## Abstract ^1^H, ^13^C and ^17^O NMR spectra for 22 substituted nitropyridines were measured and their ^1^H NMR spectra were analysed. The most significant variations in the NMR parameters are found for isomeric hydroxy derivatives, owing to the possibility of keto–enol tautomerism. The prevalence
1H, 13C and 17O NMR spectral study of 4,1-disubstituted naphthalenes
✍ Scribed by Subbu Perumal; Gnanasambandam Vasuki; David A. Wilson; David W. Boykin
- Publisher
- John Wiley and Sons
- Year
- 1992
- Tongue
- English
- Weight
- 565 KB
- Volume
- 30
- Category
- Article
- ISSN
- 0749-1581
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✦ Synopsis
Abstract
The ^1^H, ^13^C and ^17^O NMR spectra of several 4,1‐disubstituted naphthalenes, viz. 4‐substituted 1‐ acetylnaphthalenes (series 1), 4‐substituted 1‐nitronaphthalenes (series 2), 4‐substituted 1‐methoxynaphthalenes (series 3) and 4‐substituted 1‐naphthyl methyl sulphides (series 4), were measured. The ^17^O and ^13^C chemical shifts of these 4,1‐disubstituted naphthalenes were compared with those of the corresponding 4,1‐disubstituted benzenes and analysed using the dual substituted parameter (DSP) equation. It is concluded that in series 1, 2 and 4 the substituent effects from the 4‐substituent to the C‐1 carbon and the side‐chain atoms are transmitted more effectively than those in the corresponding 4,1‐disubstituted benzenes, whereas the transmission in series 3 is almost equal to that in the analogous benzene series, viz. 4‐substituted anisoles. The reverse substituent effects displayed by the H‐8 chemical shifts of series 1 and 2 and the existence of linear relationships between the chemical shifts of H‐8 and the ^17^O chemical shifts of the oxygen of both the acetyl and nitro groups in series 1 and 2, respectively, are ascribed mainly to changes in the electron densities on the oxygen of the carbonyl and nitro groups affecting the diamagnetic screening of the proton.
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