An efficient synthesis of N-methylated amides using methanol in the presence of a ruthenium(II) catalyst is realized. Notably, applying this process, tandem C-methylation and N-methylation were achieved to synthesize α-methyl N-methylated amides. In addition, several kinetic studies and control experiments with the plausible intermediates were performed to understand this novel protocol. Furthermore, detailed computational studies were carried out to understand the mechanism of this transformation.
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An unusual semiquinone-mediated self-catalysis redox mechanism for the reaction between halohydroquinones and N-substituted hydroxamic acids.
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State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, The Chinese Academy of Sciences, Beijing, 100085, PR China; Sino-Danish College, University of Chinese Academy of Sciences, Beijing, 100049, PR China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, 100049, PR China; Linus Pauling Institute, Oregon State University, Corvallis, OR, 97331, USA. Electronic address:
We found recently that a C-C bonding phenyl-quinone product was produced with high yield (96 %) from the reaction between 2,5-dichloro-1,4-benzoquinone (DCBQ) and N-phenylbenzohydroxamic acid (N-PhBHA) via an unusual Claisen rearrangement mechanism, accompanied with the concurrent formation of the minor byproducts amide (N-phenylbenzamide, N-PhBA; only 2 % yield) and hydroxychloroquinone (2 % yield). Surprisingly, when DCBQ was replaced with its reduced form 2,5-dichloro-1,4-hydroquinone (DCHQ), no C-C bonding product was detected, whereas N-PhBA (83 % yield) and hydroxychloroquinone (80 % yield) became the predominant products, indicating a dramatic mechanistic shift. The ascorbate reduction experiment suggested that it was not DCHQ itself, but its corresponding semiquinone radical, that directly reacts with N-PhBHA.
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Institute of Inorganic Chemistry, Faculty of Chemistry, University of Vienna, Vienna, Austria.
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Department of Chemistry, University of California, Irvine, Irvine, California 92697, United States.
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- The lab successfully synthesized the peptide antibiotic clovibactin on a larger scale, allowing for better study of its amino acid components.
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Leibniz-Institut für Katalyse e.V., Albert-Einstein-Str. 29a, Rostock, D-18059, Germany.
Earth abundant metal-based heterogeneous catalysts with highly active and at the same time stable isolated metal sites constitute a key factor for the advancement of sustainable and cost-effective chemical synthesis. In particular, the development of more practical, and durable iron-based materials is of central interest for organic synthesis, especially for the preparation of chemical products related to life science applications. Here, we report the preparation of Fe-single atom catalysts (Fe-SACs) entrapped in N-doped mesoporous carbon support with unprecedented potential in the preparation of different kinds of amines, which represent privileged class of organic compounds and find increasing application in daily life.
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