- Metal-free aerobic oxidative coupling of amines in dimethyl sulfoxide via a radical pathway
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Metal-free oxidative coupling of amines is achieved simply by heating their dimethyl sulfoxide (DMSO) solution under oxygen as oxidant without any other catalysts or additives, accompanied by the formation of an equimolar amount of dimethyl sulfone (DMSO2). EPR experiments indicate that the reaction proceeds via a radical pathway. DMSO may play a triple role as solvent, radical initiator and co-reductant.
- Lin, Mu,Wang, Zikuan,Fang, Huayi,Liu, Lianghui,Yin, Haolin,Yan, Chun-Hua,Fu, Xuefeng
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- Carbonylation Access to Phthalimides Using Self-Sufficient Directing Group and Nucleophile
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Herein we report a novel palladium-catalyzed oxidative carbonylation reaction for the synthesis of phthalimides with high atom- and step-economy. In our strategy, the imine and H2O, which are generated in situ from the condensation of aldehyde and amine, serve as self-sufficient directing group and nucleophile, respectively. This method provides rapid access to phthalimides starting from readily available materials in a one-pot manner. Various phthalimide derivatives are constructed efficiently, including medicinally and biologically active phthalimide-containing compounds.
- Ji, Fanghua,Li, Jianxiao,Li, Xianwei,Guo, Wei,Wu, Wanqing,Jiang, Huanfeng
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p. 104 - 112
(2018/02/19)
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- Unusually Reactive Cyclic Anhydride Expands the Scope of the Castagnoli-Cushman Reaction
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In the course of synthesizing and testing various "azole-including" cyclic anhydrides in the Castagnoli-Cushman reaction with imines, a remarkably reactive, pyrrole-based anhydride has been identified. It displayed a remarkably efficient reaction with N-alkyl and N-aryl imines, in particular, with "enolizable" α-C-H imines which typically fail to react with a majority of known cyclic anhydrides. The reactivity of this anhydride has been justified by an efficient resonance stabilization of its enol form. This finding expands the existing arsenal of highly reactive cyclic anhydrides and further confirms the importance of anhydride enolization for an efficient Castagnoli-Cushman reaction.
- Chizhova, Maria,Khoroshilova, Olesya,Dar'In, Dmitry,Krasavin, Mikhail
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p. 12722 - 12733
(2018/10/15)
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- An investigation of the effects of CeO2 crystal planes on the aerobic oxidative synthesis of imines from alcohols and amines
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We herein report the effects of CeO2 crystal planes on the oxidative coupling of alcohols and amines to form imines. CeO2 exhibits significant catalytic activity under mild reaction conditions (60 °C) during the synthesis of 13 different imines, giving >89% conversions and >90% selectivities. The crystal planes of CeO2 greatly affect the catalytic performance. Among the crystal planes investigated (the (110), (100) and (111) planes), the (110) plane shows the strongest redox ability and thus the best catalytic activity, generating a 97% yield of the imine at 60 °C in 2 h, because it contains the highest concentration of oxygen vacancies.
- Zhang, Zhixin,Wang, Yehong,Wang, Min,Lü, Jianmin,Li, Lihua,Zhang, Zhe,Li, Mingrun,Jiang, Jingyang,Wang, Feng
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p. 1623 - 1630
(2015/09/15)
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- General and selective reductive amination of carbonyl compounds using a core-shell structured Co3O4/NGr@C catalyst
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The application of heterogenized non-noble metal-based catalysts in selective catalytic hydrogenation processes is still challenging. In this respect, the preparation of a well-defined cobalt-based catalyst was investigated by immobilization of the corresponding cobalt(ii)-phenanthroline-chelate on Vulcan XC72R carbon powder. The formed core-shell structured cobalt/cobalt oxide nanocomposites are encapsulated by nitrogen-enriched graphene layers. This promising cheap heterogeneous catalyst allows for an efficient domino reductive amination of carbonyl compounds with nitroarenes. This journal is
- Stemmler, Tobias,Westerhaus, Felix A.,Surkus, Annette-Enrica,Pohl, Marga-Martina,Junge, Kathrin,Beller, Matthias
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p. 4535 - 4540
(2014/12/10)
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- Iron-catalyzed synthesis of secondary amines: On the way to green reductive aminations
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Amines represent important intermediates in chemical and biological processes. Herein, we describe the use of a nanostructured iron-based catalyst for the tandem reductive amination between nitroarenes and aldehydes using hydrogen as reductant. The nanostructured iron-catalyst is prepared by immobilization of an iron-phenanthroline complex onto a commercially available carbon support. In the reaction sequence a primary amine is formed in situ from the corresponding nitro compound. Reversible condensation with aldehydes forms the respective imines, which are finally reduced to the desired secondary amine. This synthesis of secondary amines is atom-economical and environmentally attractive using cheap and readily available organic compounds as starting materials.
- Stemmler, Tobias,Surkus, Annette-Enrika,Pohl, Marga-Martina,Junge, Kathrin,Beller, Matthias
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p. 3012 - 3016
(2015/09/28)
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- Coupling of two multistep catalytic cycles for the one-pot synthesis of propargylamines from alcohols and primary amines on a nanoparticulated gold catalyst
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A one-pot reaction was performed with a nanoparticulated gold catalyst. A secondary amine is formed through N-monoalkylation of a primary amine with an alcohol by a borrowing hydrogen methodology in a three-step reaction. The secondary amine formed enters into a second A3-coupling cycle to give propargylamines. The multistep reaction requires a gold species formed and stabilized on a ceria surface. Copyright
- Corma, Avelino,Navas, Javier,Sabater, Maria J.
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p. 14150 - 14156
(2013/01/15)
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- Synthesis of substituted 1,4,5,6-tetrahydrocyclopenta[ b ]pyrroles by platinum-cata yzed cascade cyclization/ring expansion of 2-alkynyl-1-azaspiro[2. 3]hexanes
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The reaction of 2-alkynyl-1-azaspiro[2.3]hexanes with a platinum catalyst is described. 1,4,5,6-Tetrahydrocyclopenta[b]pyrroles having a variety of substituents were conveniently synthesized via a cascade cyclization/ring- expansion process.
- Yoshida, Masahiro,Maeyama, Yohei,Al-Amin, Mohammad,Shishido, Kozo
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experimental part
p. 5813 - 5820
(2011/09/14)
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- Electrochemical oxidation of benzylic amines into the corresponding imines in the presence of catalytic amounts of KI
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Oxidation of various benzylic amines using an indirect electrochemical method was successfully carried out under very mild conditions to afford the corresponding imines in good yields. Our results show that, for this electrolytic system, the iodide ions play an important role as electron carriers. Copyright Taylor & Francis, Inc.
- Okimoto, Mitsuhiro,Takahashi, Yukio,Numata, Kaori,Nagata, Yuji,Sasaki, Gaku
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p. 1989 - 1995
(2007/10/03)
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- Phosphatase inhibitors. III. Benzylaminophosphonic acids as potent inhibitors of human prostatic acid phosphatase
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Further investigation of the structural requirements of a series of benzylphosphonic acid inhibitors of human prostatic acid phosphatase has led to the highly potent series of α-aminobenzylphosphonic acids. The α-benzylaminobenzylphosphonic acid, with an IC50 = 4 nM, exhibited a 3500-fold improvement in potency over the carbon analogue, α-phenylethyl. The enhanced potency may be due to a combination of four favorable interactions including those with the phosphate binding region, the presence the hydrophobic moieties of the benzylamino and phenylphosphonic acid, and a rigid conformer produced by an internal salt bridge between the phosphonate and the α-amino group. Replacement of the phosphonic acid moiety with a phosphinic or carboxylic acid as well as deletion of the benzyl substitution on the α-amino group led to great reductions in potency.
- Beers, Scott A.,Schwender, Charles F.,Loughney, Deborah A.,Malloy, Elizabeth,Demarest, Keith,Jordan, Jerold
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p. 1693 - 1701
(2007/10/03)
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