A MULTINUCLEAR1H, 13C, and 15N MAGNETIC RESONANCE STUDY OF TEN 4-NITROPYRIDINE N-OXIDES
A. Puszko1, K. Laihia2, E. Kolehmainen2, Z. Talik1
1University of Economics, Wrocław, Poland
apuszko@gmail.com
2University of Jyväskylä, Finland
Ключевые слова: 1H, 13C, 15N NMR, 4-nitropyridine N-oxide
Страницы: 1216-1220
Аннотация
The 1H, 13C, and 15N NMR chemical shifts of ten 4-nitropyridine N-oxide derivatives are assigned. The shielding of the pyridine ring nitrogen is sensitive to ring substitution through inductive effects, steric effects by ortho-substituents, and the possibility for electron delocalisation (resonance energy). In solution, 3-ethylnitrosoamino-4-nitropyridine N-oxide has two tautomers. The proposed reason is the steric crowding between vicinal 4-nitro and 3-ethylnitrosoamino groups, causing a disturbance to amino nitrogen that can delocalize its lone pair to the oxygen atom of the nitroso group.
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