Reaction of aromatic N-oxides with dipolarophiles. Part 18. Formation mechanism and x-ray structure of the cycloadduct from sequential pericyclic reaction of pyridine N-oxides with phenylsulfonylallene was written by Matsuoka, Toshikazu;Hasegawa, Tomoaki;Eto, Masashi;Harano, Kazunobu;Hisano, Takuzo. And the article was included in Journal of the Chemical Society, Perkin Transactions 2: Physical Organic Chemistry (1972-1999) in 1993.Application In Synthesis of 3,5-Dimethylpyridine 1-oxide This article mentions the following:
Sequential pericyclic reactions of pyridine N-oxides (1) with phenylsulfonylpropadiene (2) and 1-phenylsulfonylpropyne (3) were investigated. 3,5-Dimethylpyridine N-oxide (1a) and 2 in CHCl3 at room temperature gave a mixture of the [1,5]-sigmatropic rearrangement product 4a of the 1:1 cycloadduct and the 1:2 azetidine-type cycloadduct 5a. The structure of 5a was determined crystallog. The reaction rate of 1a with 2 was ∼50,000 times that of 1a with N-phenylmaleimide. The reaction of 1a with 3 did not give 5a but 4a as the sole product. The reactivity, regio- and periselectivity, and formation mechanism of 4 and 5 are examined by FMO. In the experiment, the researchers used many compounds, for example, 3,5-Dimethylpyridine 1-oxide (cas: 3718-65-8Application In Synthesis of 3,5-Dimethylpyridine 1-oxide).
3,5-Dimethylpyridine 1-oxide (cas: 3718-65-8) belongs to pyridine derivatives. Pyridine has a dipole moment and a weaker resonant stabilization than benzene (resonance energy 117 kJ·mol−1 in pyridine vs. 150 kJ·mol−1 in benzene). Many analogues of pyridine are known where N is replaced by other heteroatoms . Substitution of one C–H in pyridine with a second N gives rise to the diazine heterocycles (C4H4N2), with the names pyridazine, pyrimidine, and pyrazine.Application In Synthesis of 3,5-Dimethylpyridine 1-oxide