Ring-chain tautomerism with participation of pyridine nitrogen: The intramolecular cyclization of 2-pyridinecarboxaldehyde-indandione adducts in acidic medium

Mark V. Sigalov

doi:10.1016/j.molstruc.2014.06.021

Ring-chain tautomerism with participation of pyridine nitrogen: The intramolecular cyclization of 2-pyridinecarboxaldehyde-indandione adducts in acidic medium

Mark V. Sigalov

Department of Chemistry

Research output: Contribution to journal › Article › peer-review

5 Scopus citations

Abstract

Keto-enol tautomerism of 2-pyridine carboxaldehyde adducts with ring-substituted 1,3-indandione derivatives observed in neutral solutions, in the presence of trifluoroacetic acid (TFA) is changed by the previously unknown prototropic ring-chain tautomerism with reversible quaternization of pyridine nitrogen. The proposed mechanism of tautomerization includes intramolecular proton transfer from the protonated nitrogen to indandione carbonyl oxygen, with subsequent cyclization of the unstable O-protonated intermediate. Neutralization of TFA leads to recovery of the keto-enol tautomers.

Original language	English
Pages (from-to)	302-309
Number of pages	8
Journal	Journal of Molecular Structure
Volume	1074
DOIs	https://doi.org/10.1016/j.molstruc.2014.06.021
State	Published - 25 Sep 2014

Keywords

DFT and MP2 calculations
Keto-enol and ring-chain tautomerism
NMR spectroscopy
Pyridine carboxaldehyde-indandione adducts
Tautomerization mechanism

ASJC Scopus subject areas

Analytical Chemistry
Spectroscopy
Organic Chemistry
Inorganic Chemistry

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10.1016/j.molstruc.2014.06.021

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title = "Ring-chain tautomerism with participation of pyridine nitrogen: The intramolecular cyclization of 2-pyridinecarboxaldehyde-indandione adducts in acidic medium",

abstract = "Keto-enol tautomerism of 2-pyridine carboxaldehyde adducts with ring-substituted 1,3-indandione derivatives observed in neutral solutions, in the presence of trifluoroacetic acid (TFA) is changed by the previously unknown prototropic ring-chain tautomerism with reversible quaternization of pyridine nitrogen. The proposed mechanism of tautomerization includes intramolecular proton transfer from the protonated nitrogen to indandione carbonyl oxygen, with subsequent cyclization of the unstable O-protonated intermediate. Neutralization of TFA leads to recovery of the keto-enol tautomers.",

keywords = "DFT and MP2 calculations, Keto-enol and ring-chain tautomerism, NMR spectroscopy, Pyridine carboxaldehyde-indandione adducts, Tautomerization mechanism",

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doi = "10.1016/j.molstruc.2014.06.021",

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T1 - Ring-chain tautomerism with participation of pyridine nitrogen

T2 - The intramolecular cyclization of 2-pyridinecarboxaldehyde-indandione adducts in acidic medium

AU - Sigalov, Mark V.

PY - 2014/9/25

Y1 - 2014/9/25

N2 - Keto-enol tautomerism of 2-pyridine carboxaldehyde adducts with ring-substituted 1,3-indandione derivatives observed in neutral solutions, in the presence of trifluoroacetic acid (TFA) is changed by the previously unknown prototropic ring-chain tautomerism with reversible quaternization of pyridine nitrogen. The proposed mechanism of tautomerization includes intramolecular proton transfer from the protonated nitrogen to indandione carbonyl oxygen, with subsequent cyclization of the unstable O-protonated intermediate. Neutralization of TFA leads to recovery of the keto-enol tautomers.

AB - Keto-enol tautomerism of 2-pyridine carboxaldehyde adducts with ring-substituted 1,3-indandione derivatives observed in neutral solutions, in the presence of trifluoroacetic acid (TFA) is changed by the previously unknown prototropic ring-chain tautomerism with reversible quaternization of pyridine nitrogen. The proposed mechanism of tautomerization includes intramolecular proton transfer from the protonated nitrogen to indandione carbonyl oxygen, with subsequent cyclization of the unstable O-protonated intermediate. Neutralization of TFA leads to recovery of the keto-enol tautomers.

KW - DFT and MP2 calculations

KW - Keto-enol and ring-chain tautomerism

KW - NMR spectroscopy

KW - Pyridine carboxaldehyde-indandione adducts

KW - Tautomerization mechanism

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U2 - 10.1016/j.molstruc.2014.06.021

DO - 10.1016/j.molstruc.2014.06.021

M3 - Article

AN - SCOPUS:84903693685

SN - 0022-2860

VL - 1074

SP - 302

EP - 309

JO - Journal of Molecular Structure

JF - Journal of Molecular Structure

ER -

Ring-chain tautomerism with participation of pyridine nitrogen: The intramolecular cyclization of 2-pyridinecarboxaldehyde-indandione adducts in acidic medium

Abstract

Keywords

ASJC Scopus subject areas

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