17O NMR studies of electronic and steric interactions of substituted quinoxaline-2(1H),3(4H)-diones
β Scribed by Ioannis P. Gerothanassis; George Varvounis
- Book ID
- 112131518
- Publisher
- Journal of Heterocyclic Chemistry
- Year
- 1996
- Tongue
- English
- Weight
- 316 KB
- Volume
- 33
- Category
- Article
- ISSN
- 0022-152X
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π SIMILAR VOLUMES
## Abstract ^17^O NMR was used to probe the steric and electronic substituent effects in furanβ2,3βdione derivatives. The carbonyl ^17^O chemical shifts correlate with Hammett constants and IR carbonyl stretching band frequencies for 5β(__para__βsubstitutedβphenyl)furanβ2,3βdiones.
## Abstract ^1^H, ^13^C and ^17^O NMR spectra for 22 substituted nitropyridines were measured and their ^1^H NMR spectra were analysed. The most significant variations in the NMR parameters are found for isomeric hydroxy derivatives, owing to the possibility of ketoβenol tautomerism. The prevalence