Prototropic processes in benzaurins. 19F and 1H NMR spectra of fluoro- and methylsubstituted 4-hydroxyphenyl-diphenylcarbinols, related fuchsones and benzaurins

Poul Erik Hansen, Alexander S. Peregudov, Dmitii N. Kravtsov, Antonina I. Krylova, Galina M. Babakhina, Ludmila S. Golovchencko, Valentina M. Pachevskaya

Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review

Resumé

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.
OriginalsprogEngelsk
TidsskriftCentral European Journal of Chemistry
Vol/bind9
Udgave nummer2
Sider (fra-til)253-264
Antal sider12
ISSN1895-1066
DOI
StatusUdgivet - 2011

Emneord

  • benzaurins
  • tautomerism
  • 19F NMR
  • fuchsones

Citer dette

Hansen, Poul Erik ; Peregudov, Alexander S. ; Kravtsov, Dmitii N. ; Krylova, Antonina I. ; Babakhina, Galina M. ; Golovchencko, Ludmila S. ; Pachevskaya , Valentina M. / Prototropic processes in benzaurins. 19F and 1H NMR spectra of fluoro- and methylsubstituted 4-hydroxyphenyl-diphenylcarbinols, related fuchsones and benzaurins. I: Central European Journal of Chemistry. 2011 ; Bind 9, Nr. 2. s. 253-264.
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title = "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.",
keywords = "benzaurins, tautomerism, 19F NMR, fuchsones, 19F NMR , Prototropic tautomerism , Syn-anti isomerism , Fluoro- and methyl substituted benzaurins , Fuchsones",
author = "Hansen, {Poul Erik} and Peregudov, {Alexander S.} and Kravtsov, {Dmitii N.} and Krylova, {Antonina I.} and Babakhina, {Galina M.} and Golovchencko, {Ludmila S.} and Pachevskaya, {Valentina M.}",
year = "2011",
doi = "10.2478/s11532-011-0003-0",
language = "English",
volume = "9",
pages = "253--264",
journal = "Central European Journal of Chemistry",
issn = "1895-1066",
publisher = "Physica-Verlag",
number = "2",

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Prototropic processes in benzaurins. 19F and 1H NMR spectra of fluoro- and methylsubstituted 4-hydroxyphenyl-diphenylcarbinols, related fuchsones and benzaurins. / Hansen, Poul Erik; Peregudov, Alexander S. ; Kravtsov, Dmitii N.; Krylova, Antonina I.; Babakhina, Galina M.; Golovchencko, Ludmila S.; Pachevskaya , Valentina M.

I: Central European Journal of Chemistry, Bind 9, Nr. 2, 2011, s. 253-264.

Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review

TY - JOUR

T1 - Prototropic processes in benzaurins. 19F and 1H NMR spectra of fluoro- and methylsubstituted 4-hydroxyphenyl-diphenylcarbinols, related fuchsones and benzaurins

AU - Hansen, Poul Erik

AU - Peregudov, Alexander S.

AU - Kravtsov, Dmitii N.

AU - Krylova, Antonina I.

AU - Babakhina, Galina M.

AU - Golovchencko, Ludmila S.

AU - Pachevskaya , Valentina M.

PY - 2011

Y1 - 2011

N2 - 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.

AB - 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.

KW - benzaurins

KW - tautomerism

KW - 19F NMR

KW - fuchsones

KW - 19F NMR

KW - Prototropic tautomerism

KW - Syn-anti isomerism

KW - Fluoro- and methyl substituted benzaurins

KW - Fuchsones

U2 - 10.2478/s11532-011-0003-0

DO - 10.2478/s11532-011-0003-0

M3 - Journal article

VL - 9

SP - 253

EP - 264

JO - Central European Journal of Chemistry

JF - Central European Journal of Chemistry

SN - 1895-1066

IS - 2

ER -