In organic chemistry, atoms other than carbon and hydrogen are generally referred to as heteroatoms. The most common heteroatoms are nitrogen, oxygen and sulfur. Now I present to you an article called The influence of steric effect on 1H NMR, 13C NMR, and IR spectra of methylated derivatives of 4-nitropyridine N-oxide, published in 1995, which mentions a compound: 14248-66-9, mainly applied to carbon NMR steric effect methylnitropyridine oxide; hydrogen NMR steric effect methylnitropyridine oxide; proton NMR steric effect methylnitropyridine oxide; IR steric effect methylated nitropyridine oxide, SDS of cas: 14248-66-9.
The 1H NMR, 13C NMR, and IR spectra of 2-methyl-. 2,3-dimethyl-, 2,5-dimethyl-, 2,6-dimethyl-, 3,5-dimethyl-, and 2,3,6-trimethyl-4-nitropyridine N-oxides were interpreted. The influence of electron properties of substituents on changes of chem. shifts was analyzed. It was found that “”ortho-effect”” of the Me group inhibits paramagnetism of the nitro group. The ratio between a given substituted heterocyclic compound, its parent compound and the identically substituted benzene derivatives has been determined It was found that the effect of the nitro group on chem. shift and the so-called back donation is modified by electronegativity and the position of the substituent.
Here is just a brief introduction to this compound(14248-66-9)SDS of cas: 14248-66-9, more information about the compound(3,5-Dimethyl-4-nitropyridine 1-oxide) is in the article, you can click the link below.
Reference:
Isoxazole – Wikipedia,
Isoxazole | C3H3NO – PubChem