- Nickel-Catalyzed Inter- and Intramolecular Aryl Thioether Metathesis by Reversible Arylation
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A nickel-catalyzed aryl thioether metathesis has been developed to access high-value thioethers. 1,2-Bis(dicyclohexylphosphino)ethane (dcype) is essential to promote this highly functional-group-tolerant reaction. Furthermore, synthetically challenging macrocycles could be obtained in good yield in an unusual example of ring-closing metathesis that does not involve alkene bonds. In-depth organometallic studies support a reversible Ni0/NiII pathway to product formation. Overall, this work not only provides a more sustainable alternative to previous catalytic systems based on Pd, but also presents new applications and mechanistic information that are highly relevant to the further development and application of unusual single-bond metathesis reactions.
- Delcaillau, Tristan,Bismuto, Alessandro,Lian, Zhong,Morandi, Bill
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supporting information
p. 2110 - 2114
(2019/12/24)
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- Sulfonium salt type chloramine antibacterial agent and synthetic method thereof
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The invention belongs to the technical field of chemical synthesis and application of chloramine antibacterial agents, and provides a sulfonium salt type chloramine antibacterial agent and a syntheticmethod thereof. A preparation method of the antibacterial agent comprises the following steps: taking bromoalkyl 5,5-dimethylhydantoin and thioether as raw materials to prepare a sulfonium salt bromide chloramine precursor compound IV; reacting the precursor compound IV with t-butyl hypochlorite at normal temperature after ion exchange to obtain an antibacterial agent compound I. The antibacterial agent disclosed by the invention introduces a cationic structural unit-sulfonium salt group into a hydrophobic chain chloramine group, so that water solubility of the chloramine antibacterial agentis greatly improved and structure stability of the chloramine antibacterial agent is significantly enhanced. By using staphylococcus aureus as a model strain, the antibacterial test result shows thatthe bactericidal activity of the prepared sulfonium salt type chloramine compound is better than that of a mono-quaternary ammonium salt type chloramine compound.
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Paragraph 0029; 0030
(2018/11/22)
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- A model for the cobalamin-dependent methionine synthase
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The acid-catalyzed transfer of a Me group from N,N-dimethylaniline (6) to vitamin-B12-derived Co1 complexes 2a,b was realized (Scheme 3). Hexane- 1-thiol (8) was methylated by the methylcobalt complexes 4a,b in the presence of pyridine. Conditions for the complete cycle, i.e., Me transfer from 6 to 8 with Co1 complexes acting as a nucleophile and a nucleofuge have been established. The importance of Zn2+ as activating agent and of the basicity of tertiary amines for the Me transfer has been investigated.
- Wedemeyer-Exl, Christina,Darbre, Tamis,Keese, Reinhart
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p. 1173 - 1184
(2007/10/03)
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- New Oxyfunctionalization Capabilities for ω-Hydroxylases: Asymmetric Aliphatic Sulfoxidation and Branched Ether Demethylation
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Due to inherent difficulties in the chemical generation of aliphatic synthons, the stereo- and regioselective oxyfunctionalization of simple aliphatic substrates represents an area where chemical applications of biocatalysis would be particularly useful.The hydrocarbon monooxygenase from Pseudomonas oleovorans is a prototypical "ω-hydroxylase" known to carry out hydroxylation at the terminal methyl of alkanes as well as epoxidation of terminal olefins.It is now demonstrated that this enzyme system catalyzes stereoselective sulfoxidation of methyl thioether substrates, representing the first clear example of oxygenase-produced chiral aliphatic sulfoxides yet reported.In addition, it is shown that this enzyme system catalyzes oxygenative O-demethylation of branched alkyl methyl and branched vinyl methyl ethers to secondary alcohols and ketones, respectively.These findings establish new oxyfunctionalization capabilities, and thus a significantly expanded biotechnological potential, for the hydrocarbon monooxygenases.
- Katopodis, Andreas G.,Smith, Homer A.,May, Sheldon W.
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p. 897 - 899
(2007/10/02)
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- Dimethylcarbonat als Methylierungsmittel unter phasen-transfer-katalytischen Bedingungen
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Dimethyl carbonate (as well as diethyl, diallyl, dibenzyl carbonate and ethane-1,2-diyl carbonate) in the presence of potassium carbonate and 18-crown-6 (or Aliqual 336) is a versatile, cheap, and safer reagent for the methylation of a variety of organic substrates.
- Lissel, Manfred,Schmidt, Stefan,Neumann, Beate
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p. 382 - 383
(2007/10/02)
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