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Yan J, Zheng X, Zheng Y, Zhan R, Huang H. Asymmetric Michael reaction of 3-homoacyl coumarins with chromone-fused dienes toward enantioenriched coumarin chromone skeletons. Org Biomol Chem 2021; 19:8102-8107. [PMID: 34494052 DOI: 10.1039/d1ob01200b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Asymmetric Michael reaction of 3-homoacyl coumarins and chromone-fused dienes was developed by employing a chiral squaramide, and a series of coumarin chromone skeletons were furnished in moderate to high yields (up to 99%) and stereoselectivities (up to 98 : 2 dr, 99% ee).
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Affiliation(s)
- Juzhang Yan
- Key Laboratory of Chinese Medicinal Resource from Lingnan, Ministry of Education, School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, Guangzhou, 510006, P. R. China.
| | - Xiurong Zheng
- Key Laboratory of Chinese Medicinal Resource from Lingnan, Ministry of Education, School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, Guangzhou, 510006, P. R. China.
| | - Yangqing Zheng
- Key Laboratory of Chinese Medicinal Resource from Lingnan, Ministry of Education, School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, Guangzhou, 510006, P. R. China.
| | - Ruoting Zhan
- Key Laboratory of Chinese Medicinal Resource from Lingnan, Ministry of Education, School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, Guangzhou, 510006, P. R. China.
| | - Huicai Huang
- Key Laboratory of Chinese Medicinal Resource from Lingnan, Ministry of Education, School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, Guangzhou, 510006, P. R. China.
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Bieniek N, Inacker S, Hampp N. Cycloreversion performance of coumarin and hetero-coumarin dimers under aerobic conditions: unexpected behavior triggered by UV-A light. Phys Chem Chem Phys 2021; 23:17703-17712. [PMID: 34374390 DOI: 10.1039/d1cp01919h] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Photochemical [2+2]-cycloadditions of coumarin-like monomers are the textbook paradigms of photo-formation and photo-cleavage reactions. The electronic conjugation length of monomers and dimers is quite different which results in almost fully separated UV/Vis absorption bands in the UV-A and UV-C. This feature enables the selective light-controlled conversion between monomeric and dimeric forms by the choice of the appropriate wavelengths. Several applications are based on this kind of reversible photo linker without absorption in the visible range. But which is the best molecule from the coumarin family for such an application? Within this study, we compared the photochemical cleavage behavior of twelve coumarin-type cyclobutane dimers. In particular, the influence of isomer structure and substitution pattern was studied. Two dimers with an unexpected high quantum yield for cyclobutane cleavage were identified. This behavior is explained through the differing ring strain of the cyclobutane moiety. Electron donating substitutions of the framework, e.g. with a methoxy function (+M-effect), leads to a decreased oxidation potential, making the dimers sensitive towards oxidative dimer splitting. This result disqualifies coumarins, e.g. attached to a polymer backbone via an ether bond, often in the 7-position, because of their instabilities and side reactions in an aerobic environment. The methylated dimers (+I-effect) show excellent stability towards this undesired side reaction as well as a high cleavage efficiency upon irradiation with 265 nm. All twelve investigated dimers are ranked for their quantum efficiency and rate constant for cleavage at 265 nm, as well as their oxygen tolerance. As the most promising derivative within our scope for applications the methylated coumarin dimer was identified.
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Affiliation(s)
- Nikolai Bieniek
- Department of Chemistry, University of Marburg, Hans-Meerwein-Straße 4, D-35032 Marburg, Germany.
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Herman J, Neal SL. Efficiency comparison of the imidazole plus RNO method for singlet oxygen detection in biorelevant solvents. Anal Bioanal Chem 2019; 411:5287-96. [DOI: 10.1007/s00216-019-01910-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 05/03/2019] [Accepted: 05/09/2019] [Indexed: 10/26/2022]
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Affiliation(s)
- Huen Ji Yoo
- Center for New Directions in Organic Synthesis, Department of Chemistry and Research Institute for Natural Sciences, Hanyang University, Seoul 04763, Korea
| | - So Won Youn
- Center for New Directions in Organic Synthesis, Department of Chemistry and Research Institute for Natural Sciences, Hanyang University, Seoul 04763, Korea
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Liu ZH, Li DJ, Jiang D, Xiao C, Song ZG, Jin YH. Design, synthesis and antitumor activity in vitro of a series of 3-arylcoumarins. Chem Res Chin Univ 2013. [DOI: 10.1007/s40242-013-3107-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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Jiang Y, Chen W, Lu W. Synthesis of 3-arylcoumarins through N-heterocyclic carbene catalyzed condensation and annulation of 2-chloro-2-arylacetaldehydes with salicylaldehydes. Tetrahedron 2013; 69:3669-76. [DOI: 10.1016/j.tet.2013.03.025] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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Abstract
The unique ability of nitrone spin traps to detect and characterize transient free radicals by electron paramagnetic resonance (EPR) spectroscopy has fueled the development of new spin traps with improved properties. Among a variety of free radicals in chemical and biological systems, superoxide radical anion (O(2)(•-)) plays a critical role as a precursor to other more oxidizing species such as hydroxyl radical (HO(•)), peroxynitrite (ONOO(-)), and hypochlorous acid (HOCl), and therefore the direct detection of O(2)(•-) is important. To overcome the limitations of conventional cyclic nitrones, that is, poor reactivity with O(2)(•-), instability of the O(2)(•-) adduct, and poor cellular target specificity, synthesis of disubstituted nitrones has become attractive. Disubstituted nitrones offer advantages over the monosubstituted ones because they allow bifunctionalization of spin traps, therefore accommodating all the desired spin trap properties in one molecular design. However, because of the high number of possible disubstituted analogues as candidate, a systematic computational study is needed to find leads for the optimal spin trap design for biconjugation. In this paper, calculation of the energetics of O(2)(•-) and HO(2)(•) adduct formation from various disubstituted nitrones at PCM/B3LYP/6-31+G(d,p)//B3LYP/6-31G(d) level of theory was performed to determine the most favorable disubstituted nitrones for this reaction. In addition, our results provided general trends of radical reactivity that is dependent upon but not exclusive to the charge densities of nitronyl-C, the position of substituents including stereoselectivities, and the presence of intramolecular H-bonding interaction. Unusually high exoergic ΔG(298K,aq)'s for O(2)(•-) and HO(2)(•) adduct formation were predicted for (3S,5S)-5-methyl-3,5-bis(methylcarbamoyl)-1-pyrroline N-oxide (11-cis) and (4S,5S)-5-dimethoxyphosphoryl-5-methyl-4-ethoxycarbonyl-1-pyrroline N-oxide (29-trans) with ΔG(298K,aq) = -3.3 and -9.4 kcal/mol, respectively, which are the most exoergic ΔG(298K,aq) observed thus far for any nitrone at the level of theory employed in this study.
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Affiliation(s)
- Shang-U Kim
- Department of Pharmacology and Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, OH, 43210
| | - Frederick A. Villamena
- Department of Pharmacology and Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, OH, 43210
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Kim SU, Liu Y, Nash KM, Zweier JL, Rockenbauer A, Villamena FA. Fast reactivity of a cyclic nitrone-calix[4]pyrrole conjugate with superoxide radical anion: theoretical and experimental studies. J Am Chem Soc 2010; 132:17157-73. [PMID: 21070040 PMCID: PMC3121924 DOI: 10.1021/ja105198c] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Nitrone spin traps have been employed as probes for the identification of transient radical species in chemical and biological systems using electron paramagnetic resonance (EPR) spectroscopy and have exhibited pharmacological activity against oxidative-stress-mediated diseases. Since superoxide radical anion (O2(•-)) is a major precursor to most reactive oxygen species and calix[4]pyrroles have been shown to exhibit high affinity to anions, a cyclic nitrone conjugate of calix[4]pyrrole (CalixMPO) was designed, synthesized, and characterized. Computational studies at the PCM/B3LYP/6-31+G(d,p)//B3LYP/6-31G(d) level suggest a pendant-type linkage between the calix[4]pyrrole and the nitrone to be the most efficient design for spin trapping of O2(•-), giving exoergic reaction enthalpies (ΔH(298K,aq)) and free energies (ΔG(298K,aq)) of -16.9 and -2.1 kcal/mol, respectively. (1)H NMR study revealed solvent-dependent conformational changes in CalixMPO leading to changes in the electronic properties of the nitronyl group upon H-bonding with the pyrrole groups as also confirmed by calculations. CalixMPO spin trapping of O2(•-) exhibited robust EPR spectra. Kinetic analysis of O2(•-) adduct formation and decay in polar aprotic solvents using UV-vis stopped-flow and EPR methods gave a larger trapping rate constant for CalixMPO and a longer half-life for its O2(•-) adduct compared to the commonly used nitrones. The unusually high reactivity of CalixMPO with O2(•-) was rationalized to be due to the synergy between the α-effect and electrostatic effect by the calix[4]pyrrole moiety on O2(•-) and the nitrone, respectively. This work demonstrates for the first time the application of an anion receptor for the detection of one of the most important radical intermediates in biological and chemical systems (i.e., O2(•-)).
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Affiliation(s)
- Shang-U Kim
- Department of Pharmacology, Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, OH, 43210, USA
- Center for Biomedical EPR Spectroscopy and Imaging, Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, OH, 43210, USA
| | - Yangping Liu
- Center for Biomedical EPR Spectroscopy and Imaging, Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, OH, 43210, USA
| | - Kevin M. Nash
- Department of Pharmacology, Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, OH, 43210, USA
| | - Jay L. Zweier
- Center for Biomedical EPR Spectroscopy and Imaging, Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, OH, 43210, USA
| | - Antal Rockenbauer
- Chemical Research Center, Institute of Structural Chemistry, H-1025 Budapest, Pusztaszeri 59, Hungary
| | - Frederick A. Villamena
- Department of Pharmacology, Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, OH, 43210, USA
- Center for Biomedical EPR Spectroscopy and Imaging, Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, OH, 43210, USA
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Cigáň M, Gáplovský A, Gajdoš P, Magdolen P, Zahradník P, Vetríková Z. Photophysical properties and photostability of novel benzothiazole-based D-π-A-π-D systems. Spectrochim Acta A Mol Biomol Spectrosc 2010; 77:984-993. [PMID: 20863742 DOI: 10.1016/j.saa.2010.08.035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2010] [Accepted: 08/19/2010] [Indexed: 05/29/2023]
Abstract
The photophysical properties and photochemical stability of two novel D-π-A-π-D systems based on a benzothiazole core and terminal N,N-dimethylaminophenyl and N,N-diphenylaminophenyl groups were investigated. The quantum yield of photoreactions (Φ) was determined for various oxygen concentrations in the solvent (CH2Cl2) and various irradiation wavelengths. Trans-cis photoisomerization is proposed as a photobleaching mechanism during irradiation at longer wavelength due to charge-transfer transitions. Solution deoxygenation led to an unusual decrease in the photostability of the compounds investigated, most likely because of cation radical formation. The population of higher excited states for short-wavelength irradiation opened another degradation pathway and the overall degradation percentage decreased in comparison with long-wavelength irradiation. We assume that photoisomerization of the second double bond and electron transfer to CH2Cl2 (and subsequent oxidation reactions) contribute to this slower degradation branch. Singlet oxygen contributes significantly, albeit to the smallest values of Φ, to the overall photodegradation for both types of irradiation.
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Affiliation(s)
- Marek Cigáň
- Institute of Chemistry, Department of Organic Chemistry, Faculty of Natural Sciences, Comenius University, SK-842 15 Bratislava, Slovakia.
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Diaz-Uribe CE, Daza MC, Martínez F, Páez-Mozo EA, Guedes CL, Di Mauro E. Visible light superoxide radical anion generation by tetra(4-carboxyphenyl)porphyrin/TiO2: EPR characterization. J Photochem Photobiol A Chem 2010. [DOI: 10.1016/j.jphotochem.2010.08.013] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Han Y, Liu Y, Rockenbauer A, Zweier JL, Durana G, Villamena FA. Lipophilic beta-cyclodextrin cyclic-nitrone conjugate: synthesis and spin trapping studies. J Org Chem 2009; 74:5369-80. [PMID: 19530689 PMCID: PMC2736355 DOI: 10.1021/jo900856x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Nitrone spin traps are commonly employed as probes for the identification of transient radicals in chemical and biological systems using electron paramagnetic resonance (EPR) spectroscopy. Nitrones have also found applications as therapeutic agent in the treatment of radical-mediated diseases. Therefore, a spin trap that incorporates high reactivity to superoxide radical anion (O2(*-)), more persistent superoxide adduct, enhanced bioavailability, and selective targeting in one molecular design is desirable. In this work, the synthesis of a nitrone spin trap, 4, that is tethered via amide bonds to a beta-cyclodextrin (beta-CD) and a dodecyl chain was achieved with the expectation that the beta-cyclodextrin would lead to increased reactivity to O2(*-) and persistent O2(*-) adduct while the lipophilic chain would impart membrane targeting property. The two constitutional racemic isomers, 4a and 4b, were separated using preparative HPLC, and structural analysis and self-aggregation properties were carried out using NMR, induced circular dichroism, dynamic light scattering, transmission electron microscopy, and computational approach. EPR spin trapping of O2(*-) by 4a and 4b was only successful in DMSO and not in an aqueous system, due most likely to the amphiphilic character of 4 that can favor conformations (or aggregation) hindering radical addition to nitrone. Kinetics of formation and decay of the 4a-O2H adduct in polar aprotic solvents show faster reactivity to O2(*-) and more persistent O2(*-) adduct compared to nitrones not conjugated to beta-CD. Computational analysis of 4a and 4b as well as 4a-OOH and 4b-OOH adducts were carried out, and results show that isomerism, both constitutional and stereochemical, affects the orientations of aminoxyl-NO and/or hydroperoxyl groups relative to the beta-CD annulus for optimal H-bond interaction and stability.
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Affiliation(s)
- Yongbin Han
- Department of Pharmacology, The Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, OH 43210
| | - Yangping Liu
- Center for Biomedical EPR Spectroscopy and Imaging, The Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, OH 43210
| | - Antal Rockenbauer
- Chemical Research Center, Institute of Structural Chemistry, H-1025 Budapest, Pusztaszeri 59, Hungary
| | - Jay L. Zweier
- Center for Biomedical EPR Spectroscopy and Imaging, The Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, OH 43210
| | - Grégory Durana
- Laboratoire de Chimie BioOrganique et des Systèmes Moléculaires Vectoriels, Faculté des Sciences, Université d’Avignon et des Pays de Vaucluse, 33 Rue Louis Pasteur, 84000 Avignon, France
| | - Frederick A. Villamena
- Department of Pharmacology, The Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, OH 43210
- Center for Biomedical EPR Spectroscopy and Imaging, The Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, OH 43210
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Villamena FA, Liu Y, Zweier JL. Superoxide radical anion adduct of 5,5-dimethyl-1-pyrroline N-oxide. 4. Conformational effects on the EPR hyperfine splitting constants. J Phys Chem A 2009; 112:12607-15. [PMID: 19012384 DOI: 10.1021/jp8070579] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Spin trapping has been commonly employed in the detection of superoxide radical anion in chemical and biological systems; hence, accurate interpretation of the hyperfine splitting constants (hfsc's) arising from the O(2)(*-) adducts (also referred to as hydroperoxyl (HO(2)(*)) radical adducts) of various nitrones is important. In this work, the nature of the relevant hfsc's was investigated by examining the effect of conformational changes in the hydroperoxyl moiety of the O(2)(*-) adducts of 5,5-dimethyl-1-pyrroline N-oxide (DMPO), 5-ethoxycarbonyl-5-methyl-1-pyrroline N-oxide (EMPO), 5-diethoxyphosphoryl-5-methyl-1-pyrroline N-oxide (DEPMPO), 5-carbamoyl-5-methyl-1-pyrroline N-oxide (AMPO), and 7-oxa-1-azaspiro[4.4]non-1-en-6-one N-oxide, (CPCOMPO) on the magnitude of a(N), a(beta-H), and a(gamma-H). Conformational change around the substituents and their effect on the hfsc's were also explored. Results indicate that a(beta-H) is most sensitive to conformational changes of the hydroperoxyl and substituent groups relative to hfsc's of other nuclei. The orbital overlap between the C-H sigma-orbital and the SOMO of the nitroxyl nitrogen plays a crucial factor in determining the magnitude of the a(beta-H). The hfsc values for the O(2)(*-) adducts were predicted with high accuracy by using a low-cost computational method at the PCM(water)/BHandHLYP/EPR-III//B3LYP/6-31G* level of theory without taking into account the explicit water interaction.
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Otani T, Tsubogo T, Furukawa N, Saito T, Uchida K, Iwama K, Kanai Y, Yajima H. Synthesis of new UV-B light absorbents: (Acetylphenyl)glycosides with antioxidant activities. Bioorg Med Chem Lett 2008; 18:3582-4. [DOI: 10.1016/j.bmcl.2008.05.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2008] [Revised: 04/17/2008] [Accepted: 05/01/2008] [Indexed: 10/22/2022]
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