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Baschieri A, Jin Z, Amorati R, Vasa K, Baroncelli A, Menichetti S, Viglianisi C. Kinetic study of the reaction of thiophene-tocopherols with peroxyl radicals enlightenings the role of O˙⋯S noncovalent interactions in H-atom transfer. Org Biomol Chem 2024; 22:5965-5976. [PMID: 38984438 DOI: 10.1039/d4ob00944d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/11/2024]
Abstract
Three new α-tocopherol thiophene derivatives were efficiently synthesized, characterized and used for the first time as chain-breaking antioxidants for the inhibition of the autoxidation of reference oxidizable substrates. The rate constant of the reaction with alkylperoxyl (ROO˙) radicals and the stoichiometry of radical trapping (n) for the thiophene-tocopherol compounds were determined by measuring the oxygen consumption during the autoxidation of styrene or isopropylbenzene, using a differential pressure transducer. The measurement of the reaction with ROO˙ radicals in an apolar solvent at 30 °C showed inhibition rate constants (kinh) in the order of 104 M-1 s-1. To rationalise the kinetic results, the effect of the thiophene ring on the H-atom donation by O-H groups of the functionalized tocopherols was investigated by theoretical calculations. The importance of noncovalent interactions (including an unusual O˙⋯S bond) for the stability of the conformers has been shown, and the O-H bond dissociation enthalpy (BDE(OH)) of these derivatives was determined. Finally, the photophysical properties of these new compounds were investigated to understand if the addition of thiophene groups changes the absorption or emission spectra of the tocopherol skeleton for their possible application as luminescent molecular probes.
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Affiliation(s)
- Andrea Baschieri
- Institute for Organic Synthesis and Photoreactivity (ISOF), National Research Council of Italy (CNR), Via P. Gobetti 101, I-40129 Bologna, Italy.
| | - Zongxin Jin
- Department of Chemistry "G. Ciamician", University of Bologna, Via P. Gobetti 85, 40129 Bologna, Italy
| | - Riccardo Amorati
- Department of Chemistry "G. Ciamician", University of Bologna, Via P. Gobetti 85, 40129 Bologna, Italy
| | - Kristian Vasa
- Department of Chemistry "Ugo Schiff" - DICUS, University of Florence, Via Della Lastruccia 3-13, I-50019 Sesto Fiorentino, Firenze, Italy.
| | - Allegra Baroncelli
- Department of Chemistry "Ugo Schiff" - DICUS, University of Florence, Via Della Lastruccia 3-13, I-50019 Sesto Fiorentino, Firenze, Italy.
| | - Stefano Menichetti
- Department of Chemistry "Ugo Schiff" - DICUS, University of Florence, Via Della Lastruccia 3-13, I-50019 Sesto Fiorentino, Firenze, Italy.
| | - Caterina Viglianisi
- Department of Chemistry "Ugo Schiff" - DICUS, University of Florence, Via Della Lastruccia 3-13, I-50019 Sesto Fiorentino, Firenze, Italy.
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Alsabil K, Viault G, Suor-Cherer S, Helesbeux JJ, Merza J, Dumontet V, Peña-Rodriguez LM, Richomme P, Séraphin D. Efficient ortho-formylation in vitamin E series, application to the semi-synthesis of natural 5- and 7-formyl-δ-tocotrienols revealing an unprecedented 5-bromo-7-formyl exchange. Tetrahedron 2017. [DOI: 10.1016/j.tet.2017.10.039] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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3
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Song S, Sun X, Li X, Yuan Y, Jiao N. Efficient and Practical Oxidative Bromination and Iodination of Arenes and Heteroarenes with DMSO and Hydrogen Halide: A Mild Protocol for Late-Stage Functionalization. Org Lett 2015; 17:2886-9. [DOI: 10.1021/acs.orglett.5b00932] [Citation(s) in RCA: 160] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Affiliation(s)
- Song Song
- State Key Laboratory of Natural and Biomimetic Drugs, Peking University, School
of Pharmaceutical Sciences, Peking University, Xue
Yuan Road 38, Beijing 100191, China
| | - Xiang Sun
- State Key Laboratory of Natural and Biomimetic Drugs, Peking University, School
of Pharmaceutical Sciences, Peking University, Xue
Yuan Road 38, Beijing 100191, China
| | - Xinwei Li
- State Key Laboratory of Natural and Biomimetic Drugs, Peking University, School
of Pharmaceutical Sciences, Peking University, Xue
Yuan Road 38, Beijing 100191, China
| | - Yizhi Yuan
- State Key Laboratory of Natural and Biomimetic Drugs, Peking University, School
of Pharmaceutical Sciences, Peking University, Xue
Yuan Road 38, Beijing 100191, China
| | - Ning Jiao
- State Key Laboratory of Natural and Biomimetic Drugs, Peking University, School
of Pharmaceutical Sciences, Peking University, Xue
Yuan Road 38, Beijing 100191, China
- State Key Laboratory of Organometallic
Chemistry, Chinese Academy of Sciences, Shanghai 200032, China
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Poon JF, Singh VP, Yan J, Engman L. Regenerable Antioxidants-Introduction of Chalcogen Substituents into Tocopherols. Chemistry 2014; 21:2447-57. [DOI: 10.1002/chem.201405895] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Indexed: 12/13/2022]
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Singh VP, Poon JF, Engman L. Catalytic Antioxidants: Regenerable Tellurium Analogues of Vitamin E. Org Lett 2013; 15:6274-7. [DOI: 10.1021/ol403131t] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Vijay P. Singh
- Uppsala University, Department of Chemistry − BMC, Box 576, SE-751 23 Uppsala, Sweden
| | - Jia-fei Poon
- Uppsala University, Department of Chemistry − BMC, Box 576, SE-751 23 Uppsala, Sweden
| | - Lars Engman
- Uppsala University, Department of Chemistry − BMC, Box 576, SE-751 23 Uppsala, Sweden
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Yushkova YV, Chernyak EI, Polienko YF, Gatilov YV, Morozov SV, Grigor’ev IA. Synthesis of spin-labeled amides of 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (trolox). Chem Nat Compd 2013. [DOI: 10.1007/s10600-013-0574-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Novel tocopherol derivatives. Part 32: On the bromination of pyrano[3,2-f]chromenes related to γ-tocopherol. Tetrahedron 2011; 67:6181-6185. [PMID: 22031788 PMCID: PMC3190837 DOI: 10.1016/j.tet.2011.06.070] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2011] [Revised: 06/14/2011] [Accepted: 06/21/2011] [Indexed: 11/23/2022]
Abstract
While bromination of γ-tocopherol (2) with elemental bromine affords 5-bromo-γ-tocopherol quantitatively (3), the analogous reaction of its truncated model compound, 2,2,7,8-tetramethylchromanol (2a) is known to be accompanied by side reactions and to produce hitherto unknown byproducts. These compounds originate from pyrano[3,2-f]chromene (6), a byproduct in the synthesis of model compound 2a, which affords bromochromene 7 as the major product. The reaction mechanism was shown to proceed via chromene 8 and its 1,2-dibromo addition compound 9, which eliminates HBr in an E1 process to finally afford 7. Analytical data including crystal structures of both 6 and 7 are reported.
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Böhmdorfer S, Patel A, Hofinger A, Netscher T, Gille L, Rosenau T. Bromination of Tocopherols: Oxidative Halogenations and Rearrangements. European J Org Chem 2011. [DOI: 10.1002/ejoc.201100153] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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