Prototropic processes in benzaurins. 19F and 1H NMR spectra of fluoro- and methylsubstituted 4-hydroxyphenyl-diphenylcarbinols, related fuchsones and benzaurins
Abstract: Tautomerism of benzaurins and hydration are studied. 1H and 19F chemical shifts have been determined for a number of substituted 4-hydroxyphenyl-diphenyl carbinols containing fluorine in a 3-, 3*- or 4*-position, and for similar compounds containing additional methyl groups in a position of 3, 3** or 4**. The same data have been obtained for the fuchsones prepared by dehydration of the above carbinols. On this basis chemical shifts of fluorine in different positions have been evaluated as a monitor of the transformation of 4-hydroxyphenyl group to the semiquinone moiety. The 19F NMR can be used to monitor the transformation of 4**-fluorobenzaurin and the related 3,3*-disubstituted and 3,3*,5,5*-tetramethylsubstituted compounds to the corresponding carbinols due to the addition of a water molecule and to study the tautomerism of the two latter benzaurins as well as that of 3,3*,4**trifluorobenzaurin. Furthermore, fluorine and methyl group chemical shifts are sensitive to syn-anti-isomerism in substituted fuchsones. The prototropic process of these compounds may be slow or fast on a 1H NMR time scale depending on the solvent and may be catalyzed by water or carbonic acids. On the basis of kinetic and thermodynamic data obtained by dynamic NMR studies, a mechanism for the process has been proposed.
- Location
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Deutsche Nationalbibliothek Frankfurt am Main
- Extent
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Online-Ressource
- Language
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Englisch
- Bibliographic citation
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Prototropic processes in benzaurins. 19F and 1H NMR spectra of fluoro- and methylsubstituted 4-hydroxyphenyl-diphenylcarbinols, related fuchsones and benzaurins ; volume:9 ; number:2 ; year:2011 ; pages:253-264 ; extent:12
Open chemistry ; 9, Heft 2 (2011), 253-264 (gesamt 12)
- Creator
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Hansen, Poul
Peregudov, Alexsander
Kravtsov, Dimitrii
Krylova, Antonina
Babakhina, Galina
Golovchenko, Ludmila
Pachevskaya, Valentina
- DOI
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10.2478/s11532-011-0003-0
- URN
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urn:nbn:de:101:1-2410181654361.087708071640
- Rights
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Open Access; Der Zugriff auf das Objekt ist unbeschränkt möglich.
- Last update
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15.08.2025, 7:24 AM CEST
Data provider
Deutsche Nationalbibliothek. If you have any questions about the object, please contact the data provider.
Associated
- Hansen, Poul
- Peregudov, Alexsander
- Kravtsov, Dimitrii
- Krylova, Antonina
- Babakhina, Galina
- Golovchenko, Ludmila
- Pachevskaya, Valentina