Deuterium isotope effects on aromatic carbon-13 chemical shifts. V. Nonadditivity of methyl substituent effects on one-bond isotope shifts for methylpyridine N-oxides was written by Nakashima, Yasuki;Fukunaga, Moritaka;Suzuki, Keiko;Takahashi, Kensuke. And the article was included in Bulletin of the Chemical Society of Japan in 1993.Formula: C7H9NO This article mentions the following:
One- and two-bond deuterium isotope effects (1Δ and 2Δ) on 13C chem. shifts for methylpyridines and their N-oxides were investigated. The 1Δ values for methylpyridines agree with the calculated values, which are based on a simple additive rule of the Me substituent effects. The additive rule was not satisfied for 1Δ of the N-oxides. This is attributed to a steric interaction between the substituent and the N-oxide group. In the experiment, the researchers used many compounds, for example, 3,5-Dimethylpyridine 1-oxide (cas: 3718-65-8Formula: C7H9NO).
3,5-Dimethylpyridine 1-oxide (cas: 3718-65-8) belongs to pyridine derivatives. In contrast to benzene, Pyridine’s electron density is not evenly distributed over the ring, reflecting the negative inductive effect of the nitrogen atom. One of the examples of pyridines is the well-known alkaloid lithoprimidine, which is an A3 adenosine receptor antagonist and N,N-dimethylaminopyridine (DMAP) analog, commonly used in organic synthesis.Formula: C7H9NO