The structure of barbituric acid and its 5,5-diethyl derivative as revealed by 15N nuclear magnetic resonance techniques

Franken, Hans-Dieter; Rüterjans, Heinz; Müller, Franz

doi:10.1016/s0040-4020(01)88283-1

Cited by 8 publications

(2 citation statements)

References 33 publications

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“…The structures of possibly existing di‐, tri‐, and hexamers of 2,4,6‐pyrimidinetrione, resulting from intermolecular hydrogen bonds, have also been calculated 21. The ultraviolet (UV) 20, infrared (IR) 22, and 13 C 21, 23 and 15 N 24 nuclear magnetic resonance (NMR) spectra of 2,4,6‐pyrimidinetrione, as well as the electron spin resonance (ESR) spectrum of its radical 23 have been discussed on the basis of theoretical and experimental data 20–24.…”

Section: Introductionmentioning

confidence: 99%

Computational study of energies and structures of 2,4,6‐pyrimidinetrione and its anions

Daskalova

Binev

2005

Int J of Quantum Chemistry

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Energies and structures of 2,4,6-pyrimidinetrione, its anion, dianion, and trianion have been studied by means of ab initio and density functional computations. According to these studies, the most stable among the molecular tautomers is the triketo form, followed by the 6-hydroxy tautomer, in full agreement with earlier theoretical results and with experimental data on the tautomeric equilibrium. The deprotonation energy of 1345.24 kJ mol Ϫ1 calculated for 2,4,6-pyrimidinetrione, corresponds to a moderately strong COH acid, in accordance with its experimental pK a 1 ϭ 8.4 (solvent dimethylsulfoxide). The calculated structural changes, caused by the molecule 3 monoanion conversion, are in good agreement with those found experimentally. Energy and structural changes, worked by both anion 3 dianion and dianion 3 trianion conversions, have also been computed and discussed.

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Section: Introductionmentioning

confidence: 99%

Computational study of energies and structures of 2,4,6‐pyrimidinetrione and its anions

Daskalova

Binev

2005

Int J of Quantum Chemistry

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“…Barbituric acid can exist in a large number of tautomeric forms. The most stable tautomer of the compound is the triketo form [1][2][3]. The crystal structure analysis of anhydrous barbituric acid provides evidence for small amounts of some zwitterionic structures in the crystal [4].…”

Section: Introductionmentioning

confidence: 98%

Theoretical study of the excited-state reaction paths of the OH and NH dissociation processes in barbituric acid

Delchev

Ivanova

2012

Monatsh Chem

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We studied the OH and NH dissociation mechanisms of eight tautomers of barbituric acid via excited states. The theoretical research was performed at the TD DFT level of theory (B3LYP). It was found that all mechanisms pass through the repulsive 1 pr* excited state whose excited-state reaction paths showed conical intersections S 0 -S 1 . Some OH dissociation mechanisms showed barrierless 1 pr* reaction paths which indicate an ultrafast relaxation of the 1 pr* excited states to the ground state. The study of the NH dissociation mechanisms revealed that almost all 1 pr* reaction paths show low energy barriers and minima before the conical intersections S 0 -S 1 .

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1994

Chemistry of Heterocyclic Compounds: A Series of Monographs

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The structure of barbituric acid and its 5,5-diethyl derivative as revealed by 15N nuclear magnetic resonance techniques

Cited by 8 publications

References 33 publications

Computational study of energies and structures of 2,4,6‐pyrimidinetrione and its anions

Computational study of energies and structures of 2,4,6‐pyrimidinetrione and its anions

Theoretical study of the excited-state reaction paths of the OH and NH dissociation processes in barbituric acid

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