Ab initio and 17O NMR studies of the substituent effects on the tautomeric equilibrium in 6-X-1H-2-pyridones

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17O chemical shifts are found to be highly sensitive probes in the study of keto-enol tautomeric equilibria due to the strong sensitivity of these shifts to the coordination of the oxygen atom. The large shielding effect observed, both experimentally and theoretically, for the carbonyl oxygen atom i...

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Autores principales: Facelli, J.C., Orendt, A.M., Contreras, R.H., Tufró, M.F., De Kowalewski, D.G.
Formato: Artículo publishedVersion
Lenguaje:Inglés
Publicado: 1992
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_00223654_v96_n20_p7895_Facelli
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Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
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spelling paperaa:paper_00223654_v96_n20_p7895_Facelli2023-06-12T16:44:46Z Ab initio and 17O NMR studies of the substituent effects on the tautomeric equilibrium in 6-X-1H-2-pyridones Journal of Physical Chemistry 1992;96(20):7895-7898 Facelli, J.C. Orendt, A.M. Contreras, R.H. Tufró, M.F. De Kowalewski, D.G. 17O chemical shifts are found to be highly sensitive probes in the study of keto-enol tautomeric equilibria due to the strong sensitivity of these shifts to the coordination of the oxygen atom. The large shielding effect observed, both experimentally and theoretically, for the carbonyl oxygen atom in 2-pyridone suggests that the carbonyl π-electronic system is undergoing a strong conjugation with the formal C3=C4 double bond and/or the nitrogen lone pair. A Cl or NH2 substitution at position 6 of the pyridine ring shifts the tautomeric equilibrium toward the 2-hydroxypyridine form, while a CH3 substitution results in the keto form being predominant, as is the case in the parent compound. © 1992 American Chemical Society. Fil:Facelli, J.C. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Contreras, R.H. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Tufró, M.F. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. 1992 info:eu-repo/semantics/article info:ar-repo/semantics/artículo info:eu-repo/semantics/publishedVersion application/pdf eng info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_00223654_v96_n20_p7895_Facelli
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
language Inglés
orig_language_str_mv eng
description 17O chemical shifts are found to be highly sensitive probes in the study of keto-enol tautomeric equilibria due to the strong sensitivity of these shifts to the coordination of the oxygen atom. The large shielding effect observed, both experimentally and theoretically, for the carbonyl oxygen atom in 2-pyridone suggests that the carbonyl π-electronic system is undergoing a strong conjugation with the formal C3=C4 double bond and/or the nitrogen lone pair. A Cl or NH2 substitution at position 6 of the pyridine ring shifts the tautomeric equilibrium toward the 2-hydroxypyridine form, while a CH3 substitution results in the keto form being predominant, as is the case in the parent compound. © 1992 American Chemical Society.
format Artículo
Artículo
publishedVersion
author Facelli, J.C.
Orendt, A.M.
Contreras, R.H.
Tufró, M.F.
De Kowalewski, D.G.
spellingShingle Facelli, J.C.
Orendt, A.M.
Contreras, R.H.
Tufró, M.F.
De Kowalewski, D.G.
Ab initio and 17O NMR studies of the substituent effects on the tautomeric equilibrium in 6-X-1H-2-pyridones
author_facet Facelli, J.C.
Orendt, A.M.
Contreras, R.H.
Tufró, M.F.
De Kowalewski, D.G.
author_sort Facelli, J.C.
title Ab initio and 17O NMR studies of the substituent effects on the tautomeric equilibrium in 6-X-1H-2-pyridones
title_short Ab initio and 17O NMR studies of the substituent effects on the tautomeric equilibrium in 6-X-1H-2-pyridones
title_full Ab initio and 17O NMR studies of the substituent effects on the tautomeric equilibrium in 6-X-1H-2-pyridones
title_fullStr Ab initio and 17O NMR studies of the substituent effects on the tautomeric equilibrium in 6-X-1H-2-pyridones
title_full_unstemmed Ab initio and 17O NMR studies of the substituent effects on the tautomeric equilibrium in 6-X-1H-2-pyridones
title_sort ab initio and 17o nmr studies of the substituent effects on the tautomeric equilibrium in 6-x-1h-2-pyridones
publishDate 1992
url http://hdl.handle.net/20.500.12110/paper_00223654_v96_n20_p7895_Facelli
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