17O NMR spectroscopy of 4‐substituted pyridine N‐oxides: Substituent and solvent effects
17O NMR spectroscopy of 4‐substituted pyridine N‐oxides: Substituent and solvent effects
复制标题
4-取代吡啶氮氧化物的 17O NMR 谱：取代基和溶剂效应
DOI：
10.1002/mrc.1260230414
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发表时间：
1985
影响因子：
2
通讯作者：
P. Balakrishnan
中科院分区：
文献类型：
--
作者：
D. W. Boykin;A. Baumstark;P. Balakrishnan
The 17O chemical shifts for 4‐substituted pyridine N‐oxides at natural abundance were measured in acetonitrile at 50°C. Electron withdrawing groups caused deshielding and electron donating groups caused shielding of the 17O resonance. The data are correlated with 17O chemical shifts of substituted anisoles by DSP treatment and with ionization potentials. The chemical shift range for the substituents (methoxy to nitro) is exceptionally large (102 ppm). The 17O signal of the pyridine N‐oxides is substantially shifted in aqueous solution; the differences in chemical shifts between acetonitrile and water for the nitro, parent and methoxy compounds are 85, 75 and 59 ppm, respectively.
