Journal ArticleDOI
Nitrogen-14 nuclear quadrupole resonance study of several hydroxypyrimidines
S. N. Subbarao,P. J. Bray +1 more
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TLDR
In this paper, the semi-empirical Townes and Dailey theory was applied to the NQR spectra of several hydroxypyrimidines of biological and pharmacological importance.Abstract:
Nitrogen‐14 nuclear quadrupole resonance (NQR) spectra of several hydroxypyrimidines of biological and pharmacological importance are reported and analyzed in the framework of the semiempirical Townes and Dailey theory. Included among the compounds are thymine, uracil, uridine, barbituric acid, orotic acid, and cyanuric acid. The results obtained suggest that in all cases the molecules in their ground state exist predominantly in the dilactam tautomeric form. Significant differences have been observed in the NQR spectra of the two nitrogens in barbituric acid which cannot be accounted for by the differences in the hydrogen bond lengths alone.read more
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Book ChapterDOI
Recent Progress in Barbituric Acid Chemistry
TL;DR: In this article, the chemistry and pharmacology and physicochemical properties of barbiturates, along with the tautomerism and solvation of the Barbituric acid ring are discussed.
Journal ArticleDOI
Analysis of 13C, 14N residual dipolar coupling in the 13C CP/MAS NMR spectra of ribonucleosides
TL;DR: In this article, solid-state 13C NMR spectra at 25 MHz of ribonucleosides are analyzed on the basis of the isotropic chemical shifts measured at 50 MHz, together with the asymmetric splittings caused by the presence of 14N calculated using a first-order equation.
Journal ArticleDOI
Studies on some thiazolylazo compounds and their cobalt, nickel, and copper complexes
TL;DR: In this paper, the thiazolylazo compounds and their Co(II), Ni(II) and Cu(II)-clusters of barbituric acid, uracil, thiouracil and citrazinic acid were prepared and characterized by 1H NMR, IR and the effect of pH on the electronic absorption spectra.
Journal ArticleDOI
Tautomerism and Possible Polymorphism in Solid Hydroxypyridines and Pyridones Studied by 14N NQR
TL;DR: In 3-hydroxypyridine, molecular librations dominate the temperature variation of the quadrupole coupling constant, whereas in 2- and 4-pyridone, the changes in the hydrogen bonding interactions with temperature seem to give the dominant effect.
Journal ArticleDOI
Effect of amino substitution on the excited state dynamics of uracil.
TL;DR: The excited state deactivation of two amino-substituted uracils in aqueous solution was studied by femtosecond fluorescence upconversion and indicates the formation of a transient fluorescent state which in turn is deactivated by a different relaxation process specific to the amino group.
References
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Journal ArticleDOI
Determination of Electronic Structure of Molecules from Nuclear Quadrupole Effects
TL;DR: In this article, it was shown that this variation of electric field is usually simply related to the molecular electronic structure, being primarily dependent on the way in which valence electrons fill the lowest energy p-type orbits.
Journal ArticleDOI
Nuclear Quadrupole Resonance Spectroscopy
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