- Benzimidazole fragment containing Mn-complex catalyzed hydrosilylation of ketones and nitriles
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The synthesis of a new bidentate (NN)–Mn(I) complex is reported and its catalytic activity towards the reduction of ketones and nitriles is studied. On comparing the reactivity of various other Mn(I) complexes supported by benzimidazole ligand, it was observed that the Mn(I) complexes bearing 6-methylpyridine and benzimidazole fragments exhibited the highest catalytic activity towards monohydrosilylation of ketones and dihydrosilylation of nitriles. Using this protocol, a wide range of ketones were selectively reduced to the corresponding silyl ethers. In case of unsaturated ketones, the chemoselective reduction of carbonyl group over olefinic bonds was observed. Additionally, selective dihydrosilylation of several nitriles were also achieved using this complex. Mechanistic investigations with radical scavengers suggested the involvement of radical species during the catalytic reaction. Stoichiometric reaction of the Mn(I) complex with phenylsilane revealed the formation of a new Mn(I) complex.
- Ganguli, Kasturi,Mandal, Adarsha,Sarkar, Bidisha,Kundu, Sabuj
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supporting information
(2020/08/13)
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- Cobalt pincer complexes for catalytic reduction of nitriles to primary amines
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Various cobalt pincer type complexes 1-6 were applied for the catalytic hydrogenation of nitriles to amines. Among these, catalyst 4 is the most efficient, allowing the reduction of aromatic as well as aliphatic nitriles in moderate to excellent yields.
- Schneek?nig, Jacob,Tannert, Bianca,Hornke, Helen,Beller, Matthias,Junge, Kathrin
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p. 1779 - 1783
(2019/04/27)
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- Chemo-selective reduction of nitro and nitrile compounds using Ni nanoparticles immobilized on hyperbranched polymer-functionalized magnetic nanoparticles
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The nitro and nitrile groups in aromatic and aliphatic compounds containing various reducible substituents such as carboxylic acid, ketone, aldehyde and halogen are selectively reduced to the corresponding amines in water as a green solvent with excellent yields by employing NaBH4 in the presence of Fe3O4@PAMAM/Ni(0)-b-PEG nanocatalyst. The morphology and structural features of the catalyst were characterized using various microscopic and spectroscopic techniques. The designed catalyst system because of it being covered with hydrophilic polymers is soluble in a wide range of solvents (e.g. water and ethanol) and suitable for immobilizing and stabilizing Ni nanoparticles in aqueous mediums. In addition, the catalyst can be easily recovered from a reaction mixture by applying an external magnetic field and can be reused up to six runs without significant loss of activity.
- Tabatabaei Rezaei, Seyed Jamal,Mashhadi Malekzadeh, Asemeh,Poulaei, Sima,Ramazani, Ali,Khorramabadi, Hossein
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- Versatile Dynamic Covalent Assemblies for Probing π-Stacking and Chirality Induction from Homotopic Faces
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Herein we report for the first time the use of dynamic covalent reactions (DCRs) for building a π-stacking model system and further quantifying its substituent effects (SEs), which remain a topic of debate despite the rich history of stacking. A general DCR between 10-methylacridinium ion and primary amines was discovered, in which π-stacking played a stabilizing role. Facile quantification of SEs with in situ competing π-stacking systems was next achieved in the form of amine exchange exhibiting structural diversity by simply varying components. The linear correlation with σm in Hammett plots indicates the dominance of purely electrostatic SEs, and the additivity of SEs is in line with the direct interaction model. With α-chiral amines π-stacking within the adduct enabled chirality transfer from homotopic faces. The strategy of dynamic covalent assembly should be appealing to future research of probing weak interactions and manipulating chirality.
- Ye, Hebo,Hai, Yu,Ren, Yulong,You, Lei
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supporting information
p. 3804 - 3809
(2017/03/27)
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- Stereoelectronic effects in the reaction of aromatic substrates catalysed by: Halomonas elongata transaminase and its mutants
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A transaminase from Halomonas elongata and four mutants generated by an in silico-based design were recombinantly produced in E. coli, purified and applied to the amination of mono-substituted aromatic carbonyl-derivatives. While benzaldehyde derivatives were excellent substrates, only NO2-acetophenones were transformed into the (S)-amine with a high enantioselectivity. The different behaviour of wild-type and mutated transaminases was assessed by in silico substrate binding mode studies.
- Contente, Martina Letizia,Planchestainer, Matteo,Molinari, Francesco,Paradisi, Francesca
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p. 9306 - 9311
(2016/10/13)
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- Homogeneous hydrogenation of nitriles catalyzed by molybdenum and tungsten amides
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Low-valent molybdenum and tungsten amides M(NO)(CO)(PNP) {M = Mo, 1a; W, 1b; PNP = N(CH2CH2PiPr2) 2} were found to be active catalysts for the hydrogenation of various nitriles to the corresponding imines, primary amines, and N-substituted imines with high selectivity for the latter type of product. A wide range of p-and m-substituted aromatic nitriles-p-methyl, p-methoxy, p-bromobenzonitriles; 3-trifluoromethylbenzonitrile, m-and p-disubstituted benzonitrile; the heterocyclic 2-thiophencarbonitrile; and the aliphatic nitriles cyclohexylcarbonitrile and benzylcyanide-could be hydrogenated at 140 °C and 60 bar H2 in THF with high yields. TOFs were found to be between 0.4 and 36 h-1.
- Chakraborty, Subrata,Berke, Heinz
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p. 2191 - 2194
(2014/07/21)
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- Tetracyclic benzimidazole derivatives and combinatorial libraries thereof
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The present invention relates to novel tetracyclic benzimidazole derivative compounds of the following formula: wherein R1to R10have the meanings described in here. The invention further relates to combinatorial libraries containing two or more such compounds, as well as methods of preparing tetracyclic benzimidazole derivative compounds.
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- Inhibitors of hepatitis C virus NS3 protease
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The present invention relates generally to a novel class of pyrimidinones of Formula (I): that are useful as serine protease inhibitors, and more particularly as Hepatitis C virus NS3 protease inhibitors. This invention also relates to pharmaceutical compositions comprising these compounds and methods of using the same.
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- 2-aminobenzoxazole derivatives and combinatorial libraries thereof
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The present invention relates to novel 2-aminobenzoxazole derivative compounds of the following formula: wherein R1 to R4 and Z have the meanings provided herein. The invention further relates to combinatorial libraries containing two or more such compounds, as well as methods of preparing 2-aminobenzoxazole derivative compounds.
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- 4-unsubstituted dihydroisoquinolinone derivatives and combinatorial libraries thereof
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The present invention relates to novel dihydroisoquinolinone (DHQ) derivative compounds of the following formula: wherein R1to R7, X, Y, Z, b, c and d have the meanings provided herein. The invention further relates to combinatorial libraries containing two or more such compounds, as well as methods of preparing DHQ derivative compounds.
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- Process for producing trifluoromethylbenzylamines
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The present invention relates to a process for producing a trifluoromethylbenzylamine represented by the general formula (1). This process includes the step of reducing an oxime represented by the general formula (2), where R1represents hydrogen atom, a halogen atom selected from the group consisting of fluorine, chlorine, bromine and iodine, or trifluoromethyl group, where R1is defined as above, and R2represents hydrogen atom, an alkyl group or an aralkyl group. With this process, the trifluoromethylbenzylamine can be produced with high selectivity.
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- Supported nickel-catalyzed hydrogenation of aromatic nitriles under low pressure conditions
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Hydrogenation of aromatic nitriles takes place under the mild conditions using supported nickel catalysts to afford amino-methyl-substituted aromatics in good yields.
- Takamizawa,Wakasa,Fuchikami
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p. 1623 - 1625
(2007/10/03)
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- Structural Effects on the Transition States of Imine-Forming Eliminations in N-Substituted O-(Arylsulfonyl)hydroxylamines
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A series of amines with various alkyl and aryl substituents at C-1 were converted to the corresponding N-(arylsulfonoxy)amines, which served as precursors for base-promoted, imine-forming elimination.By varying the bases used to promote the elimination and by varying the leaving groups attached to nitrogen, the Broensted parameters β and βlgCH3 were determined.These were used to locate the transition state on the More O'Ferrall-Jencks energy surface for elimination.Substituents were found to influence the structure of the activated complex markedly.Resonance effects were most important, while inductive effects had little influence .
- Hoffman, Robert V.,Shankweiler, Jean M.
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p. 4019 - 4022
(2007/10/02)
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- Inactivation of Leukocyte Elastase by Aryl Azolides and Sulfonate Salts. Structure-Activity Relationship Studies
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The inhibitory activity of a series of aryl azolides and sulfonate salts toward human leukocyte elastase is reported.Several of the compounds were found to be potent inhibitors of the enzyme.Active compounds were obtained only when the specificity group and the reactive moiety were separated by a two-carbon chain.The introduction of hydrophobic groups enhanced the inhibitory activity of these compounds, with the exception of the sulfonate salts.The nature of the leaving group had had a profound effect on inhibitory activity, with compounds 23 and 26 being the most active (kobsd/ = 11722 and 13500 M-1 s-1, respectively).
- Groutas, W. C.,Brubaker, M. J.,Zandler, M. E.,Mazo-Gray, V.,Rude, S. A.,et al.
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p. 1302 - 1305
(2007/10/02)
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- Benzylamines: Synthesis and evaluation of antimycobacterial properties
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The synthesis of benzylamines with various N-alkyl chains and substituents in the aromatic system as well as their evaluation on Mycobacterium tuberculosis H 37 Ra are described. The most active compounds in this test, N-methyl-3-chlorobenzylamine (MIC 10.2 μg/mL), N-methyl-3,5-dichlorobenzylamine (93, MIC 10.2 μg/mL), and N-butyl-3,5-difluorobenzylamine (MIC 6.4 μg/mL), also exhibited a marked inhibitory effect on Mycobacterium marinum and Mycobacterium lufu used for the determination of antileprotic properties. The combination of 93 with aminosalicylic acid, streptomycin, or dapsone exert marked supra-additive effects on M. tuberculosis H 37 Ra.
- Meindl,Von Angerer,Schonenberger,Ruckdeschel
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p. 1111 - 1118
(2007/10/02)
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