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

Abstract

The complete 1H 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 1H 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 13C NMR spectra of 1–3 and 1a–3a and the effect of N(10)‐oxidation on the 13C 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.

Hydroacridines: part 29.15N NMR chemical shifts of 9‐substituted 1,2,3,4,5,6,7,8‐octahydroacridines and theirN‐oxides—Taft, Swain–Lupton, and other types of linear correlations

“…However, in a previous paper of this series [25] we showed that, due to steric hindrance, in 9a, 9b, 10a, and 10b there is a torsion angle of about 90…”

“…Octahydroacridines 1a-13a and the corresponding N-oxides 1b-13b examined in this paper. octahydroacridine (6a), [1] 9-acetylamino-1,2,3,4,5,6,7,8-octahydroacridine (7a), [1] 1,2,3,4,5,6,7,8-octahydro-9-nitroacridine (8a), [28] 1,2,3,4,5,6,7,8-octahydro-9-(3-pyridyl)-acridine (9a), [29] 1,2,3,4,5,6,7,8-octahydro-9-(4-pyridyl)-acridine (10a), [29] and 1,2, 3,4,5,6,7,8-octahydro-9-(2-furyl)-acridine (11a), [30] 9-diacetylamino-1,2,3,4,5,6,7,8-octahydroacridine (12a), [1] 1,2,3,4,5,6,7,8-octahydro-9-hydroxyacridine (13a), [1] and the corresponding 10-oxides (N-oxides) 1b, [31] 2b, 3b, [1] 4b, [1] 5b, [1] 6b, [1] 7b, [1] 8b, [32] 9b, [25] 10b, [25] 11b, 12b, [1] and 13b, [1] respectively (Scheme 1). The measured 15 N chemical shifts of 1a-13a and 1b-13b, compared with the values calculated by various correlation methods, are listed in Tables 1 and 2, respectively.…”

“…The solvation model was SM5.1 P [40 -43] and the atomic charge densities represent the Charge Model 1 (CM1) charges used in the solvent-dependent calculations. Ethyl-1,2,3,4,5,6,7,8-octahydroacridine-10-oxide (2b) To a solution of 1.57 g (7.3 mM) of 2a [27] in 15 ml of CHCl 3 , a solution of 2.1 g (10.95 mM) of about 93% pure 3-chloroperoxybenzoic acid [25] in 15 ml of CHCl 3 was added in small portions, under cooling (tape water) and shaking by hand. The reaction mixture was then left to stand in an open beaker, at room temperature, until the solvent completely evaporated.…”

“…However, to the best of our knowledge, so far, neither Hammett-type correlations for the 15 In the last two decades, sym-octahydroacridine and its substituted derivatives gained much in interest as starting materials in the syntheses of hydrogen-bonding receptors for biomolecules, [13 -18] of metal-bonding polyaza torands, [18 -20] and of other polyaza cavity-shaped ligands. [18,20 -24] In a previous work of this series [25] we have studied the structures of several symoctahydroacridines and of their N-oxides by 1 H and 13 C NMR spectroscopy. In the present paper we report on the 15 N NMR chemical shifts of sym-octahydroacridine, of 12 of its 9-substituted derivatives, and of the corresponding N-oxides.…”

Hydroacridines: Part 30. 1H and 13C NMR spectra of 9‐substituted 1,2,3,4,5,6,7,8‐octahydroacridines and of their N‐oxides

“…The compounds under consideration were 1,2,3,4,5,6,7,8-octahydroacridine (1a) [14] and -10-oxide (1b), [14] 9-ethyl-1,2,3,4,5,6,7,8-octahydroacridine (2a) [15] and -10-oxide (2b), [1] 9-chloro-1,2,3,4,5,6,7,8-octahydroacridine (3a), [16] and -10-oxide (3b), [16] 9-bromo-1,2,3,4,5,6,7,8-octahydroacridine (4a) [16] and -10-oxide, [16] 1,2,3,4,5,6,7,8-octahydro-9-methoxyacridine (5a) [16] and -10-oxide (5b), [16] 9-amino-1,2,3,4,5,6,7,8-octahydroacridine (6a) [16] and -10-oxide (6b), [16] 9-acetylamino-1,2,3,4,5,6,7,8-octahydroacridine (7a) [16] and -10-oxide (7b), [16] 9-diacetylamino-1,2,3,4,5,6,7,8-octahydroacridine (8a) [16] and -10-oxide (8b), [16] 1,2,3,4,5,6,7,8-octahydro-9-nitroacridine (9a) [17] and -10-oxide (9b), [18] 9-(2-furyl)-1,2,3,4,5,6,7,8-octahydroacridine (10a) [19] and -10-oxide (10b), [1] 1,2,3,4,5,6,7,8-octahydro-9-(3-pyridyl)-acridine (11a) [14] and -10-oxide (11b), [14] 1,2,3,4,5,6,7,8-octahydro-9-(4-pyridyl)-acridine (12a) [14] and -10-oxide (12b), [14] and 1,2,3,4,5,6,7,8-octahydro-9-hydroxyacridine (13a) [16] and -10-oxide (13b) [16] (Scheme 1). For 1,2,3,4,5,6,7,8-octahydroacridine-9-carboxylic acid ethyl ester (14a), 1 H NMR chemical shifts with two erroneously reversed assignments and 13 C chemical shifts with no assignment have been reported in the literature.…”