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Shoji T, Sasahara N, Hamasaki A, Mori S, Okujima T, Sekiguchi R, Ito S. Synthesis, Structural, and Optical Properties of Azuleno[1,2- c]pyran-1-ones: Bro̷nsted Acid-Mediated Cyclization of 2-Azulenylalkynes. J Org Chem 2023. [PMID: 37906944 DOI: 10.1021/acs.joc.3c01742] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2023]
Abstract
Pyrones and their aromatic ring-fused derivatives have gained significant attention due to their diverse biological activities and potential as foundational frameworks for advanced materials. In this paper, we describe a proficient approach for the preparation of azuleno[1,2-c]pyran-1-ones, which are difficult to produce by using conventional methods. The synthesis was achieved through Bro̷nsted acid-mediated cyclization of 2-azulenylalkynes. The structural and optical properties of azuleno[1,2-c]pyran-1-ones were characterized by single-crystal X-ray analysis, NMR, UV/vis, and fluorescence spectroscopies. Under acidic conditions, these compounds displayed notable spectral alterations and emission, distinct from their spectra in neutral medium. These results suggest that azuleno[1,2-c]pyran-1-ones hold great potential for applications in organic electronic materials and fluorescent pH sensors.
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Affiliation(s)
- Taku Shoji
- Department of Chemical Biology and Applied Chemistry, College of Engineering, Nihon University, Koriyama 963-8642, Japan
| | - Nichika Sasahara
- Graduate School of Science and Technology, Shinshu University, Matsumoto 390-8621, Japan
| | - Atom Hamasaki
- Graduate School of Science and Technology, Shinshu University, Matsumoto 390-8621, Japan
| | - Shigeki Mori
- Advanced Research Support Center, Ehime University, Matsuyama 790-8577, Japan
| | - Tetsuo Okujima
- Graduate School of Science and Engineering, Ehime University, Matsuyama 790-8577, Japan
| | - Ryuta Sekiguchi
- Graduate School of Science and Technology, Hirosaki University, Hirosaki 036-8561, Japan
| | - Shunji Ito
- Graduate School of Science and Technology, Hirosaki University, Hirosaki 036-8561, Japan
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Harabajiu C, Hann JL, Murfin LC, Kociok-Köhn G, Lewis SE. Persistent azulene α-carbocations: synthesis from aldehydes, spectroscopic and crystallographic properties. Org Biomol Chem 2023; 21:858-866. [PMID: 36602170 DOI: 10.1039/d2ob01695h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The non-benzenoid aromatic system azulene is sufficiently nucleophilic at C1 that it can react with a protonated aldehyde to form an α-azulenyl alcohol. This in turn may be protonated and undergo loss of water to give an azulene α-carbocation. We report the isolation of such azulenyl cations as salts with non-coordinating anions. The salts have been characterised by NMR, UV/Vis absorption and (in certain cases) X-ray crystallography. Reduction of representative salts to afford azulenyl(aryl) methylenes has been demonstrated.
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Affiliation(s)
| | - Jodie L Hann
- Department of Chemistry, University of Bath, Bath, BA2 7AY, UK.
| | - Lloyd C Murfin
- Department of Chemistry, University of Bath, Bath, BA2 7AY, UK.
| | - Gabriele Kociok-Köhn
- Material and Chemical Characterisation Facility (MC2), University of Bath, Bath, BA2 7AY, UK
| | - Simon E Lewis
- Department of Chemistry, University of Bath, Bath, BA2 7AY, UK.
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Elwahy AHM, Hafner K. Alkynylazulenes as Building Blocks for Highly Unsaturated Scaffolds. ASIAN J ORG CHEM 2021. [DOI: 10.1002/ajoc.202100301] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Affiliation(s)
| | - Klaus Hafner
- Clemens Schöpf-Institut für Organische Chemie und Biochemie Technische Universität, Darmstadt Petersenstraβe 22 D-64287 Darmstadt Germany
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Shoji T, Ariga Y, Yamazaki A, Uda M, Nagasawa T, Ito S. Synthesis, Photophysical and Electrochemical Properties of 1-, 2-, and 6-(2-Benzofuryl)azulenes. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2021. [DOI: 10.1246/bcsj.20200311] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Affiliation(s)
- Taku Shoji
- Graduate School of Science and Technology, Shinshu University, Matsumoto, Nagano 390-8621, Japam
| | - Yukino Ariga
- Graduate School of Science and Technology, Shinshu University, Matsumoto, Nagano 390-8621, Japam
| | - Akari Yamazaki
- Graduate School of Science and Technology, Shinshu University, Matsumoto, Nagano 390-8621, Japam
| | - Mayumi Uda
- Graduate School of Science and Technology, Shinshu University, Matsumoto, Nagano 390-8621, Japam
| | - Takuya Nagasawa
- Graduate School of Science and Technology, Hirosaki University, Hirosaki, Aomori 036-8561, Japam
| | - Shunji Ito
- Graduate School of Science and Technology, Hirosaki University, Hirosaki, Aomori 036-8561, Japam
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Development of Heterocycle-Substituted and Fused Azulenes in the Last Decade (2010-2020). Int J Mol Sci 2020; 21:ijms21197087. [PMID: 32992955 PMCID: PMC7582284 DOI: 10.3390/ijms21197087] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 09/22/2020] [Accepted: 09/22/2020] [Indexed: 02/06/2023] Open
Abstract
Azulene derivatives with heterocyclic moieties in the molecule have been synthesized for applications in materials science by taking advantage of their unique properties. These derivatives have been prepared by various methods, involving electrophilic substitution, condensation, cyclization, and transition metal-catalyzed cross-coupling reactions. Herein, we present the development of the synthetic methods, reactivities, and physical properties for the heterocycle-substituted and heterocycle-fused azulenes reported in the last decade.
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Kogawa C, Fujiwara A, Sekiguchi R, Shoji T, Kawakami J, Okazaki M, Ito S. Synthesis and photophysical properties of azuleno[1′,2′:4,5]pyrrolo[2,1-b]quinazoline-6,14-diones: Azulene analogs of tryptanthrin. Tetrahedron 2018. [DOI: 10.1016/j.tet.2018.10.020] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Razus AC, Birzan L. Synthesis of azulenic compounds substituted in the 1-position with heterocycles. MONATSHEFTE FUR CHEMIE 2018. [DOI: 10.1007/s00706-018-2294-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Affiliation(s)
- Giulia Oss
- School of Chemistry University of New South Wales Sydney Australia
| | - Junming Ho
- School of Chemistry University of New South Wales Sydney Australia
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Shoji T, Ito S. The Preparation and Properties of Heteroarylazulenes and Hetero-Fused Azulenes. ADVANCES IN HETEROCYCLIC CHEMISTRY 2018. [DOI: 10.1016/bs.aihch.2018.02.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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Shoji T, Tanaka M, Takagaki S, Miura K, Ohta A, Sekiguchi R, Ito S, Mori S, Okujima T. Synthesis of azulene-substituted benzofurans and isocoumarins via intramolecular cyclization of 1-ethynylazulenes, and their structural and optical properties. Org Biomol Chem 2018; 16:480-489. [PMID: 29270584 DOI: 10.1039/c7ob02861j] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The preparation of azulene-substituted benzofurans and isocoumarins was established by two types of intramolecular cyclization reaction of 1-ethynylazulenes.
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Affiliation(s)
- Taku Shoji
- Graduate School of Science and Technology
- Shinshu University
- Matsumoto
- Japan
| | - Miwa Tanaka
- Graduate School of Science and Technology
- Shinshu University
- Matsumoto
- Japan
| | - Sho Takagaki
- Graduate School of Science and Technology
- Shinshu University
- Matsumoto
- Japan
| | - Kota Miura
- Graduate School of Science and Technology
- Shinshu University
- Matsumoto
- Japan
| | - Akira Ohta
- Graduate School of Science and Technology
- Shinshu University
- Matsumoto
- Japan
| | - Ryuta Sekiguchi
- Graduate School of Science and Technology
- Shinshu University
- Matsumoto
- Japan
| | - Shunji Ito
- Graduate School of Science and Technology
- Hirosaki University
- Hirosaki 036-8561
- Japan
| | - Shigeki Mori
- Advanced Research Support Center
- Ehime University
- Matsuyama 790-8577
- Japan
| | - Tetsuo Okujima
- Department of Chemistry and Biology
- Graduate School of Science and Engineering
- Ehime University
- Matsuyama 790-8577
- Japan
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Shoji T, Sugiyama S, Araki T, Ohta A, Sekiguchi R, Ito S, Mori S, Okujima T, Yasunami M. Synthesis of 2-amino- and 2-arylazoazulenes via nucleophilic aromatic substitution of 2-chloroazulenes with amines and arylhydrazines. Org Biomol Chem 2017; 15:3917-3923. [PMID: 28426084 DOI: 10.1039/c7ob00691h] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The SNAr reaction of 2-chloroazulene derivative 1 with ethoxycarbonyl groups at the 1,3-positions of the azulene ring with several amines afforded the corresponding 2-aminoazulenes 3-9 in excellent yields. 2-Chloroazulene (2) without the electron-withdrawing groups reacted with highly nucleophilic cyclic amines (i.e., morpholine, piperidine and pyrrolidine) under the high-temperature conditions in a sealed tube to produce the corresponding 2-aminoazulenes 10-12 in good yields. 2-Aminoazulenes 10-14 without the electron-withdrawing groups were also obtained in good yields by the treatment of compounds 3-7 with 100% H3PO4, but in the cases of the reaction of 8 and 9 with a secondary amine function, the decomposition of the products resulted. The synthesis of 2-arylazoazulenes 15-18 was also established via the SNAr reaction of 1 with arylhydrazines. The optical and electrochemical properties of the 2-arylazoazulene derivatives were examined by UV/Vis spectroscopy, theoretical calculations and voltammetric experiments.
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Affiliation(s)
- Taku Shoji
- Graduate School of Science and Technology, Shinshu University, Matsumoto, 390-8621, Nagano, Japan.
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Shoji T, Takagaki S, Tanaka M, Araki T, Sugiyama S, Sekiguchi R, Ohta A, Ito S, Okujima T. Synthesis of Azulene-Substituted Tetraarylpyrroles by Reaction of 1-Azulenyl Ketones with Benzoin and Ammonium Acetate. HETEROCYCLES 2017. [DOI: 10.3987/com-17-13781] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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