- Photoredox-Catalyzed Synthesis of α-Amino Acid Amides by Imine Carbamoylation
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An operationally simple protocol for the photocatalytic carbamoylation of imines is reported. Easily available, bench-stable 4-amido Hantzsch ester derivatives serve as precursors to carbamoyl radicals that undergo rapid addition to N-aryl imines. The reaction proceeds under blue light irradiation in the presence of the photocatalyst 3DPAFIPN and Br?nsted/Lewis acid additives. Mechanistic studies indicated a photoredox mechanism that involves carbamoyl radicals.
- Cardinale, Luana,Schmotz, Mattis-Ole W. S.,Konev, Mikhail O.,Jacobi von Wangelin, Axel
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supporting information
p. 506 - 510
(2022/01/20)
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- Ionic-Liquid-Catalyzed Synthesis of Imines, Benzimidazoles, Benzothiazoles, Quinoxalines and Quinolines through C?N, C?S, and C?C Bond Formation
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We report the tetramethyl ammonium hydroxide catalyzed oxidative coupling of amines and alcohols for the synthesis of imines under metal-free conditions by utilizing oxygen from air as the terminal oxidant. Under the same conditions, with ortho-phenylene diamines and 2-aminobenzenethiols the corresponding benzimidazoles and benzothiazoles were obtained. Quinoxalines were obtained from ortho-phenylene diamines and 1-phenylethane-1,2-diol, the conditions were then extended to the synthesis of quinoline building blocks by reaction of 2-amino benzyl alcohols either with 1-phenylethan-1-ol or acetophenone derivatives. The formation of C?N, C?S and C?C bonds was achieved under metal-free conditions. A broad range of amines (aromatic, aliphatic, cyclic and heteroaromatic) as well as benzylic alcohols including heteroaryl alcohols reacted smoothly and provided the desired products. The mild reaction conditions, commercially available catalyst, metal-free, good functional-group tolerance, broad range of products (imines, benzimidazoles, benzothiazoles, quinoxalines and quinolines) and applicability at gram scale reactions are the advantages of the present strategy.
- Adimurthy, Subbarayappa,Badhani, Gaurav,Joshi, Abhisek
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p. 6705 - 6716
(2021/12/31)
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- Azetidinimines as a novel series of non-covalent broad-spectrum inhibitors of β-lactamases with submicromolar activities against carbapenemases KPC-2 (class A), NDM-1 (class B) and OXA-48 (class D)
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The occurrence of resistances in Gram negative bacteria is steadily increasing to reach extremely worrying levels and one of the main causes of resistance is the massive spread of very efficient β-lactamases which render most β-lactam antibiotics useless. Herein, we report the development of a series of imino-analogues of β-lactams (namely azetidinimines) as efficient non-covalent inhibitors of β-lactamases. Despite the structural and mechanistic differences between serine-β-lactamases KPC-2 and OXA-48 and metallo-β-lactamase NDM-1, all three enzymes can be inhibited at a submicromolar level by compound 7dfm, which can also repotentiate imipenem against a resistant strain of Escherichia coli expressing NDM-1. We show that 7dfm can efficiently inhibit not only the three main clinically-relevant carbapenemases of Ambler classes A (KPC-2), B (NDM-1) and D (OXA-48) with Ki's below 0.3 μM, but also the cephalosporinase CMY-2 (class C, 86% inhibition at 10 μM). Our results pave the way for the development of a new structurally original family of non-covalent broad-spectrum inhibitors of β-lactamases.
- Romero, Eugénie,Oueslati, Saoussen,Benchekroun, Mohamed,D'Hollander, Agathe C.A.,Ventre, Sandrine,Vijayakumar, Kamsana,Minard, Corinne,Exilie, Cynthia,Tlili, Linda,Retailleau, Pascal,Zavala, Agustin,Elisée, Eddy,Selwa, Edithe,Nguyen, Laetitia A.,Pruvost, Alain,Naas, Thierry,Iorga, Bogdan I.,Dodd, Robert H.,Cariou, Kevin
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supporting information
(2021/04/19)
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- Metal-free regioselective C-H amination for the synthesis of pyrazole-containing 2H-indazoles
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A general and practical regioselective approach for the C-H amination of 2H-indazoles under transition-metal-free conditions was developed. A series of substrates were tested showing eminent functional group tolerance and affording the C-N functionalization products in good to excellent yields. Mechanism studies revealed that a radical process was involved in this transformation.
- Wang, Kai,Wei, Tingting,Zhang, Yujia,Hou, Jiahao,Bai, Renren,Xie, Yuanyuan
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p. 1787 - 1794
(2021/03/14)
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- Retraction: Harnessing Thiol as a Benzyl Reagent for Photocatalytic Reductive Benzylation of Imines (Organic Letters DOI: 10.1021/2Facs.orglett.0c00065)
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The authors retract this article after finding in subsequent studies that the quality of the purchased catalysts has a notable impact on the reproducibility of the results. Accordingly, the authors note that additional work is necessary to understand the
- Zhang, Jinghui,Zhang, Muliang
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supporting information
p. 2112 - 2112
(2020/02/15)
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- Metal-Free Ring Opening Cyclization of Cyclopropane Carbaldehydes and N-Benzyl Anilines: An Eco-Friendly Access to Functionalized Benzo[b]azepine Derivatives
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Herein, we report a p-toluenesulfonic acid (PTSA) initiated mild and user-friendly ring opening/domino ring opening cyclization reaction (depends on substituent present in N-benzyl aniline) of cyclopropane carbaldehyde and N-benzyl aniline towards the formation of substituted 4-amino butanal/2,3-dihydro-1H-benzo[b]azepine. The product dihydro-1H-benzo[b]azepine was also converted into the corresponding tetrahydro-1H-benzo[b]azepine. (Figure presented.).
- Dey, Raghunath,Banerjee, Prabal
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supporting information
p. 2849 - 2854
(2019/04/26)
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- Mild and efficient synthesis of secondary aromatic amines by one-pot stepwise reductive amination of arylaldehydes with nitroarenes promoted by reusable nickel nanoparticles
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The one-pot stepwise reductive amination of arylaldehydes with nitroarenes is described, using reusable nickel nanoparticles (Ni-pol) as catalyst and NaBH4 as mild, inexpensive, and safe reducing agent. The proposed catalytic system holds several advantages such as the use of a non-precious and earth-abundant metal, the facile separation of the catalyst from the reaction mixture by centrifugation, excellent stability towards air and moisture, very mild reaction conditions, good recyclability, broad substrate scope with good to excellent yields, and easy scalability (up to 1.0 g). FESEM analyses indicate that the active species are cubic nanocrystals of Ni in the average cross section value of 35 nm with a quite narrow (25–45 nm) and monomodal distribution, which becomes bimodal with the recycling reactions but without agglomeration.
- Fiore, Ambra Maria,Romanazzi, Giuseppe,Dell'Anna, Maria Michela,Latronico, Mario,Leonelli, Cristina,Mali, Matilda,Rizzuti, Antonino,Mastrorilli, Piero
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- Unsymmetrical indazolyl-pyridinyl-triazole ligand-promoted highly active iridium complexes supported on hydrotalcite and its catalytic application in water
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Herein, an indazolyl-pyridinyl-triazole ligand was synthesized and its iridium complex supported on hydrotalcite was characterized via X-ray power diffraction (XRD), X-ray photoelectron spectroscopy (XPS), energy dispersive X-ray (EDX) spectroscopy and transmission electron microscopy (TEM). This new heterogeneous catalyst bearing the unsymmetrical indazolyl-pyridinyl-triazole ligand exhibits high catalytic activity in water. Both functionalized amines and imines were obtained from the challenging selective reaction of benzylamines with arylamines through transfer hydrogenation and dehydrogenation under clean conditions. In particular, it was observed that this catalyst system showed good recovery performance in water. Mechanistic studies showed that this transformation occurs via amine dehydrogenation, hydrolysis and condensation processes. The direct capture of the reaction intermediate provides sufficient proof for this process.
- Ge, Chenyang,Sang, Xinxin,Yao, Wei,Zhang, Liang,Wang, Dawei
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supporting information
p. 1805 - 1812
(2018/04/30)
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- Manganese-Catalyzed and Base-Switchable Synthesis of Amines or Imines via Borrowing Hydrogen or Dehydrogenative Condensation
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The use of earth-abundant transition metals as a noble metal replacement in catalysis is especially interesting if different catalytic reactivity is observed. We report, here, on the selective manganese-catalyzed base-switchable synthesis of N-alkylated amines or imines. In both reactions, borrowing hydrogen/hydrogen autotransfer (N-alkyl amine formation) or dehydrogenative condensation (imine formation), we start from the same amines and alcohols and use the same Mn precatalyst. The key is the presence of a potassium base to prefer N-alkylation and a sodium base to permit imine formation. Both bases react with the manganese hydride via deprotonation. The potassium manganate hydride reacts about 40 times faster with an imine to give the corresponding amine than the sodium manganate hydride. The selectivity seems unique for manganese complexes. We observe a broad scope with a complete product overlap, all amine alcohol combinations can be converted into an N-alkyl amine or an imine, and a good functional group tolerance.
- Fertig, Robin,Irrgang, Torsten,Freitag, Frederik,Zander, Judith,Kempe, Rhett
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p. 8525 - 8530
(2018/09/06)
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- Manganese catalyzed reductive amination of aldehydes using hydrogen as a reductant
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A one-pot two-step procedure was developed for the alkylation of amines via reductive amination of aldehydes using molecular dihydrogen as a reductant in the presence of a manganese pyridinyl-phosphine complex as a pre-catalyst. After the initial condensation step, the reduction of imines formed in situ is performed under mild conditions (50-100 °C) with 2 mol% of catalyst and 5 mol% of tBuOK under 50 bar of hydrogen. Excellent yields (>90%) were obtained for a large combination of aldehydes and amines (40 examples), including aliphatic aldehydes and amino-alcohols.
- Wei, Duo,Bruneau-Voisine, Antoine,Valyaev, Dmitry A.,Lugan, No?l,Sortais, Jean-Baptiste
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supporting information
p. 4302 - 4305
(2018/05/03)
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- Cross-dehydrogenative coupling strategy for phosphonation and cyanation of secondary N-alkyl anilines by employing 2,3-dichloro-5,6-dicyanobenzoquinone
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The cross-dehydrogenative coupling strategy for metal-free phosphonation and cyanation of secondary N-alkyl anilines has been developed firstly under mild reaction conditions. Based on detailed optimization of reaction conditions, the substrate generality of N-alkyl anilines and various hydrogen phosphonates has been investigated, and a series of versatile α-aminophosphonates and α-aminonitriles were therefore furnished in good to excellent yields. A plausible collective reaction mechanism through dehydrogenation to imine formation, then to respective α-aminophosphonates and α-aminonitriles was proposed.
- Liu, Qing,Yu, Shuchen,Hu, Liangzhen,Hussain, Muhamad Ijaz,Zhang, Xiaohui,Xiong, Yan
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p. 7209 - 7217
(2018/11/10)
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- Lanthanides Mediated Oxidative Cross Coupling of Benzylalcohol and Various Amines to Form Corresponding Imines
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Herein, a new and efficient approach towards the oxidative cross-coupling of benzylalcohol and various aromatic amines to form corresponding imines with high degree conversion (>80 %) and chemo-selectivity using lanthanide salts as pre-catalysts is presented. The catalyzed oxidative cross-coupling reaction using La(NO3)3·6H2O as pre-catalyst displayed a broad substrate scope. The reaction afforded various substituted imines from the reaction of benzylalcohol with ample variety of amines in good yields.
- Bhattacharjee, Jayeeta,Sachdeva, Mitali,Panda, Tarun K.
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supporting information
p. 937 - 940
(2016/09/03)
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- Imine compound preparation method
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The invention relates to an imine compound preparation method. The preparation method comprises that benzyl alcohol or its derivative and an amine compound as reaction substrates undergo an oxidative condensation reaction in the presence of a catalyst to produce the imine compound. The imine compound preparation method utilizes a metal oxide as a catalyst and comprises that benzyl alcohol or its derivative, an amine compound and the metal oxide are mixed, the mixture is put into a pressure container, the pressure container is sealed, the mixture undergoes a stirring reaction at a temperature of 30-150 DEG C for 1-24h and the reaction product is separated so that the imine compound is obtained. The preparation method has the advantages of easy separation of the product and the catalyst, recycle of the catalyst, simple and easy reaction processes and the highest imine compound yield of 99%.
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Paragraph 0065; 0066
(2017/03/08)
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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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- Bifunctional iridium-(2-aminoterephthalate)-Zr-MOF chemoselective catalyst for the synthesis of secondary amines by one-pot three-step cascade reaction
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A simple and efficient method for the synthesis of N-alkyl amines via a cascade reaction (hydrogenation + reductive amination) using a new recyclable hybrid catalyst that combines the catalytic power of transition metal complexes with the architecture of metal organic frameworks (MOFs).
- Pintado-Sierra, Mercedes,Rasero-Almansa, Antonia M.,Corma, Avelino,Iglesias, Marta,Sanchez, Felix
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p. 137 - 145
(2013/03/28)
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- Multisite solid (NHC)NN-Ru-catalysts for cascade reactions: Synthesis of secondary amines from nitro compounds
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Supported ruthenium complexes based on electron-rich (NHC)NN-pincer-type ligands selectively catalyze the formation of substituted amines from nitroaromatics and carbonyl compounds through a series of consecutive steps which involves the reduction of nitro group to amine, the formation of an imine or iminium ion intermediate, followed by in situ reduction to an alkylated amine of higher order in a single operation. Solid complexes result active and recyclable catalysts and no deactivation was observed after repeated recycling.
- Del Pozo, Carolina,Corma, Avelino,Iglesias, Marta,Sanchez, Felix
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experimental part
p. 110 - 116
(2012/08/08)
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- Synthetic method for the preparation of 2-aminomethyl-1,3-diene derivatives through indium-mediated 1,3-butadien-2-ylation of imines
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An efficient method for the preparation of a variety of 2-aminomethyl-1,3-dienes was developed through the reaction of imines with organoindium reagent generated in situ from indium and 1,3-dibromo-2-butyne. Three-component reactions of aldehydes, amines,
- Seomoon, Dong,Jaemyung A.,Lee, Phil Ho
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supporting information; experimental part
p. 2401 - 2404
(2009/10/10)
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- Catalytic deprotonative functionalization of propargyl silyl ethers with imines
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A metal-free, catalytic C-H functionalization of propargyl silyl ethers with imines using the phosphazene base (t-Bu-P4 base) provides structurally defined multisubstituted pyrroles in modest to excellent yields under mild conditions. A one-pot, three-component reaction using silylated acetylenes, aldehydes, and imines is also presented.
- Naka, Hiroshi,Koseki, Daiki,Kondo, Yoshinori
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supporting information; experimental part
p. 1901 - 1906
(2009/08/07)
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- A facile, one-pot procedure for forming diarylimines from nitroarenes and benzaldehydes
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An intermolecular reductive Schiff base formation from nitroarenes and benzaldehydes to yield diarylimines is carried out in the presence of iron powder and dilute acid. This process is tolerant of an array of functional groups and often proceeds quantitatively with no need for purification. Georg Thieme Verlag Stuttgart.
- Korich, Andrew L.,Hughes, Thomas S.
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p. 2602 - 2604
(2008/02/13)
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- Kinetics and mechanism of the Pudovik reaction in the azomethine series: III. Acid-catalyzed hydrophosphorylation of imines
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A complex spectral (UV, IR, and 31P NMR), preparative, and kinetic investigation of the mechanism of the noncatalytic variant of the Pudovik reaction in the series of imines was carried out. The reaction proceeds through a four-center cyclic transition state. The transition state is highly labile, which determines its high sensitivity to the structure of the reagents, the nature of the solvent and catalyst, and some other factors. The necessary condition for the hydrophosphorylation of imines to occur is the participation of proton-donor reagents and acidic admixtures, specifically hydrolysis products of dialkyl hydrogen phosphites, such as monoalkyl dihydrogen phosphates and phosphorous acid, which act as acid catalysts. When the starting reagents are thoroughly purified and no such catalysts are present, the Pudovik reaction fails to occur in the imine series. Pleiades Publishing, Inc., 2006.
- Sobanov,Zolotukhin,Galkina,Galkin,Cherkasov
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p. 421 - 429
(2008/02/09)
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- Oxidative rearrangement of imines to formamides using sodium perborate
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Oxidation of C-aryl or alkyl-N-arylaldimines 6 or 20 by sodium perborate tetrahydrate (SPB) in trifluoroacetic acid solution gives rearranged N,N-disubstituted formamides 9 and 21. Yields are variable and solvent dependant with the best yields (50-60%) being obtained for electronically neutral C-aryl substituents or C-s-alkyl substituents. Product formation is rationalised in terms of an intermediate oxaziridine 5 that rearranges via acid catalysed O-N bond cleavage. An alternative C-O bond cleavage of these intermediates accounts for the formation of aldehydes, which are common by products. Rearrangement appears to be favoured by N-aryl substituents and by C-substituents that do not stabilise a developing positive charge on carbon. Further support for an oxaziridine intermediate 5 is provided by the observation that MCPBA oxidation of benzaldehyde phenylimine gives rearranged N,N-diphenylformamide. Under the conditions of the SPB oxidative rearrangements, oxaziridine formation may well occur by initial formation of trifluoroperacetic acid. Stereochemical aspects of this novel rearrangement of aldimines 1 → 2 have been investigated using trans- and cis-myrtanal 25 and 30. The observed epimerisation using die N-4-tolyl imine of trans-myrtanal 26 is believed to arise from equilibration of the precursor imine 26 with the tautomeric enamine 35b.
- Nongkunsarn, Pakawan,Ramsden, Christopher A.
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p. 3805 - 3830
(2007/10/03)
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