Potentiometric and 1H NMR study of the interaction of hypoxanthine and inosine with H+, Cu(II), and Zn(II)

Tauler, Romà; Cid, Judith; Casassas, E.

doi:10.1016/0162-0134(90)80026-t

Cited by 23 publications

(7 citation statements)

References 21 publications

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“…With regard to the angles of the CNC groups in the imidazolic ring and for the six tautomers, those N-protonated CNC groups always show higher angles than the deprotonated ones. This could be associated with a higher sp character for the atomic orbitals of the protonated N atoms, and a higher p -contribution in the corresponding atomic orbitals of the deprotonated N atoms. For the pyrimidinic ring, this same structural pattern is observed in the N(1)−H/N(7)−H and N(1)−H/N(9)−H tautomers.…”

Section: Resultsmentioning

confidence: 99%

“…In the purines catabolism, it is a substrate of the metalloenzyme xanthine oxidase in the production of uric acid 1b 1d, from them, the N atoms are the favorable metallic coordination sites, the nature depending on the experimental conditions. For the neutral coordinated hypoxanthine, two ketonic tautomeric forms have been detected experimentally, the N(1)−H/N(9)−H and the N(1)−H/N(7)−H, which have also been suggested as the predominant tautomers in aqueous and dimethyl sulfoxide (DMSO) solutions …”

Section: Introductionmentioning

confidence: 99%

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Density Functional Study of the Neutral Hypoxanthine Tautomeric Forms

Costas

Acevedo‐Chávez

1997

J. Phys. Chem. A

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The energetic stability and structural and electronic properties of all the ketonic and enolic tautomers of neutral hypoxanthine are studied at the level of density functional theory. We also study the influence of temperature on the tautomeric equilibria and the IR vibrational spectrum of this heterocycle in the gas phase in terms of the contributions of several tautomers. We found that the two N(1)-H ketonic tautomers of hypoxanthine are the energetically most stable ones and represent the main contribution to the experimental IR spectrum. The calculated properties and the potential chemical behavior suggested for hypoxanthine from the theoretical study are in remarkable agreement with the experimental data reported up to date.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Density Functional Study of the Neutral Hypoxanthine Tautomeric Forms

Costas

Acevedo‐Chávez

1997

J. Phys. Chem. A

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“…Thus, ultraviolet spectra in aqueous solution suggest that H19 is predominant, but information gathered from NMR data is equivocal 34c. Protonation of hypoxanthine occurs at the imidazole ring, 34d, and a recent study seems to suggest that protonation probably occurs at N7, which indicates that H19 is the predominant tautomer. 13 C-NMR data in dimethylsulphoxide solution indicates that the population of H17 is around 58% .…”

Section: Discussionmentioning

confidence: 99%

Tautomerism of Xanthine Oxidase Substrates Hypoxanthine and Allopurinol

1996

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The tautomerism of neutral hypoxanthine and allopurinol in the gas phase and in aqueous solution has been examined by theoretical methods. The tautomeric equilibrium in the gas phase was studied from semiempirical and ab initio quantum mechanics (QM) and also from density functional theory (DFT) calculations. Electron correlation effects were included in ab initio computations at the Møller−Plesset level, and DFT calculations were carried out using the Becke3−Lee−Yang−Parr functional. The influence of the solvent was examined from self-consistent reaction field calculations performed with different continuum models. The results provide a detailed picture of the tautomerism of these biologically relevant compounds. Comparison with available experimental data provides support for the quality of results derived from theoretical computations. Inspection of the most stable tautomeric forms allows discussion of the functional implications of tautomerism for recognition and binding of these molecules to xanthine oxidase.

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“…First, all the compounds structures were drawn using Gauss View 03 and optimized in GAUSSIAN09. The tautomers were also optimized in solvents according to the polarisable continuum method of Tomasi and co-workers, which exploits the generating polyhedra procedure [22][23][24][25][26] to build the cavity in the polarisable continuum medium, where the solute is accommodated. Atomic charges in all the structures were obtained using the Natural Population Analysis (NPA) method within the Natural Bond Orbital (NBO) approach 27 .…”

Section: Methodsmentioning

confidence: 99%

Theoretical Survey on Tautomerism of Thioguanine Tautomers by Polarisable Continuum Method (PCM)

Heidarnezhad¹,

Heidarnezhad²,

Ганиев³

et al. 2013

Orientjchem.

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Computational calculations at B3LYP/CC-PVDZ level were employed in the study of tautomers of Thioguanine (TG) in the gas phase and selected solvents such as benzene , tetrahydrofuran (THF), methanol, Dimethyl sulfoxide (DMSO) and water using PCM model. All tautomers are optimized at this level. In addition, stability of the tautomers in different solvents shows interesting results. In the gas phase, benzene and THF, TG1 form is more stable than the other forms but in polarisable solvents (methanol, DMSO and water) TG5 is the most stabilized form. Variation of dipole moments and NBO charges on atoms in the solvents were studied.

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Potentiometric and 1H NMR study of the interaction of hypoxanthine and inosine with H+, Cu(II), and Zn(II)

Cited by 23 publications

References 21 publications

Density Functional Study of the Neutral Hypoxanthine Tautomeric Forms

Density Functional Study of the Neutral Hypoxanthine Tautomeric Forms

Tautomerism of Xanthine Oxidase Substrates Hypoxanthine and Allopurinol

Theoretical Survey on Tautomerism of Thioguanine Tautomers by Polarisable Continuum Method (PCM)

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