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Ito A, Asato M, Asami Y, Fukuda K, Yamasaki R, Okamoto I. Synthesis and Conformational Analysis of N-Aromatic Acetamides Bearing Thiophene: Effect of Intramolecular Chalcogen-Chalcogen Interaction on Amide Conformational Stability. J Org Chem 2023. [PMID: 37154822 DOI: 10.1021/acs.joc.3c00345] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
The conformations of aromatic amides bearing an N-(2-thienyl) or N-(3-thienyl) group were investigated in solution and in the crystal state. NMR spectral data indicate that the conformational preferences of these amides in solution are dependent not only on the relative π-electron densities of the N-aromatic moieties, but also on the three-dimensional relationship between carbonyl oxygen and the N-aromatic moieties. A comparison of the conformational preferences of N-(2-thienyl)amides and N-(3-thienyl)amides revealed that the Z-conformers of N-(2-thienyl)acetamides are stabilized by 1,5-type intramolecular S···O═C interactions between amide carbonyl and thiophene sulfur. The crystal structures of these compounds were similar to the solution structures. The stabilization energy due to 1,5-type intramolecular S···O═C interaction in N-aryl-N-(2-thienyl)acetamides and N-methyl-N-(2-thienyl)acetamide was estimated to be ca. 0.74 and 0.93 kcal/mol, respectively.
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Affiliation(s)
- Ai Ito
- Showa Pharmaceutical University, 3-3165 Higashi-Tamagawagakuen, Machida, Tokyo 194-8543, Japan
| | - Marino Asato
- Showa Pharmaceutical University, 3-3165 Higashi-Tamagawagakuen, Machida, Tokyo 194-8543, Japan
| | - Yuki Asami
- Showa Pharmaceutical University, 3-3165 Higashi-Tamagawagakuen, Machida, Tokyo 194-8543, Japan
| | - Kazuo Fukuda
- Showa Pharmaceutical University, 3-3165 Higashi-Tamagawagakuen, Machida, Tokyo 194-8543, Japan
| | - Ryu Yamasaki
- Showa Pharmaceutical University, 3-3165 Higashi-Tamagawagakuen, Machida, Tokyo 194-8543, Japan
| | - Iwao Okamoto
- Showa Pharmaceutical University, 3-3165 Higashi-Tamagawagakuen, Machida, Tokyo 194-8543, Japan
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Elwahy AHM, Shaaban MR, Abdelhamid IA. Recent Advances in the Functionalization of Azulene Through Rh‐, Ir‐, Ru‐, Au‐, Fe‐, Ni‐, and Cu‐catalyzed Reactions. Appl Organomet Chem 2022. [DOI: 10.1002/aoc.6772] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
| | - Mohamed R. Shaaban
- Chemistry Department, Faculty of Applied Sciences, Makkah Almukkarramah, Umm AL‐Qura University Saudi Arabia
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Synthesis and crystal structures of N,N-diarylacetamides bearing two azulene rings. Tetrahedron Lett 2021. [DOI: 10.1016/j.tetlet.2021.153523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Yamasaki R, Morita K, Iizumi H, Ito A, Fukuda K, Okamoto I. N-Ethynylation of Anilides Decreases the Double-Bond Character of Amide Bond while Retaining trans-Conformation and Planarity. Chemistry 2019; 25:10118-10122. [PMID: 31050845 DOI: 10.1002/chem.201901451] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Revised: 04/20/2019] [Indexed: 11/08/2022]
Abstract
Activated amide bonds have been attracting intense attention; however, most of the studied moieties have twisted amide character. To add a new strategy to activate amide bonds while maintaining its planarity, we envisioned the introduction of an alkynyl group on the amide nitrogen to disrupt amide resonance by nN→Csp conjugation. In this context, the conformations and properties of N-ethynyl-substituted aromatic amides were investigated by DFT calculations, crystallography, and NMR spectroscopic analysis. In contrast to the cis conformational preference of N-ethyl- and vinyl-substituted acetanilides, N-ethynyl-substituted acetanilide favors the trans conformation in the crystal and in solution. It also has a decreased double bond character of the C(O)-N bond, without twisting of the amide. N-Ethynyl-substituted acetanilides undergo selective C(O)-N bond or N-C(sp) bond cleavage reactions and have potential applications as activated amides for coupling reactions or easily cleavable tethers.
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Affiliation(s)
- Ryu Yamasaki
- Showa Pharmaceutical University, 3-3165 Higashi-Tamagawagakuen, Machida, Tokyo, 194-8543, Japan
| | - Kento Morita
- Showa Pharmaceutical University, 3-3165 Higashi-Tamagawagakuen, Machida, Tokyo, 194-8543, Japan
| | - Hiromi Iizumi
- Showa Pharmaceutical University, 3-3165 Higashi-Tamagawagakuen, Machida, Tokyo, 194-8543, Japan
| | - Ai Ito
- Showa Pharmaceutical University, 3-3165 Higashi-Tamagawagakuen, Machida, Tokyo, 194-8543, Japan
| | - Kazuo Fukuda
- Showa Pharmaceutical University, 3-3165 Higashi-Tamagawagakuen, Machida, Tokyo, 194-8543, Japan
| | - Iwao Okamoto
- Showa Pharmaceutical University, 3-3165 Higashi-Tamagawagakuen, Machida, Tokyo, 194-8543, Japan
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Tojo Y, Urushibara K, Yamamoto S, Mori H, Masu H, Kudo M, Hirano T, Azumaya I, Kagechika H, Tanatani A. Conformational Properties of Aromatic Oligoamides Bearing Pyrrole Rings. J Org Chem 2018; 83:4606-4617. [DOI: 10.1021/acs.joc.8b00349] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Yukiko Tojo
- Department of Chemistry, Faculty of Science, Ochanomizu University, 2-1-1 Otsuka, Bunkyo-ku, Tokyo 112-8610, Japan
| | - Ko Urushibara
- Department of Chemistry, Faculty of Science, Ochanomizu University, 2-1-1 Otsuka, Bunkyo-ku, Tokyo 112-8610, Japan
| | - Sawori Yamamoto
- Department of Chemistry, Faculty of Science, Ochanomizu University, 2-1-1 Otsuka, Bunkyo-ku, Tokyo 112-8610, Japan
| | - Hirotoshi Mori
- Department of Chemistry, Faculty of Science, Ochanomizu University, 2-1-1 Otsuka, Bunkyo-ku, Tokyo 112-8610, Japan
| | - Hyuma Masu
- Center for Analytical Instrumentation, Chiba University, Yayoi-cho, Chiba-shi, Chiba 263-8522, Japan
| | - Mayumi Kudo
- Department of Chemistry, Faculty of Science, Ochanomizu University, 2-1-1 Otsuka, Bunkyo-ku, Tokyo 112-8610, Japan
| | - Tomoya Hirano
- Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, 2-3-10 Kanda-Surugadai, Chiyoda-ku, Tokyo 101-0062, Japan
| | - Isao Azumaya
- Faculty of Pharmaceutical Sciences, Toho University, 2-2-1 Miyama, Funabashi, Chiba 274-8510, Japan
| | - Hiroyuki Kagechika
- Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, 2-3-10 Kanda-Surugadai, Chiyoda-ku, Tokyo 101-0062, Japan
| | - Aya Tanatani
- Department of Chemistry, Faculty of Science, Ochanomizu University, 2-1-1 Otsuka, Bunkyo-ku, Tokyo 112-8610, Japan
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Ito A, Fujino H, Ushiyama K, Yamanaka E, Yamasaki R, Okamoto I. Acid-controlled switching of conformational preference of N,N-diarylamides bearing pyridine. Tetrahedron Lett 2016. [DOI: 10.1016/j.tetlet.2016.09.035] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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