Ethylnitrilium ion can be generated by protonation of acetonitrile (when used as the LC-MS mobile phase) under the conditions of atmospheric pressure ionizations, including electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI) as well as atmospheric pressure photoionization (APPI). Ethylnitrilium ion (CH(3)-C≡N+H and its canonical form CH(3)-C+=NH) is shown to efficiently undergo the gas-phase Meerwein reaction with epoxides. This reaction proceeds by the initial formation of an oxonium ion followed by three-to-five-membered ring expansion via an intramolecular nucleophilic attack to yield the Meerwein reaction products. The density functional theory (DFT) calculations at the B3LYP/6-311+G(d,p) level show that the gas-phase Meerwein reaction is thermodynamically favorable. Collision-induced dissociation (CID) of the Meerwein reaction products yields the net oxygen-by-nitrogen replacement of epoxides with a characteristic mass shift of 1 Da, providing evidence for the cyclic nature of the gas-phase Meerwein reaction products. The gas-phase Meerwein reaction offers a novel and fast LC-MS approach for the direct analysis of epoxides that might be of genotoxic concern during drug development. Understanding and utilizing this unique gas-phase ion/molecule reaction, the sensitivity and selectivity for quantitation of epoxides can be enhanced.
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http://dx.doi.org/10.1016/j.jasms.2010.06.017 | DOI Listing |
Org Lett
January 2025
Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal 741246, India.
An electrochemical strategy for the regioselective construction of seleno-benzothiophenes/furans is reported through electrochemical selenocyclization, followed by Wagner-Meerwein rearrangement. This electro-oxidative tandem process operates under metal-free and external chemical oxidant-free conditions. Advantageously, unprotected homopropargyl alcohols were found to be compatible under the reaction conditions, releasing water and dihydrogen as the biproduct.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
November 2024
Fachbereich Chemie, Philipps-Universität Marburg, Hans-Meerwein-Straße 4, 35043, Marburg, Germany.
The isolation of thermally unstable and highly reactive organoiron(IV) complexes is a challenge for synthetic chemists. In particular, the number of examples where the C-based ligand is not part of the chelating ligand remains scarce. These compounds are of interest because they could pave the way to designing catalytic cycles of bond forming reactions proceeding via organoiron(IV) intermediates.
View Article and Find Full Text PDFChemistry
January 2025
Department of Chemistry, Philipps-University Marburg, Hans-Meerwein-Straße 4, 35043, Marburg, Germany.
A series of dibenzobismepinyl (CHBi) substituted transition metal complexes of the type [(CHBi)M(CO)(L)] (M=Mn, Co, Fe) was prepared in salt elimination reactions from a halobismepine and sodium metallates. Irradiation of these complexes with visible light has been investigated, aiming at the elimination of one carbonyl ligand and the concomitant coordination of the bismepine's olefin moiety to the transition metal center. The resulting complexes of the type [{κC,κBi-(CH)Bi}M(CO)(L)] (M=Co, Fe) have been isolated and fully characterized.
View Article and Find Full Text PDFJ Am Chem Soc
October 2024
Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstraße 5-13(D), München D-81377, Germany.
The cesium-poor alkali-metal suboxidometalates CsO ( = In, Sc) were prepared from the respective cesium-rich suboxidometalates CsO by thermolysis in a dynamic vacuum at temperatures below 150 °C. They crystallize in a new structure type, comprising isolated tetrahedral oxidometalate anions [O] immersed in a matrix of metallic cesium atoms. This structural separation into alternating ionic and metallic building units is typical for subvalent compounds.
View Article and Find Full Text PDFChemSusChem
October 2024
CAS Key Laboratory of Renewable Energy, Guangdong Provincial Key Laboratory of New and Renewable Energy Research and Development, Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou, 510640, PR China.
The selective activation of C=O bonds was the key challenge in the field of biomass utilization. Researchers worked on this purpose by developing high-active and high-selective catalysts. In this study, a Pd/α-MoC single-atom catalyst was synthesized and applied in selective hydrogenation of biomass-derived furfural with 96.
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