Infrared spectra of heterocyclic compounds. V. Infrared spectra of substituted pyridine 1-oxides was written by Shindo, Hideyo. And the article was included in Chemical & Pharmaceutical Bulletin in 1958.Synthetic Route of C7H9NO This article mentions the following:
The following derivatives of pyridine 1-oxide (I) were prepared by previously described methods (Ochiai, C.A. 48, 3359i)(substituent and m.p. given): 4-O2N, 160°; 4-Cl, 169.5° (decomposition); 4-Br, 146° (decomposition); 4-MeO, 83°; 4-PhCH2O, 176°; 3-O2N, 172°; 3-NC, 178°; 3-Ac, 147°; 3-Br, about 40°; 3-Cl, 60°. The infrared spectra of these compounds were measured in CS2 solution or in Nujol and the results tabulated, together with those of the 4-NC, 4-NaO3S, 2-Me, 3-Me, 3-Et, 4-Me, 4-Et, 3,5-Me2, 3,4-Me(O2N), 3,4-Me(H2N), 2,4-Me(O2N), 2,6,4-Me2(O2N), 4-Ac, 4-EtO2C, 3-EtO2C, 3-H2NCO, 4-H2NCO, 3-H2N, 4-H2N, and 2-H2N derivatives of I, and 4,4′-, 3,3′-, and 2,2′-bipyridine N,N’-dioxides. The results were discussed in terms of an electronic effect of the N-oxide group with relation to (1) its stretching frequencies (strong absorption in the region 1200-1300 cm.-1) as affected by the electronic effect of the substituent, whereby a linear relation was found between these frequencies and the σ-value of the substituent, (2) the ring CH out-of-plane bending frequencies, which were shifted from those of the parent pyridines to a higher frequency for 2- and 4-substituted derivatives and to a lower for 3-substituted, (3) the ring CH in-plane bending mode and the ring double-bond stretching vibrations at 900-1200 and 1450-1630 cm.-1, resp., both correlated with the positions of the substituents, and (4) the effect of the N-oxide group in shifting the absorption frequencies of the substituents, whereby the σ-values 0.25 and 1.18 were obtained for the 4- and 3-positions, resp., of I. 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. In contrast to benzene, Pyridine’s electron density is not evenly distributed over the ring, reflecting the negative inductive effect of the nitrogen atom. Pyridine groups exist in countless molecules, and their applications include catalysis, drug design, molecular recognition, and natural product synthesis.Synthetic Route of C7H9NO