Facile N9-Alkylation of Xanthine Derivatives and Their Use as Precursors for <i>N</i>-Heterocyclic Carbene Complexes
The xanthine-derivatives 1,3,7-trimethylxanthine, 1,3-dimethyl-7-benzylxanthine and 1,3-dimethyl-7-(4-chlorobenzyl)xanthine are readily ethylated at N9 using the cheap alkylating agents ethyl tosylate or diethyl sulfate. The resulting xanthinium tosylate or ethyl sulfate salts can be converted into...
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MDPI AG
2021-06-01
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| Series: | Molecules |
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| Online Access: | https://www.mdpi.com/1420-3049/26/12/3705 |
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| author | Moloud Mokfi Jörg Rust Christian W. Lehmann Fabian Mohr |
| author_facet | Moloud Mokfi Jörg Rust Christian W. Lehmann Fabian Mohr |
| author_sort | Moloud Mokfi |
| collection | DOAJ |
| description | The xanthine-derivatives 1,3,7-trimethylxanthine, 1,3-dimethyl-7-benzylxanthine and 1,3-dimethyl-7-(4-chlorobenzyl)xanthine are readily ethylated at N9 using the cheap alkylating agents ethyl tosylate or diethyl sulfate. The resulting xanthinium tosylate or ethyl sulfate salts can be converted into the corresponding PF<sub>6</sub><sup>−</sup> and chloride salts. The reaction of these xanthinium salts with silver(I) oxide results in the formation of different silver(I) carbene-complexes. In the presence of ammonia, ammine complexes [Ag(NHC)(NH<sub>3</sub>)]PF<sub>6</sub> are formed, whilst with Et<sub>2</sub>NH, the bis(carbene) salts [Ag(NHC)<sub>2</sub>]PF<sub>6</sub> were isolated. Using the xanthinium chloride salts neutral silver(I) carbenes [Ag(NHC)Cl] were prepared. These silver complexes were used in a variety of transmetallation reactions to give the corresponding gold(I), ruthenium(II) as well as rhodium(I) and rhodium(III) complexes. The compounds were characterized by various spectroscopic methods as well as X-ray diffraction. |
| first_indexed | 2024-03-10T10:20:00Z |
| format | Article |
| id | doaj.art-e8efcbe085d34fdca7982bda2938bc05 |
| institution | Directory Open Access Journal |
| issn | 1420-3049 |
| language | English |
| last_indexed | 2024-03-10T10:20:00Z |
| publishDate | 2021-06-01 |
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| record_format | Article |
| series | Molecules |
| spelling | doaj.art-e8efcbe085d34fdca7982bda2938bc052023-11-22T00:32:45ZengMDPI AGMolecules1420-30492021-06-012612370510.3390/molecules26123705Facile N9-Alkylation of Xanthine Derivatives and Their Use as Precursors for <i>N</i>-Heterocyclic Carbene ComplexesMoloud Mokfi0Jörg Rust1Christian W. Lehmann2Fabian Mohr3Faculty of Mathematics and Natural Sciences, Inorganic Chemistry, Bergische University Wuppertal, 42119 Wuppertal, GermanyChemical Crystallography and Electron Microscopy Centre, Max Planck Institute for Coal Research, 45470 Mülheim an der Ruhr, GermanyChemical Crystallography and Electron Microscopy Centre, Max Planck Institute for Coal Research, 45470 Mülheim an der Ruhr, GermanyFaculty of Mathematics and Natural Sciences, Inorganic Chemistry, Bergische University Wuppertal, 42119 Wuppertal, GermanyThe xanthine-derivatives 1,3,7-trimethylxanthine, 1,3-dimethyl-7-benzylxanthine and 1,3-dimethyl-7-(4-chlorobenzyl)xanthine are readily ethylated at N9 using the cheap alkylating agents ethyl tosylate or diethyl sulfate. The resulting xanthinium tosylate or ethyl sulfate salts can be converted into the corresponding PF<sub>6</sub><sup>−</sup> and chloride salts. The reaction of these xanthinium salts with silver(I) oxide results in the formation of different silver(I) carbene-complexes. In the presence of ammonia, ammine complexes [Ag(NHC)(NH<sub>3</sub>)]PF<sub>6</sub> are formed, whilst with Et<sub>2</sub>NH, the bis(carbene) salts [Ag(NHC)<sub>2</sub>]PF<sub>6</sub> were isolated. Using the xanthinium chloride salts neutral silver(I) carbenes [Ag(NHC)Cl] were prepared. These silver complexes were used in a variety of transmetallation reactions to give the corresponding gold(I), ruthenium(II) as well as rhodium(I) and rhodium(III) complexes. The compounds were characterized by various spectroscopic methods as well as X-ray diffraction.https://www.mdpi.com/1420-3049/26/12/3705xanthines<i>N</i>-heterocyclic carbenesX-ray structures |
| spellingShingle | Moloud Mokfi Jörg Rust Christian W. Lehmann Fabian Mohr Facile N9-Alkylation of Xanthine Derivatives and Their Use as Precursors for <i>N</i>-Heterocyclic Carbene Complexes Molecules xanthines <i>N</i>-heterocyclic carbenes X-ray structures |
| title | Facile N9-Alkylation of Xanthine Derivatives and Their Use as Precursors for <i>N</i>-Heterocyclic Carbene Complexes |
| title_full | Facile N9-Alkylation of Xanthine Derivatives and Their Use as Precursors for <i>N</i>-Heterocyclic Carbene Complexes |
| title_fullStr | Facile N9-Alkylation of Xanthine Derivatives and Their Use as Precursors for <i>N</i>-Heterocyclic Carbene Complexes |
| title_full_unstemmed | Facile N9-Alkylation of Xanthine Derivatives and Their Use as Precursors for <i>N</i>-Heterocyclic Carbene Complexes |
| title_short | Facile N9-Alkylation of Xanthine Derivatives and Their Use as Precursors for <i>N</i>-Heterocyclic Carbene Complexes |
| title_sort | facile n9 alkylation of xanthine derivatives and their use as precursors for i n i heterocyclic carbene complexes |
| topic | xanthines <i>N</i>-heterocyclic carbenes X-ray structures |
| url | https://www.mdpi.com/1420-3049/26/12/3705 |
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