Synthesis and Trapping of the Elusive <i>Ortho</i>-Iminoquinone Methide Derived from α-Tocopheramine and Comparison to the Case of α-Tocopherol
Tocopheramines are a class of antioxidants which are distinguished from tocopherols (vitamin E) by the presence of an amino group instead of the phenolic hydroxyl group. α-Tocopheramine is intensively studied for biomedical applications but also as a stabilizer for synthetic and natural polymers, in...
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2025-08-01
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| author | Anjan Patel Thomas Rosenau |
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| description | Tocopheramines are a class of antioxidants which are distinguished from tocopherols (vitamin E) by the presence of an amino group instead of the phenolic hydroxyl group. α-Tocopheramine is intensively studied for biomedical applications but also as a stabilizer for synthetic and natural polymers, in particular for cellulose solutions and spinning dopes for cellulosic fibers. This study addresses a fundamental difference in the oxidation chemistry of α-tocopheramine and its tocopherol counterpart: while the formation of the ortho-quinone methide (o-QM) involving C-5a is one of the most fundamental reactions of α-tocopherol, the corresponding ortho-iminoquinone methide (o-IQM) derived from α-tocopheramine has been elusive so far. Synthesis of the transient intermediate succeeded initially via 5a-hydroxy-α-tocopheramine, and its occurrence was confirmed by dimerization to the corresponding spiro-dimer and by trapping with ethyl vinyl ether. Eventually, suitable oxidation conditions were found which allowed for the generation of the o-IQM directly from α-tocopheramine. The underlying oxidation chemistry of α-tocopherol and α-tocopheramine is concisely discussed. |
| format | Article |
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| institution | Kabale University |
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| language | English |
| publishDate | 2025-08-01 |
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| series | Molecules |
| spelling | doaj-art-1ceaf16c5454469f947addc223d7a5cf2025-08-20T03:36:31ZengMDPI AGMolecules1420-30492025-08-013015325710.3390/molecules30153257Synthesis and Trapping of the Elusive <i>Ortho</i>-Iminoquinone Methide Derived from α-Tocopheramine and Comparison to the Case of α-TocopherolAnjan Patel0Thomas Rosenau1Department of Natural Sciences and Sustainable Resources, Institute of Chemistry of Renewable Resources, BOKU University, Konrad-Lorenz-Straße 24, 3430 Tulln, AustriaDepartment of Natural Sciences and Sustainable Resources, Institute of Chemistry of Renewable Resources, BOKU University, Konrad-Lorenz-Straße 24, 3430 Tulln, AustriaTocopheramines are a class of antioxidants which are distinguished from tocopherols (vitamin E) by the presence of an amino group instead of the phenolic hydroxyl group. α-Tocopheramine is intensively studied for biomedical applications but also as a stabilizer for synthetic and natural polymers, in particular for cellulose solutions and spinning dopes for cellulosic fibers. This study addresses a fundamental difference in the oxidation chemistry of α-tocopheramine and its tocopherol counterpart: while the formation of the ortho-quinone methide (o-QM) involving C-5a is one of the most fundamental reactions of α-tocopherol, the corresponding ortho-iminoquinone methide (o-IQM) derived from α-tocopheramine has been elusive so far. Synthesis of the transient intermediate succeeded initially via 5a-hydroxy-α-tocopheramine, and its occurrence was confirmed by dimerization to the corresponding spiro-dimer and by trapping with ethyl vinyl ether. Eventually, suitable oxidation conditions were found which allowed for the generation of the o-IQM directly from α-tocopheramine. The underlying oxidation chemistry of α-tocopherol and α-tocopheramine is concisely discussed.https://www.mdpi.com/1420-3049/30/15/3257tocopheraminevitamin Eoxidation<i>ortho</i>-iminoquinone methidehetero-Diels–Alder reaction with inverse electron demandspiro-dimerization |
| spellingShingle | Anjan Patel Thomas Rosenau Synthesis and Trapping of the Elusive <i>Ortho</i>-Iminoquinone Methide Derived from α-Tocopheramine and Comparison to the Case of α-Tocopherol Molecules tocopheramine vitamin E oxidation <i>ortho</i>-iminoquinone methide hetero-Diels–Alder reaction with inverse electron demand spiro-dimerization |
| title | Synthesis and Trapping of the Elusive <i>Ortho</i>-Iminoquinone Methide Derived from α-Tocopheramine and Comparison to the Case of α-Tocopherol |
| title_full | Synthesis and Trapping of the Elusive <i>Ortho</i>-Iminoquinone Methide Derived from α-Tocopheramine and Comparison to the Case of α-Tocopherol |
| title_fullStr | Synthesis and Trapping of the Elusive <i>Ortho</i>-Iminoquinone Methide Derived from α-Tocopheramine and Comparison to the Case of α-Tocopherol |
| title_full_unstemmed | Synthesis and Trapping of the Elusive <i>Ortho</i>-Iminoquinone Methide Derived from α-Tocopheramine and Comparison to the Case of α-Tocopherol |
| title_short | Synthesis and Trapping of the Elusive <i>Ortho</i>-Iminoquinone Methide Derived from α-Tocopheramine and Comparison to the Case of α-Tocopherol |
| title_sort | synthesis and trapping of the elusive i ortho i iminoquinone methide derived from α tocopheramine and comparison to the case of α tocopherol |
| topic | tocopheramine vitamin E oxidation <i>ortho</i>-iminoquinone methide hetero-Diels–Alder reaction with inverse electron demand spiro-dimerization |
| url | https://www.mdpi.com/1420-3049/30/15/3257 |
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