Synthesis of Azuleno[2,1-<i>b</i>]quinolones and Quinolines via Brønsted Acid-Catalyzed Cyclization of 2-Arylaminoazulenes
Quinolone and quinoline derivatives are frequently found as substructures in pharmaceutically active compounds. In this paper, we describe a procedure for the synthesis of azuleno[2,1-<i>b</i>]quinolones and quinolines from 2-arylaminoazulene derivatives, which are readily prepared via t...
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MDPI AG
2023-07-01
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| author | Taku Shoji Mutsumi Takeuchi Mayumi Uda Yukino Ariga Akari Yamazaki Ryuta Sekiguchi Shunji Ito |
| author_facet | Taku Shoji Mutsumi Takeuchi Mayumi Uda Yukino Ariga Akari Yamazaki Ryuta Sekiguchi Shunji Ito |
| author_sort | Taku Shoji |
| collection | DOAJ |
| description | Quinolone and quinoline derivatives are frequently found as substructures in pharmaceutically active compounds. In this paper, we describe a procedure for the synthesis of azuleno[2,1-<i>b</i>]quinolones and quinolines from 2-arylaminoazulene derivatives, which are readily prepared via the aromatic nucleophilic substitution reaction of a 2-chloroazulene derivative with several arylamines. The synthesis of azuleno[2,1-<i>b</i>]quinolones was established by the Brønsted acid-catalyzed intramolecular cyclization of 2-arylaminoazulene derivatives bearing two ester groups at the five-membered ring. The halogenative aromatization of azuleno[2,1-<i>b</i>]quinolones with POCl<sub>3</sub> yielded azuleno[2,1-<i>b</i>]quinolines with a chlorine substituent at the pyridine moiety. The aromatic nucleophilic substitution reaction of azuleno[2,1-<i>b</i>]quinolines bearing chlorine substituent with secondary amines was also investigated to afford the aminoquinoline derivatives. These synthetic methodologies reported in this paper should be valuable in the development of new pharmaceuticals based on the azulene skeleton. |
| first_indexed | 2024-03-11T00:20:30Z |
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| issn | 1420-3049 |
| language | English |
| last_indexed | 2024-03-11T00:20:30Z |
| publishDate | 2023-07-01 |
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| spelling | doaj.art-5ff5ea76477c4bcab56a11404983f16f2023-11-18T23:18:51ZengMDPI AGMolecules1420-30492023-07-012815578510.3390/molecules28155785Synthesis of Azuleno[2,1-<i>b</i>]quinolones and Quinolines via Brønsted Acid-Catalyzed Cyclization of 2-ArylaminoazulenesTaku Shoji0Mutsumi Takeuchi1Mayumi Uda2Yukino Ariga3Akari Yamazaki4Ryuta Sekiguchi5Shunji Ito6Department of Chemical Biology and Applied Chemistry, College of Engineering, Nihon University, Koriyama 963-8642, JapanGraduate School of Science and Technology, Shinshu University, Matsumoto 390-8621, JapanGraduate School of Science and Technology, Shinshu University, Matsumoto 390-8621, JapanGraduate School of Science and Technology, Shinshu University, Matsumoto 390-8621, JapanGraduate School of Science and Technology, Shinshu University, Matsumoto 390-8621, JapanGraduate School of Science and Technology, Hirosaki University, Hirosaki 036-8561, JapanGraduate School of Science and Technology, Hirosaki University, Hirosaki 036-8561, JapanQuinolone and quinoline derivatives are frequently found as substructures in pharmaceutically active compounds. In this paper, we describe a procedure for the synthesis of azuleno[2,1-<i>b</i>]quinolones and quinolines from 2-arylaminoazulene derivatives, which are readily prepared via the aromatic nucleophilic substitution reaction of a 2-chloroazulene derivative with several arylamines. The synthesis of azuleno[2,1-<i>b</i>]quinolones was established by the Brønsted acid-catalyzed intramolecular cyclization of 2-arylaminoazulene derivatives bearing two ester groups at the five-membered ring. The halogenative aromatization of azuleno[2,1-<i>b</i>]quinolones with POCl<sub>3</sub> yielded azuleno[2,1-<i>b</i>]quinolines with a chlorine substituent at the pyridine moiety. The aromatic nucleophilic substitution reaction of azuleno[2,1-<i>b</i>]quinolines bearing chlorine substituent with secondary amines was also investigated to afford the aminoquinoline derivatives. These synthetic methodologies reported in this paper should be valuable in the development of new pharmaceuticals based on the azulene skeleton.https://www.mdpi.com/1420-3049/28/15/5785azulenequinolonequinolinecyclizationaromatic nucleophilic substitution |
| spellingShingle | Taku Shoji Mutsumi Takeuchi Mayumi Uda Yukino Ariga Akari Yamazaki Ryuta Sekiguchi Shunji Ito Synthesis of Azuleno[2,1-<i>b</i>]quinolones and Quinolines via Brønsted Acid-Catalyzed Cyclization of 2-Arylaminoazulenes Molecules azulene quinolone quinoline cyclization aromatic nucleophilic substitution |
| title | Synthesis of Azuleno[2,1-<i>b</i>]quinolones and Quinolines via Brønsted Acid-Catalyzed Cyclization of 2-Arylaminoazulenes |
| title_full | Synthesis of Azuleno[2,1-<i>b</i>]quinolones and Quinolines via Brønsted Acid-Catalyzed Cyclization of 2-Arylaminoazulenes |
| title_fullStr | Synthesis of Azuleno[2,1-<i>b</i>]quinolones and Quinolines via Brønsted Acid-Catalyzed Cyclization of 2-Arylaminoazulenes |
| title_full_unstemmed | Synthesis of Azuleno[2,1-<i>b</i>]quinolones and Quinolines via Brønsted Acid-Catalyzed Cyclization of 2-Arylaminoazulenes |
| title_short | Synthesis of Azuleno[2,1-<i>b</i>]quinolones and Quinolines via Brønsted Acid-Catalyzed Cyclization of 2-Arylaminoazulenes |
| title_sort | synthesis of azuleno 2 1 i b i quinolones and quinolines via bronsted acid catalyzed cyclization of 2 arylaminoazulenes |
| topic | azulene quinolone quinoline cyclization aromatic nucleophilic substitution |
| url | https://www.mdpi.com/1420-3049/28/15/5785 |
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