHORT COMMUNICATIONSA number of exhaustively substituted p-nitrosophenols I having ester groups in the ortho positions with respect to the hydroxy group were reported in [1].Ia, 5.33 ± 0.01; Ib, 5.35 ± 0.04; Ic, 5.35 ± 0.03; Id, 5.38 ± 0.04; Ie, 5.58 ± 0.03; If, 5.42 ± 0.03; Ig, 5.64 ± 0.06.These data show that the acidity constant almost does not depend on the alkyl group in the ester fragments of exhaustively substituted p-nitrosophenols. We can only note some tendency of pK a to increase with increase in the size of the alkyl group. REFERENCES 1. Belyaev, E.Yu., Tovbis, M.S., and El'tsov, A.V., Zh. Org. Khim., 1978Khim., , vol. 14, p. 2375 ISSN 1070-4280, Russian Journal of Organic Chemistry, 2011, Vol. 47, No. 9, p. 1432. © Pleiades Publishing, Ltd., 2011. Original Russian Text © D.G. Slashchinin, A.A. Kukushkin, M.S. Tovbis, 2011, published in Zhurnal Organicheskoi Khimii, 2011, Vol. 47, No. 9, p. 1406 DOI: 10.1134/S1070428011090296We recently showed by the X-ray powder diffraction method that these compounds, unlike all known nitrosophenols, exist as dimers like azodioxides [2]. Hydrogenation of such polysubstituted nitrosophenols makes it possible to readily obtain the corresponding exhaustively substituted aminophenols [3] which are used in the synthesis of modern antiarrhythmic agents [4]. On the other hand, the acidity of compounds I was not studied. Only the acidity constant of diethyl 2-hydroxy-4,6-dimethyl-5-nitrosobenzene-1,3-dicarboxylate (Ib) was reported (pK a 5.35 ± 0.04) [5].We now report on the acidity of a series nitrosophenols Ia-Ig and its relation to the nature of alkyl group in the ester moieties. The acidity constants were determined by spectrophotometry [6] at 25.0 ± 0.1°C using citrate buffer [7]. The pK a values are as follows:

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Cyclocondensation of 2‐Hydroxyimino‐1‐(naphthalen‐1‐yl)butane‐1,3‐dione with Alkyl Hydrazines Leading to Substituted 4‐Nitrosopyrazoles

et al. 2020

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Cyclocondensation of 2‐(hydroxyimino)‐1‐(naphthalen‐1‐yl)butane‐1,3‐dione with alkyl hydrazines leading to new 1‐alkyl‐3(5)‐methyl‐5(3)‐(naphthalene‐1‐yl)‐4‐nitrosopyrazoles is described. 8 previously unknown N‐alkyl‐4‐nitrosopyrazoles with a 1‐naphthalene substituent at the 3 or 5 position of the pyrazole ring were obtained as a result. It was found that yields of naphthyl‐substituted pyrazoles with N‐alkyl groups near the naphthalene substituent were significantly lower than for 3‐(naphthalen‐1‐yl)‐substituted pyrazoles. Particular yields of pairwise formed isomeric nitrosopyrazoles were associated with the different electrophilicity of the two carbonyl groups of the initial diketone. Using quantum chemical calculations by the DFT method B3LYP−D3/6‐311G(d,p), the potential energies of the various conformers were estimated to draw a conclusion about the preferred attack of alkyl hydrazine on the carbonyl group, associated with the naphthalene ring. 1H NMR and 2D 1H‐13C HSQC spectra of the compounds confirmed this direction of the reaction. The crystal structures of the synthesized compounds were established by X‐ray powder diffraction technique. Crystal structure data were in agreement with quantum chemical calculations.

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X-ray diffraction and spectroscopic verification of dimerization in hexasubstituted para-nitrosophenols

Cited by 11 publications

References 17 publications

Dimerization of Aromatic C-Nitroso Compounds

Dimerization of Aromatic C-Nitroso Compounds

Acidity of new exhaustively substituted p-nitrosophenols

Cyclocondensation of 2‐Hydroxyimino‐1‐(naphthalen‐1‐yl)butane‐1,3‐dione with Alkyl Hydrazines Leading to Substituted 4‐Nitrosopyrazoles

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