Reaction of aromatic N-oxides with dipolarophiles. VII. Effect of aromaticity on 1,3-dipolar cycloaddition reactivity of substituted pyridine N-oxides and preparation of oxazolo[4,5-b]pyridine derivatives was written by Matsuoka, Toshikazu;Shinada, Minoru;Suematsu, Fumihiro;Harano, Kazunobu;Hisano, Takuzo. And the article was included in Chemical & Pharmaceutical Bulletin in 1984.Synthetic Route of C7H9NO This article mentions the following:
The 1,3-dipolar cycloaddition reactivity of pyridine N-oxides to Ph isocyanate was calculated by the MINDO/3 MO method using the perturbation equation derived by Klopman and Salem (1968). The calculation did not predict the low reactivity of acceptor substituted pyridine N-oxides. On the basis of the calculation data, the general 1,3-dipolar cycloaddition reactivity of pyridine N-oxides towards various Ph isocyanates is discussed in terms of the concept of cyclic conjugation. The aromaticity of the pyridine N-oxide may play an important role in determination of the reactivity. In connection with the cycloaddition, the 1,5-sigmatropic rearrangement of the primary cycloadducts and the pyrolytic reaction behavior of the 2,3-dihydropyridine derivatives formed by a 1,5-sigmatropic shift from the primary adducts are discussed on the basis of the MINDO/3 calculation data. In the experiment, the researchers used many compounds, for example, 3,5-Dimethylpyridine 1-oxide (cas: 3718-65-8Synthetic Route of C7H9NO).
3,5-Dimethylpyridine 1-oxide (cas: 3718-65-8) belongs to pyridine derivatives. Pyridine has a conjugated system of six 闂?electrons that are delocalized over the ring. The molecule is planar and, thus, follows the H闂佹椿浜滈妴鍗l criteria for aromatic systems. Several pyridine derivatives play important roles in biological systems. While its biosynthesis is not fully understood, nicotinic acid (vitamin B3) occurs in some bacteria, fungi, and mammals.Synthetic Route of C7H9NO