Conformation analyses, dynamic behavior, and amide bond distortions of medium-sized heterocycles. 2. Partially and fully reduced 1-benzazocines, benzazonines, and benzazecines
Conformation analyses, dynamic behavior, and amide bond distortions of medium-sized heterocycles. 2. Partially and fully reduced 1-benzazocines, benzazonines, and benzazecines
Partially and fully reduced forms of benzo-fused eight- to ten-membered nitrogen heterocycles (1-benzazecines, 1-benzazonines and 1-benzazecines) have been prepared. Conformational features, transannular distances and dynamic behavior were studied using X-ray crystallography and VT NMR spectroscopy. The amide moiety in the nine-membered benzazonine ring 5b favors N-pyramidization, whereas the ten-membered benzazecine 5c adopts an amide twist. Molecular mechanics calculations reveals a correlation between the amide twist (T) and ring stability. The dynamic behavior of the heterocycles in solution were also found to be dependent on the extent and nature of the amide distortion. We thus conclude that ring strain of these medium-sized heterocyclic rings is relieved through amide distortion, which leads to a more stable structure.
1552-1557
Qadir, Maryiam
1369ef6b-903b-4b48-bf39-3d218c10730d
Cobb, Jonathan
9d0d47a7-53ee-4d87-aeb1-e152dc3711ca
Sheldrake, Peter W.
892cd866-3523-4760-83e9-2015c7b20321
Whittall, Neil
8a7265c5-e0e6-4c1f-98ad-25d763461a0e
White, Andrew J.P.
09c64321-ac83-40be-a22c-3d62e4b19a7e
Hii, King Kuok (Mimi)
6c1f6010-03c3-44e2-9c32-f085bcfd935a
Horton, Peter N.
48f162d1-d6ce-43c1-aeef-d58b3ec702b8
Hursthouse, Michael B.
57a2ddf9-b1b3-4f38-bfe9-ef2f526388da
4 March 2005
Qadir, Maryiam
1369ef6b-903b-4b48-bf39-3d218c10730d
Cobb, Jonathan
9d0d47a7-53ee-4d87-aeb1-e152dc3711ca
Sheldrake, Peter W.
892cd866-3523-4760-83e9-2015c7b20321
Whittall, Neil
8a7265c5-e0e6-4c1f-98ad-25d763461a0e
White, Andrew J.P.
09c64321-ac83-40be-a22c-3d62e4b19a7e
Hii, King Kuok (Mimi)
6c1f6010-03c3-44e2-9c32-f085bcfd935a
Horton, Peter N.
48f162d1-d6ce-43c1-aeef-d58b3ec702b8
Hursthouse, Michael B.
57a2ddf9-b1b3-4f38-bfe9-ef2f526388da
Qadir, Maryiam, Cobb, Jonathan, Sheldrake, Peter W., Whittall, Neil, White, Andrew J.P., Hii, King Kuok (Mimi), Horton, Peter N. and Hursthouse, Michael B.
(2005)
Conformation analyses, dynamic behavior, and amide bond distortions of medium-sized heterocycles. 2. Partially and fully reduced 1-benzazocines, benzazonines, and benzazecines.
Journal of Organic Chemistry, 70 (5), .
(doi:10.1021/jo048117j).
Abstract
Partially and fully reduced forms of benzo-fused eight- to ten-membered nitrogen heterocycles (1-benzazecines, 1-benzazonines and 1-benzazecines) have been prepared. Conformational features, transannular distances and dynamic behavior were studied using X-ray crystallography and VT NMR spectroscopy. The amide moiety in the nine-membered benzazonine ring 5b favors N-pyramidization, whereas the ten-membered benzazecine 5c adopts an amide twist. Molecular mechanics calculations reveals a correlation between the amide twist (T) and ring stability. The dynamic behavior of the heterocycles in solution were also found to be dependent on the extent and nature of the amide distortion. We thus conclude that ring strain of these medium-sized heterocyclic rings is relieved through amide distortion, which leads to a more stable structure.
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Published date: 4 March 2005
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Local EPrints ID: 20891
URI: http://eprints.soton.ac.uk/id/eprint/20891
ISSN: 0022-3263
PURE UUID: 2faa436d-5861-496a-8669-9d93a5b0e5c7
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Date deposited: 02 Mar 2006
Last modified: 15 Mar 2024 06:26
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Author:
Maryiam Qadir
Author:
Jonathan Cobb
Author:
Peter W. Sheldrake
Author:
Neil Whittall
Author:
Andrew J.P. White
Author:
King Kuok (Mimi) Hii
Author:
Peter N. Horton
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