- Mono- And Dinuclear α-Diimine Nickel(II) and Palladium(II) Complexes in C-S Cross-Coupling
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The usefulness of transition metal catalytic systems in C-S cross-coupling reactions is significantly reduced by air and moisture sensitivity, as well as harsh reaction conditions. Herein, we report four highly air- and moisture-stable well-defined mononuclear and bridged dinuclear α-diimine Ni(II) and Pd(II) complexes for C-S cross-coupling. Various ligand frameworks, including acenaphthene- and iminopyridine-based ligands, were employed, and the resulting steric properties of the catalysts were evaluated and correlated with reaction outcomes. Under aerobic conditions and low temperatures, both Ni and Pd systems exhibited broader substrate scope and functional group tolerance than previously reported catalysts. Over 40 compounds were synthesized from thiols containing alkyl, benzyl, and heteroaryl groups. Also, pharmaceutically active heteroaryl moieties are incorporated from thiol and halide sources. Notably, the bridged dinuclear five-coordinate Ni complex has outperformed the remaining three mono four- or six-coordinate complexes by giving almost quantitative yields across a broad substrate scope.
- Talukder, Md Muktadir,Miller, Justin T.,Cue, John Michael O.,Udamulle, Chinthaka M.,Bhadran, Abhi,Biewer, Michael C.,Stefan, Mihaela C.
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- Transition metal-free coupling reactions of benzylic trimethylammonium salts with di(hetero)aryl disulfides and diselenides
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A new protocol was developed to synthesize (enantioenriched) thioethers and selenoethers from (chiral) benzylic trimethylammonium salts and di(hetero)aryl disulfides or diselenides. These syntheses were promoted by the presence of weak base and did not require the use of any transition metal, and resulted in the target products with good to excellent yields (72-94%). Using quaternary ammonium salts synthesized from enantiomerically enriched amines led to highly enantiopure benzylic thioethers and selenoethers (94-99% ee) with configurations reversed from those of their enantioenriched quaternary ammonium salts. This journal is
- Li, Fuhai,Wang, Dan,Chen, Hongyi,He, Ze,Zhou, Lihong,Zeng, Qingle
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p. 13029 - 13032
(2020/11/07)
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- Method for synthesizing (4-hydroxyphenyl) methyl benzyl sulfonium hexafluoroantimonate
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The invention relates to a method for synthesizing (4-hydroxyphenyl) methyl benzyl sulfonium hexafluoroantimonate. The method includes the following steps that in a solvent, 4-mercaptophenol or benzyl chloride or benzyl bromide serves as a raw material, and 4-(benzylthio) phenol is prepared under the action of triethylamine or potassium carbonate or sodium carbonate; in a toluene or cyclohexane or chloroform or dichloroethane solution, 4-(benzylthio) phenol and dimethyl sulfate or potassium iodide are methylated to obtain (4-hydroxyphenyl) methyl benzyl sulfonium sulfate or (4-hydroxyphenyl) methyl benzyl sulfonium iodate; in a methanol or alcohol or isopropanol solution, (4-hydroxyphenyl) methyl benzyl sulfonium sulfate and sodium hexafluoroantimonate are subjected to ion exchange to obtain the target product (4-hydroxyphenyl) methyl benzyl sulfonium hexafluoroantimonate. The method has the advantages that the raw materials are easy to obtain, the technology is simple, the prepared 4-(benzylthio) phenol is high in purity and does not need to be refined, and the requirement for large-scale industrial production of (4-hydroxyphenyl) methyl benzyl sulfonium hexafluoroantimonate can be met.
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Paragraph 0023; 0026; 0027; 0028
(2016/10/31)
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- Novel heterogeneous catalyst systems based on Pd(0) nanoparticles onto amine functionalized silica-cellulose substrates [Pd(0)-EDA/SCs]: Synthesis, characterization and catalytic activity toward C-C and C-S coupling reactions in water under limiting basic conditions
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Novel heterogeneous catalyst systems based on the immobilization of Pd(0) nanoparticles onto ethylene diamine functionalized silica-cellulose substrates [Pd(0)-EDA/SCs] are reported with a view to introduce new synthetic routes under base-free conditions. The base functionalized organic/inorganic hybrid provides specific basic sites for the reactions to occur under base-free or less basic conditions, and that too with excellent yields. Moreover, the basic nitrogen sites present on the substrate can effectively stabilize and enhance the activity of Pd(0) nanoparticles by preventing their agglomeration and controlling their size. All the catalysts were characterized by TGA and FTIR analysis and the most active catalyst, [Pd(0)-EDA/SC-2] was further characterized by SEM, TEM, HRTEM, EDX, CHN and XRD studies. Additionally, it is shown that the Pd(0)-EDA/SCs exhibits excellent activity under limiting basic conditions for the C-C and C-S coupling reactions employing water as the "Green solvent". Furthermore, the novel catalyst could be recovered in a facile manner from the reaction mixture and could be reused up to five times without significant loss of catalytic activity.
- Bhardwaj, Madhvi,Sahi, Seema,Mahajan, Hitesh,Paul, Satya,Clark, James. H.
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- A highly efficient Cu-catalyzed S-transfer reaction: From amine to sulfide
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A highly efficient Cu-catalyzed dual C-S bonds formation reaction, proceeding in alcohol and water under air, is reported, in which inodorous stable Na2S2O3 is used as a sulfurating reagent. This powerful strategy provides a practical and efficient approach to construct thioethers, using readily available aromatic amines and alkyl halides as starting materials. Sensitive and synthetic useful functional groups could be tolerated. Furthermore, pharmaceuticals, glucose, an amino acid, and a chiral ligand are successfully furnished by this late-stage sulfuration strategy.
- Li, Yiming,Pu, Jiahua,Jiang, Xuefeng
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supporting information
p. 2692 - 2695
(2014/06/09)
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- New 2-aryloxy-3-phenyl-propanoic acids as peroxisome proliferator-activated receptors α/γ dual agonists with improved potency and reduced adverse effects on skeletal muscle function
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The preparation of a new series of 2-aryloxy-3-phenyl-propanoic acids, resulting from the introduction of a linker into the diphenyl system of the previously reported PPARα/γ dual agonist 1, allowed the identification of new ligands with improved potency
- Fracchiolla, Giuseppe,Laghezza, Antonio,Piemontese, Luca,Tortorella, Paolo,Mazza, Fernando,Montanari, Roberta,Pochetti, Giorgio,Lavecchia, Antonio,Novellino, Ettore,Pierno, Sabata,Camerino, Diana Conte,Loiodice, Fulvio
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experimental part
p. 6382 - 6393
(2010/03/31)
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- Thioether substituted aryl carbonate protecting groups
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Embodiments of the invention include thioether substituted aryl carbonate protecting groups, and nucleoside monomers protected with thioether substituted aryl carbonate protecting groups. Aspects of the invention further included methods of synthesizing nucleic acids, e.g., oligonucleotides, using such protected nucleoside monomer monomers, as well as nucleic acids produced using methods of the invention and compositions thereof.
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- A simple one-pot synthesis of hydroxylated and carboxylated aryl alkyl sulfides from various bromobenzenes
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A simple one-pot synthesis of aryl alkyl sulfides from various bromobenzenes containing a hydroxy, hydroxymethyl, hydroxyethyl, and carboxylic acid group at -o, -m, and -p positions is reported here. The reaction proceeds through, in sequence, in situ pro
- Ko, Jaeyoung,Ham, Jungyeob,Yang, Inho,Chin, Jungwook,Nam, Sang-Jip,Kang, Heonjoong
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p. 7101 - 7106
(2007/10/03)
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- Structure-activity relationship studies on 1-[2-(4- phenylphenoxy)ethyl]pyrrolidine (SC-22716), a potent inhibitor of leukotriene A4 (LTA4) hydrolase
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Leukotriene B4 (LTB4) is a pro-inflammatory mediator that has been implicated in the pathogenesis of a number of diseases including inflammatory bowel disease (IBD) and psoriasis. Since the action of LTA4 hydrolase is the rate-limiting step for LTB4 production, this enzyme represents an attractive pharmacological target for the suppression of LTB4 production. From an in- house screening program, SC-22716 (1, 1-[2-(4- phenylphenoxy)ethyl]pyrrolidine) was identified as a potent inhibitor of LTA4 hydrolase. Structure-activity relationship (SAR) studies around this structural class resulted in the identification of a number of novel, potent inhibitors of LTA4 hydrolase, several of which demonstrated good oral activity in a mouse ex vivo whole blood assay.
- Penning, Thomas D.,Chandrakumar, Nizal S.,Chen, Barbara B.,Chen, Helen Y.,Desai, Bipin N.,Djuric, Stevan W.,Docter, Stephen H.,Gasiecki, Alan F.,Haack, Richard A.,Miyashiro, Julie M.,Russell, Mark A.,Yu, Stella S.,Corley, David G.,Durley, Richard C.,Kilpatrick, Brian F.,Parnas, Barry L.,Askonas, Leslie J.,Gierse, James K.,Harding, Elizabeth I.,Highkin, Maureen K.,Kachur, James F.,Kim, Suzanne H.,Krivi, Gwen G.,Villani-Price, Doreen,Pyla, E. Yvonne,Smith, Walter G.,Ghoreishi-Haack, Nayereh S.
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p. 721 - 735
(2007/10/03)
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- Mercapto phenolic and alkylthio phenolic antioxidants
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2-Mercapto phenol and/or 4-mercapto phenol are reacted with a compound selected from olefins, alcohols, and organic halides for example, styrene and isobutylene, to form (hydrocarbyl) thio phenolic antioxidants such as 2,6-di-tert. butyl-4-(tert.butylthio) phenol and 2,6-di(α-phenylethyl)-4-(α-phenylethylthio)phenol.
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