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Shoji T, Yamazaki A, Katoh R, Shimamura K, Sakai R, Yasunami M, Okujima T, Ito S. Synthesis, Reactivity, and Properties of Benz[ a]azulenes via the [8 + 2] Cycloaddition of 2 H-Cyclohepta[ b]furan-2-ones with an Enamine. J Org Chem 2022; 87:5827-5845. [PMID: 35420822 DOI: 10.1021/acs.joc.2c00133] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Starting with the reaction of 2H-cyclohepta[b]furan-2-ones with an enamine, which was prepared from 4-tert-butylcyclohexanone and pyrrolidine, benz[a]azulenes having both formyl and tert-butyl groups were obtained in the three-step sequence. Subsequently, both the formyl and tert-butyl groups were eliminated by heating the benz[a]azulene derivatives in 100% H3PO4 to give benz[a]azulenes without these substituents in high yields. In terms of product yield, this method is the best one ever reported for the synthesis of the parent benz[a]azulene so far. The conversion of the benz[a]azulene derivatives with a formyl group into cyclohept[a]acenaphthylen-3-one derivatives was also investigated via Knoevenagel condensation with dimethyl malonate, followed by Brønsted acid-mediated intramolecular cyclization. The structural features including the bond alternation in the benz[a]azulene derivatives were revealed by NMR studies, NICS calculations, and a single-crystal X-ray structural analysis. The optical and electrochemical properties of a series of benz[a]azulene derivatives were evaluated by UV/Vis, fluorescence spectroscopy, and voltammetry experiments. As a result, we found that some benz[a]azulene derivatives showed remarkable luminescence in acidic media. In addition, the benz[a]azulene derivatives with the electron-withdrawing group and cyclohept[a]acenaphthylen-3-one derivative displayed good reversibility in the spectral changes under the electrochemical redox conditions.
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Affiliation(s)
- Taku Shoji
- Graduate School of Science and Technology, Shinshu University, Matsumoto 390-8621, Japan.,Department of Chemical Biology and Applied Chemistry, College of Engineering, Nihon University, Koriyama 963-8642, Japan
| | - Akari Yamazaki
- Graduate School of Science and Technology, Shinshu University, Matsumoto 390-8621, Japan
| | - Ryuzi Katoh
- Department of Chemical Biology and Applied Chemistry, College of Engineering, Nihon University, Koriyama 963-8642, Japan
| | - Konomi Shimamura
- Department of Chemical Biology and Applied Chemistry, College of Engineering, Nihon University, Koriyama 963-8642, Japan
| | - Rina Sakai
- Department of Chemical Biology and Applied Chemistry, College of Engineering, Nihon University, Koriyama 963-8642, Japan
| | - Masafumi Yasunami
- Department of Chemical Biology and Applied Chemistry, College of Engineering, Nihon University, Koriyama 963-8642, Japan
| | - Tetsuo Okujima
- Department of Chemistry and Biology, Graduate School of Science and Engineering, Ehime University, Matsuyama 790-8577, Japan
| | - Shunji Ito
- Graduate School of Science and Technology, Hirosaki University, Hirosaki 036-8561, Japan
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Awuku S, Bradley SJ, Ghiggino KP, Steer RP, Stevens AL, White JM, Yeow C. Photophysics and spectroscopy of 1,2-Benzazulene. Chem Phys Lett 2021. [DOI: 10.1016/j.cplett.2021.139114] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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Steer RP. Photophysics of molecules containing multiples of the azulene carbon framework. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY C: PHOTOCHEMISTRY REVIEWS 2019. [DOI: 10.1016/j.jphotochemrev.2019.06.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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Muller PA, Vauthey E. Charge Recombination Dynamics of Geminate Ion Pairs Formed by Electron Transfer Quenching of Molecules in an Upper Excited State. J Phys Chem A 2001. [DOI: 10.1021/jp010015z] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Pierre-Alain Muller
- Institut de Chimie-Physique de l'Université de Fribourg, Pérolles, CH-1700 Fribourg, Switzerland
| | - Eric Vauthey
- Institut de Chimie-Physique de l'Université de Fribourg, Pérolles, CH-1700 Fribourg, Switzerland
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Yamaguchi H, Ata M, Toyoda K, Mametsuka H, Takeshita H, Baumann H. Magnetic Circular Dichroism and Absorption Spectra of 2-Methyl-1, 3-diazaazulene. Helv Chim Acta 1981. [DOI: 10.1002/hlca.19810640741] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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