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RESEARCH PRODUCT
1H,13C and17O NMR study of substituted nitropyridines
Erkki KolehmainenRyszard GawineckiDanuta RasałaKatri Laihiasubject
ChemistryStereochemistryGeneral ChemistryKeto–enol tautomerismNuclear magnetic resonance spectroscopyDihedral angleTautomerEnolchemistry.chemical_compoundMolecular dynamicsComputational chemistryNitroProton NMRGeneral Materials Sciencedescription
1H, 13C and 17O NMR spectra for 22 substituted nitropyridines were measured and their 1H NMR spectra were analysed. The most significant variations in the NMR parameters are found for isomeric hydroxy derivatives, owing to the possibility of keto–enol tautomerism. The prevalence of the keto form is observed in 2- and 4-hydroxy derivatives, while the 3-hydroxy derivative exists in its enol form. Among the three nuclei studied, 17O seems to be the best nucleus for probing the keto–enol tautomerism. No correlation is observed between the torsion angle of the nitro group and its 17O NMR chemical shift. Molecular mechanics calculations were performed to clarify the torsional energetics of the nitro group and the preferences for keto–enol tautomerism.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 1991-09-01 | Magnetic Resonance in Chemistry |