Hydroacridines: Part 23.1H and 13C NMR spectra of sym-octahydroacridine, its 9-(3-pyridyl) and 9-(4-pyridyl) derivatives and the corresponding N(10)-oxides. An experimental approach to the diamagnetic anisotropy of the pyridine nucleus
✍ Scribed by Francisc Potmischil; Călin Deleanu; Maria Marinescu; Mircea D. Gheorghiu
- Publisher
- John Wiley and Sons
- Year
- 2002
- Tongue
- English
- Weight
- 106 KB
- Volume
- 40
- Category
- Article
- ISSN
- 0749-1581
- DOI
- 10.1002/mrc.996
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✦ Synopsis
Abstract
The complete ^1^H NMR chemical shift assignments of 1,2,3,4,5,6,7,8‐octahydroacridine (1), 1,2,3,4,5,6,7,8‐octahydro‐9‐(3‐pyridyl)acridine (2), 1,2,3,4,5,6,7,8‐octahydro‐9‐(4‐pyridyl)acridine (3) and the corresponding N(10)‐oxides 1a, 2a and 3a, respectively, were achieved on the basis of 400 MHz ^1^H NMR spectra and proton–proton decoupling, HMQC and NOEDIFF experiments. The spectral data for the above compounds provided the first experimental evidence of the difference in the anisotropy effect of the two non‐symmetrical moieties of the pyridine nucleus, and allowed us to ascertain that the shielding effect of the moiety defined by the C(2′)—N—C(6′) atoms is weaker than that of the C(3′)—C(4′)—C(5′) moiety. The ^13^C NMR spectra of 1–3 and 1a–3a and the effect of N(10)‐oxidation on the ^13^C NMR chemical shifts are also discussed. The N‐oxidation of 2 and 3 with m‐chloroperbenzoic acid occurred regiospecifically, affording the N(10)‐oxides 2a and 3a free of N(1′)‐oxide isomers. Copyright © 2002 John Wiley & Sons, Ltd.