- Photo-oxidation of L-Tyrosine, an Efficient 1,4-Chirality Transfer Reaction
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Dye-sensitized oxidation of L-tyrosine with Rose Bengal yielded the optically pure ketolactam (2) stereoselectively in one step.
- Endo, Katsuya,Seya, Kazuhiko,Hikino, Hiroshi
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- SALT EFFECTS ON THE KINETICS OF SUBSTITUTION OF THE PENTACYANO(PYRROLIDINE)FERRATE(II) ION
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Rate constants at 298.2 K for the release of pyrrolidine from pentacyano(pyrrolidine)ferrate(II) have been measured under pseudo-first-order conditions and the effect of inert inorganic and alkylammonium salts on the kinetics were investigated.The observe
- Pedrosa, Graciela C.,Hernandez, Norma L.,Katz, Nestor E.,Katz, Miguel
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- Mechanistic Investigations of the Catalytic Formation of Lactams from Amines and Water with Liberation of H2
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The mechanism of the unique lactam formation from amines and water with concomitant H2 liberation with no added oxidant, catalyzed by a well-defined acridine-based ruthenium pincer complex was investigated in detail by both experiment and DFT calculations. The results show that a dearomatized form of the initial complex is the active catalyst. Furthermore, reversible imine formation was shown to be part of the catalytic cycle. Water is not only the oxygen atom source but also acts as a cocatalyst for the H2 liberation, enabled by conformational flexibility of the acridine-based pincer ligand. (Figure Presented).
- Gellrich, Urs,Khusnutdinova, Julia R.,Leitus, Gregory M.,Milstein, David
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- Ion Confinement in the Collision Cell of a Multiquadrupole Mass Spectrometer: Access to Chemical Equilibrium and Determination of Kinetic and Thermodynamic Parameters of an Ion-Molecule Reaction
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Ions can be confined in an rf-only collision cell of a tandem quadrupole mass spectrometer so that ion-molecule reactions can be studied for variable interaction times (0.05-250 ms).The chemical system studied (ammonium ion, pyrrolidine, piperidine) involved the following reactions: proton exchange, formation of proton-bound dimers, and amine exchange between dimers.Chemical equilibrium could be reached for the exchange reactions.The equilibrium constants of these reactions, as well as the rate constants of the different reactions involved, were thus easily determined from the variation of relative abundance of reactant and product ions versus confinement time.
- Beaugrand, Claude,Jaouen, Daniel,Mestdagh, Helene,Rolando, Christian
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- PHOTOSENSITIZED SINGLE ELECTRON TRANSFER INITIATED N-DEBENZYLATION. A CONVENIENT AND MILD APPROACH
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A mild method of N-debenzylation via photosensitized single electron transfer (SET) using 9,10-dicyano anthracene (DCA) as electron acceptor in neutral medium is reported.
- Pandey, G.,Rani, K. Sudha
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- Novel β-galactosidase-specific O2-glycosylated diazeniumdiolate probes
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Three β-galactosidase-specific nitric-oxide-releasing diazeniumdiolate conjugated probes were prepared as a prelude to studies of new potential molecular MRI imaging agents. A glycosylated derivative, 2e, designed to be trafficked across cell membranes, was also prepared. We report, in detail, the synthesis and characterization of these probes. In addition, the release of diazeniumdiolate from the probes by β-galactosidase-catalyzed hydrolysis was used to estimate their efficacy as serum-stable, specific NO donors.
- Bedell, Barry,Bohle,Chua, Zhijie,Czerniewski, Alexander,Evans, Alan,Mzengeza, Shadreck
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- Surface ligands enhance the catalytic activity of supported Au nanoparticles for the aerobic α-oxidation of amines to amides
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The catalytic aerobic α-oxidation of amines in water is an atom economic and green alternative to current methods of amide synthesis. The reaction uses O2 as terminal oxidant, avoids hazardous reactants and gives water as the only byproduct. Here we report that the catalytic activity of silica-supported Au nanoparticles for the aerobic α-oxidation of amines can be improved by tethering pyridyl ligands to the support. In contrast, immobilization of thiol groups on the material gives activities comparable to Au supported on bare silica. Our studies indicate that the ligands affect the electronic properties of the Au nanoparticles and thereby determine their ability to activate O2 and mediate C-H cleavage in the amine substrate. The reaction likely proceeds via an Au catalyzed β-hydride elimination enabled by backdonation from electron-rich metal to the orbital. O2, which is also activated on electron-rich Au, acts as a scavenger to remove H from the metal surface and regenerate the active sites. The mechanistic understanding of the catalytic conversion led to a new approach for forming C-C bonds α to the N atoms of amines.
- Chatterjee, Puranjan,Kanbur, Uddhav,Manzano, J. Sebastián,Sadow, Aaron D.,Slowing, Igor I.,Wang, Hsin
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p. 1922 - 1933
(2022/04/07)
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- Ceria supported Ru0-Ruδ+ clusters as efficient catalyst for arenes hydrogenation
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Selective hydrogenation of aromatic amines, especially chemicals such as aniline and bis(4-aminocyclohexyl)methane for non-yellowing polyurethane, is of particular interests due to the extensive applications. To conquer the existing difficulties in selective hydrogenation, the Ru0-Ruδ+/CeO2 catalyst with solid frustrated Lewis pairs was developed for aromatic amines hydrogenation with excellent activity and selectivity under relative milder conditions. The morphology, electronic and chemical properties, especially the Ru0-Ruδ+ clusters and reducible ceria were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electronic microscopy (SEM), X-ray photoelectron spectroscopy (XPS), CO2 temperature programmed desorption (CO2-TPD), H2 temperature programmed reduction (H2-TPR), H2 diffuse reflectance Fourier transform infrared spectroscopy (H2-DRIFT), Raman, etc. The 2% Ru/CeO2 catalyst exhibited good conversion of 95% and selectivity greater than 99% toward cyclohexylamine. The volcano curve describing the activity and Ru state was found. Owning to the “acidic site isolation” by surrounding alkaline sites, condensation between the neighboring amine molecules could be effectively suppressed. The catalyst also showed good stability and applicability for other aromatic amines and heteroarenes containing different functional groups.
- Cao, Yanwei,Zheng, Huan,Zhu, Gangli,Wu, Haihong,He, Lin
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supporting information
p. 770 - 774
(2020/08/24)
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- PRODUCTION METHOD OF CYCLIC COMPOUND
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PROBLEM TO BE SOLVED: To provide an industrially simple production method of a cyclic compound. SOLUTION: A production method of a cyclic compound includes a step to obtain a reduced form (B) by reducing an unsaturated bond in a ring structure of an aromatic compound (A) by means of catalytic hydrogenation of the aromatic compound (A) or its salt using palladium carbon as a catalyst under a normal pressure, in which the aromatic compound (A) has one or more ring structures selected from a group consisting of a five membered-ring, a six membered-ring, and a condensed ring of the five membered-ring or the six membered-ring with another six membered-ring, a hetero atom can be included in the ring structure, and the aromatic compound (A) can have one or two side chains bonded to the ring structure and does not have any carbon-carbon triple bond in the side chain. SELECTED DRAWING: None COPYRIGHT: (C)2021,JPOandINPIT
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Paragraph 0057-0058; 0061-0063
(2021/05/05)
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- Zirconium-hydride-catalyzed site-selective hydroboration of amides for the synthesis of amines: Mechanism, scope, and application
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Developing mild and efficient catalytic methods for the selective synthesis of amines is a longstanding research objective. In this respect, catalytic deoxygenative amide reduction has proven to be promising but challenging, as this approach necessitates selective C–O bond cleavage. Herein, we report the selective hydroboration of primary, secondary, and tertiary amides at room temperature catalyzed by an earth-abundant-metal catalyst, Zr-H, for accessing diverse amines. Various readily reducible functional groups, such as esters, alkynes, and alkenes, were well tolerated. Furthermore, the methodology was extended to the synthesis of bio- and drug-derived amines. Detailed mechanistic studies revealed a reaction pathway entailing aldehyde and amido complex formation via an unusual C–N bond cleavage-reformation process, followed by C–O bond cleavage.
- Han, Bo,Jiao, Haijun,Wu, Lipeng,Zhang, Jiong
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p. 2059 - 2067
(2021/09/02)
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- A Lewis Base Nucleofugality Parameter, NFB, and Its Application in an Analysis of MIDA-Boronate Hydrolysis Kinetics
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The kinetics of quinuclidine displacement of BH3 from a wide range of Lewis base borane adducts have been measured. Parameterization of these rates has enabled the development of a nucleofugality scale (NFB), shown to quantify and predict the leaving group ability of a range of other Lewis bases. Additivity observed across a number of series R′3-nRnX (X = P, N; R′ = aryl, alkyl) has allowed the formulation of related substituent parameters (nfPB, nfAB), providing a means of calculating NFB values for a range of Lewis bases that extends far beyond those experimentally derived. The utility of the nucleofugality parameter is explored by the correlation of the substituent parameter nfPB with the hydrolyses rates of a series of alkyl and aryl MIDA boronates under neutral conditions. This has allowed the identification of MIDA boronates with heteroatoms proximal to the reacting center, showing unusual kinetic lability or stability to hydrolysis.
- García-Domínguez, Andrés,Gonzalez, Jorge A.,Leach, Andrew G.,Lloyd-Jones, Guy C.,Nichol, Gary S.,Taylor, Nicholas P.
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supporting information
(2022/01/04)
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- Highly economical and direct amination of sp3carbon using low-cost nickel pincer catalyst
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Developing more efficient routes to achieve C-N bond coupling is of great importance to industries ranging from products in pharmaceuticals and fertilizers to biomedical technologies and next-generation electroactive materials. Over the past decade, improvements in catalyst design have moved synthesis away from expensive metals to newer inexpensive C-N cross-coupling approaches via direct amine alkylation. For the first time, we report the use of an amide-based nickel pincer catalyst (1) for direct alkylation of amines via activation of sp3 C-H bonds. The reaction was accomplished using a 0.2 mol% catalyst and no additional activating agents other than the base. Upon optimization, it was determined that the ideal reaction conditions involved solvent dimethyl sulfoxide at 110 °C for 3 h. The catalyst demonstrated excellent reactivity in the formation of various imines, intramolecularly cyclized amines, and substituted amines with a turnover number (TON) as high as 183. Depending on the base used for the reaction and the starting amines, the catalyst demonstrated high selectivity towards the product formation. The exploration into the mechanism and kinetics of the reaction pathway suggested the C-H activation as the rate-limiting step, with the reaction second-order overall, holding first-order behavior towards the catalyst and toluene substrate.
- Brandt, Andrew,Rangumagar, Ambar B.,Szwedo, Peter,Wayland, Hunter A.,Parnell, Charlette M.,Munshi, Pradip,Ghosh, Anindya
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p. 1862 - 1874
(2021/01/20)
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- Method for protecting sulfonyl of deamination amine
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The invention discloses a method for removing sulfenyl protection of amine. The method comprises the following steps: dissolving N - sulfonyl-protected amine and a base in a reaction solvent, then adding diphenylphosphine to uniformly mix and maintain 90 °C. When TCL detection reaction is complete, a recrystallization method or an extraction separation method is adopted to obtain the target product. The method disclosed by the invention adopts diphenylphosphine as an extraction reagent, is good in reaction activity, high in selectivity and wide in application range, and can replace the use of a hazardous reagent under the basic heating condition. Prodrug research and development and industrial production are of great significance.
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Paragraph 0054-0056
(2021/11/03)
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- One-pot dual catalysis for the hydrogenation of heteroarenes and arenes
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A simple dinuclear monohydrido bridged ruthenium complex [{(η6-p-cymene)RuCl}2(μ-H-μ-Cl)] acts as an efficient and selective catalyst for the hydrogenation of various heteroarenes and arenes. The nature of the catalytically active species was investigated using a combination of techniques including in situ reaction monitoring, kinetic studies, quantitative poisoning experiments and electron microscopy, evidencing a dual reactivity. The results suggest that the hydrogenation of heteroarenes proceeds via molecular catalysis. In particular, monitoring the reaction progress by NMR spectroscopy indicates that [{(η6-p-cymene)RuCl}2(μ-H-μ-Cl)] is transformed into monomeric ruthenium intermediates, which upon subsequent activation of dihydrogen and hydride transfer accomplish the hydrogenation of heteroarenes under homogeneous conditions. In contrast, carbocyclic aryl motifs are hydrogenated via a heterogeneous pathway, by in situ generated ruthenium nanoparticles. Remarkably, these hydrogenation reactions can be performed using molecular hydrogen under solvent-free conditions or with 1,4-dioxane, and thus give access to a broad range of saturated heterocycles and carbocycles while generating no waste.
- Chatterjee, Basujit,Kalsi, Deepti,Kaithal, Akash,Bordet, Alexis,Leitner, Walter,Gunanathan, Chidambaram
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p. 5163 - 5170
(2020/09/07)
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- Catalytic reduction of aromatic ring in aqueous medium
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A method of reducing an aromatic ring under relatively mild condition using sub-nano particles of a transition metal supported on super paramagnetic iron oxide nanoparticles (SPIONs). The catalyst is efficient for catalyzing the reduction of both carbocyclic and heterocyclic compound. In compound comprising both carbocyclic and heterocyclic aromatic rings, the catalyst displays high regioselectivity for the heterocyclic ring.
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Page/Page column 10; 16
(2020/05/04)
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- Can Heteroarenes/Arenes Be Hydrogenated Over Catalytic Pd/C Under Ambient Conditions?
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Hydrogenation of over a dozen aromatic compounds, including both heteroarenes and arenes, over palladium on carbon (Pd/C, 1–100 molpercent) with H2-balloon pressure at room temperature is reported. Analyses using pyridine as a model substrate revealed that acetic acid was the best solvent, as using only 1 molpercent Pd/C provided piperidine quantitatively. Substrate scope analysis and density functional theory calculations indicated that reaction rates are highly dependent on frontier molecular orbital characteristics and the steric bulkiness of substituents. Moreover, the established method was used for the concise synthesis of the anti-Alzheimer drug donepezil (Aricept?).
- Tanaka, Nao,Usuki, Toyonobu
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p. 5514 - 5522
(2020/07/24)
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- Revisiting the role of acids and hydrogen bond acceptors in enamine formation
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A systematic investigation into the effects of acids and hydrogen bond acceptors on the reaction rates and equilibria of enamine formation is reported. Acids can accelerate the reaction but do not change the reaction equilibria. In comparison, hydrogen bond acceptors facilitate the enamine formation via their strong hydrogen bonding interaction with the water generated in the reaction.
- Hammond, Gerald B.,Lu, Zhichao,Xu, Bo
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supporting information
p. 6849 - 6852
(2020/10/02)
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- Coordination-Induced N-H Bond Weakening in a Molybdenum Pyrrolidine Complex: Isotopic Labeling Provides Insight into the Pathway for H2Evolution
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The synthesis and characterization of a cationic molybdenum pyrrolidine complex are described that exhibits significant coordination-induced N-H bond weakening. The N-H bond dissociation free energy (BDFE) of the coordinated pyrrolidine in [(PhTpy)(PPh2Me)2Mo(NH(pyrr))][BArF24] ([1-NH(pyrr)]+PhTpy = 4′-Ph-2,2′,6′,2″-terpyridine, NH(pyrr) = pyrrolidine, ArF24 = [C6H3-3,5-(CF3)2]4) was determined to be between 41 and 51 kcal mol-1 by thermochemical analysis and supported by a density functional theory (DFT) computed value of 48 kcal mol-1. The complex [1-NH(pyrr)]+ underwent proton-coupled electron transfer (PCET) to 2,4,6-tri-tert-butylphenoxyl radical, as well as spontaneous H2 evolution upon gentle heating to furnish the corresponding molybdenum pyrrolidide complex [(PhTpy)(PPh2Me)2Mo(N(pyrr))][BArF24] ([1-N(pyrr)]+). Thermolysis of the deuterated isotopologue [1-ND(pyrr)]+ still produced H2 with concomitant incorporation of the isotopic label into the pyrrolidide ligand in the product [(1-N(pyrr-dn)]+ (n = 0-2), consistent with an H2 evolution pathway involving intramolecular H-H bond formation followed by an intermolecular product-forming PCET step. These observations provide the context for understanding H2 evolution in the nonclassical ammine complex [(PhTpy)(PPh2Me)2Mo(NH3)][BArF24] ([1-NH3]+) and are supported by DFT-computed reaction thermochemistry. Overall, these studies offer rare insight into the H2 formation pathway in nonclassical amine complexes with N-H BDFEs below the thermodynamic threshold for H2 evolution and inform the development of well-defined, thermodynamically potent PCET reagents.
- Bezdek, Máté J.,Pelczer, István,Chirik, Paul J.
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supporting information
p. 3050 - 3059
(2020/09/02)
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- Synthesis of oxalamides by acceptorless dehydrogenative coupling of ethylene glycol and amines and the reverse hydrogenation catalyzed by ruthenium
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A sustainable, new synthesis of oxalamides, by acceptorless dehydrogenative coupling of ethylene glycol with amines, generating H2, homogeneously catalyzed by a ruthenium pincer complex, is presented. The reverse hydrogenation reaction is also accomplished using the same catalyst. A plausible reaction mechanism is proposed based on stoichiometric reactions, NMR studies, X-ray crystallography as well as observation of plausible intermediates.
- Ben-David, Yehoshoa,Diskin-Posner, Yael,Milstein, David,Zhou, Quan-Quan,Zou, You-Quan
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p. 7188 - 7193
(2020/07/23)
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- Discovery and characterization of an acridine radical photoreductant
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Photoinduced electron transfer (PET) is a phenomenon whereby the absorption of light by a chemical species provides an energetic driving force for an electron-transfer reaction1–4. This mechanism is relevant in many areas of chemistry, including the study of natural and artificial photosynthesis, photovoltaics and photosensitive materials. In recent years, research in the area of photoredox catalysis has enabled the use of PET for the catalytic generation of both neutral and charged organic free-radical species. These technologies have enabled previously inaccessible chemical transformations and have been widely used in both academic and industrial settings. Such reactions are often catalysed by visible-light-absorbing organic molecules or transition-metal complexes of ruthenium, iridium, chromium or copper5,6. Although various closed-shell organic molecules have been shown to behave as competent electron-transfer catalysts in photoredox reactions, there are only limited reports of PET reactions involving neutral organic radicals as excited-state donors or acceptors. This is unsurprising because the lifetimes of doublet excited states of neutral organic radicals are typically several orders of magnitude shorter than the singlet lifetimes of known transition-metal photoredox catalysts7–11. Here we document the discovery, characterization and reactivity of a neutral acridine radical with a maximum excited-state oxidation potential of ?3.36 volts versus a saturated calomel electrode, which is similarly reducing to elemental lithium, making this radical one of the most potent chemical reductants reported12. Spectroscopic, computational and chemical studies indicate that the formation of a twisted intramolecular charge-transfer species enables the population of higher-energy doublet excited states, leading to the observed potent photoreducing behaviour. We demonstrate that this catalytically generated PET catalyst facilitates several chemical reactions that typically require alkali metal reductants and can be used in other organic transformations that require dissolving metal reductants.
- MacKenzie, Ian A.,Wang, Leifeng,Onuska, Nicholas P. R.,Williams, Olivia F.,Begam, Khadiza,Moran, Andrew M.,Dunietz, Barry D.,Nicewicz, David A.
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- Basicities and Nucleophilicities of Pyrrolidines and Imidazolidinones Used as Organocatalysts
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The Br?nsted basicities pKaH (i.e., pKa of the conjugate acids) of 32 pyrrolidines and imidazolidinones, commonly used in organocatalytic reactions, have been determined photometrically in acetonitrile solution using CH acids as indicators. Most investigated pyrrolidines have basicities in the range 16 aH aH aH 12.6) and the 2-imidazoliummethyl-substituted pyrrolidine A21 (pKaH 11.1) are outside the typical range for pyrrolidines with basicities comparable to those of imidazolidinones. Kinetics of the reactions of these 32 organocatalysts with benzhydrylium ions (Ar2CH+) and structurally related quinone methides, common reference electrophiles for quantifying nucleophilic reactivities, have been measured photometrically. Most reactions followed second-order kinetics, first order in amine and first order in electrophile. More complex kinetics were observed for the reactions of imidazolidinones and several pyrrolidines carrying bulky 2-substituents, due to reversibility of the initial attack of the amines at the electrophiles followed by rate-determining deprotonation of the intermediate ammonium ions. In the presence of 2,4,6-collidine or 2,6-di-tert-butyl-4-methyl-pyridine, the deprotonation of the initial adducts became faster, which allowed the rate of the attack of the amines at the electrophiles to be determined. The resulting second-order rate constants k2 followed the correlation log?k2(20 °C) = sN(N + E), where electrophiles are characterized by one parameter (E) and nucleophiles are characterized by the two solvent-dependent parameters N and sN. In this way, the organocatalysts A1-A32 were integrated in our comprehensive nucleophilicity scale, which compares n-, -, and σ-nucleophiles. The nucleophilic reactivities of the title compounds correlate only poorly with their Br?nsted basicities.
- An, Feng,Maji, Biplab,Min, Elizabeth,Ofial, Armin R.,Mayr, Herbert
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supporting information
p. 1526 - 1547
(2020/02/04)
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- Organocatalytic Decarboxylation of Amino Acids as a Route to Bio-based Amines and Amides
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Amino acids obtained by fermentation or recovered from protein waste hydrolysates represent an excellent renewable resource for the production of bio-based chemicals. In an attempt to recycle both carbon and nitrogen, we report here on a chemocatalytic, metal-free approach for decarboxylation of amino acids, thereby providing a direct access to primary amines. In the presence of a carbonyl compound the amino acid is temporarily trapped into a Schiff base, from which the elimination of CO2 may proceed more easily. After evaluating different types of aldehydes and ketones on their activity at low catalyst loadings (≤5 mol%), isophorone was identified as powerful organocatalyst under mild conditions. After optimisation many amino acids with a neutral side chain were converted in 28–99 % yield in 2-propanol at 150 °C. When the reaction is performed in DMF, the amine is susceptible to N-formylation. This consecutive reaction is catalysed by the acidity of the amino acid reactant itself. In this way, many amino acids were efficiently transformed to the corresponding formamides in a one-pot catalytic system.
- Claes, Laurens,Janssen, Michiel,De Vos, Dirk E.
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p. 4297 - 4306
(2019/08/26)
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- Synthesis of: N -heterocycles from diamines via H2-driven NADPH recycling in the presence of O2
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Herein, we report an enzymatic cascade involving an oxidase, an imine reductase and a hydrogenase for the H2-driven synthesis of N-heterocycles. Variants of putrescine oxidase from Rhodococcus erythropolis with improved activity were identified. Substituted pyrrolidines and piperidines were obtained with up to 97% product formation in a one-pot reaction directly from the corresponding diamine substrates. The formation of up to 93% ee gave insights into the specificity and selectivity of the putrescine oxidase.
- Al-Shameri, Ammar,Borlinghaus, Niels,Weinmann, Leonie,Scheller, Philipp N.,Nestl, Bettina M.,Lauterbach, Lars
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p. 1396 - 1400
(2019/03/26)
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- Hydrogenation of N-Heteroarenes Using Rhodium Precatalysts: Reductive Elimination Leads to Formation of Multimetallic Clusters
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A rhodium-catalyzed method for the hydrogenation of N-heteroarenes is described. A diverse array of unsubstituted N-heteroarenes including pyridine, pyrrole, and pyrazine, traditionally challenging substrates for hydrogenation, were successfully hydrogenated using the organometallic precatalysts, [(η5-C5Me5)Rh(N-C)H] (N-C = 2-phenylpyridinyl (ppy) or benzo[h]quinolinyl (bq)). In addition, the hydrogenation of polyaromatic N-heteroarenes exhibited uncommon chemoselectivity. Studies into catalyst activation revealed that photochemical or thermal activation of [(η5-C5Me5)Rh(bq)H] induced C(sp2)-H reductive elimination and generated the bimetallic complex, [(η5-C5Me5)Rh(μ2,η2-bq)Rh(η5-C5Me5)H]. In the presence of H2, both of the [(η5-C5Me5)Rh(N-C)H] precursors and [(η5-C5Me5)Rh(μ2,η2-bq)Rh(η5-C5Me5)H] converted to a pentametallic rhodium hydride cluster, [(η5-C5Me5)4Rh5H7], the structure of which was established by NMR spectroscopy, X-ray diffraction, and neutron diffraction. Kinetic studies on pyridine hydrogenation were conducted with each of the isolated rhodium complexes to identify catalytically relevant species. The data are most consistent with hydrogenation catalysis prompted by an unobserved multimetallic cluster with formation of [(η5-C5Me5)4Rh5H7] serving as a deactivation pathway.
- Kim, Sangmin,Loose, Florian,Bezdek, Máté J.,Wang, Xiaoping,Chirik, Paul J.
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p. 17900 - 17908
(2019/11/19)
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- Catalytic Hydrogenation of Carboxamides with a Bifunctional Cp Ru Catalyst Bearing an Imidazol-2-ylidene with a Protic Aminoethyl Side Chain
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Synthesis of a Cp Ru complex bearing an NH 2 -functionalized N -heterocyclic carbene (C-N H) was achieved by treatment of CpRuBr(isoprene) with an equimolar amount of a silver complex, which was generated from Ag 2 O and 1-(2-aminoethyl)-3-methylimidazolium bromide, in CH 3 CN at room temperature. The new CpRuBr(C-N H) complex showed a higher catalytic performance than the related CpRuCl(P-N H) and CpRuCl(N-N H) complexes. In the reaction of N -arylcarboxamides, the amine products were obtained in satisfactory yields under mild temperature conditions.
- Ikariya, Takao,Kawano, Teruhiro,Kayaki, Yoshihito,Watari, Ryo
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p. 2542 - 2547
(2019/06/08)
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- One-pot synthesis of: N -methylpyrrolidine (NMPD) using Cu- and Ni-modified ZSM-5 as an efficient catalyst
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In this study, a green, efficient and low-cost process for the synthesis of N-methylpyrrolidine (NMPD) from 1,4-butanediol (BDO) and methylamine (MA) via a one-pot method was developed. Under the optimized reaction conditions, more than 90% yield of NMPD was achieved over a Cu and Ni modified ZSM-5 catalyst. The catalyst could be reused for several runs retaining a satisfactory catalytic performance, and the scale-up operation showed the potential of industrial application. Characterizations of BET, XPS, XRD, TEM, SEM, H2-TPR and NH3-TPD were conducted for the developed composite catalyst, which suggested that Cu2O and NiO were the main species on the support. Meanwhile, it was found that the H2 atmosphere, the high dispersion of metal oxides and the synergic effect between Cu and Ni species on ZSM-5 contributed to the excellent catalytic performance. Furthermore, a possible mechanism based on a borrowing-hydrogen process was also proposed.
- Long, Yan,Wang, Peixue,Fei, Yuqing,Zhou, Dawei,Liu, Shimin,Deng, Youquan
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p. 141 - 148
(2019/01/11)
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- B(C6F5)3-Catalyzed Deoxygenative Reduction of Amides to Amines with Ammonia Borane
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The first B(C6F5)3-catalyzed deoxygenative reduction of amides into the corresponding amines with readily accessible and stable ammonia borane (AB) as a reducing agent under mild reaction conditions is reported. This metal-free protocol provides facile access to a wide range of structurally diverse amine products in good to excellent yields, and various functional groups including those that are reduction-sensitive were well tolerated. This new method is also applicable to chiral amide substrates without erosion of the enantiomeric purity. The role of BF3 ? OEt2 co-catalyst in this reaction is to activate the amide carbonyl group via the in situ formation of an amide-boron adduct. (Figure presented.).
- Pan, Yixiao,Luo, Zhenli,Han, Jiahong,Xu, Xin,Chen, Changjun,Zhao, Haoqiang,Xu, Lijin,Fan, Qinghua,Xiao, Jianliang
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supporting information
p. 2301 - 2308
(2019/01/30)
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- Ru-Catalyzed Deoxygenative Transfer Hydrogenation of Amides to Amines with Formic Acid/Triethylamine
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A ruthenium(II)-catalyzed deoxygenative transfer hydrogenation of amides to amines using HCO2H/NEt3 as the reducing agent is reported for the first time. The catalyst system consisting of [Ru(2-methylallyl)2(COD)], 1,1,1-tris(diphenylphosphinomethyl) ethane (triphos) and Bis(trifluoromethane sulfonimide) (HNTf2) performed well for deoxygenative reduction of various secondary and tertiary amides into the corresponding amines in high yields with excellent selectivities, and exhibits high tolerance toward functional groups including those that are reduction-sensitive. The choice of hydrogen source and acid co-catalyst is critical for catalysis. Mechanistic studies suggest that the reductive amination of the in situ generated alcohol and amine via borrowing hydrogen is the dominant pathway. (Figure presented.).
- Pan, Yixiao,Luo, Zhenli,Xu, Xin,Zhao, Haoqiang,Han, Jiahong,Xu, Lijin,Fan, Qinghua,Xiao, Jianliang
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supporting information
p. 3800 - 3806
(2019/07/12)
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- A BEt3-Base catalyst for amide reduction with silane
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Reported herein is the development of a simple but practical catalytic system for the selective reduction of amides with hydrosilane or hydrosiloxane. Low-cost and readily available triethylborane (1.0 M in THF), in combination with a catalytic amount of an alkali metal base, was found to catalyze the reduction of all three amide classes (tertiary, secondary, and primary amides) to form amines under mild conditions. In addition, the selective transformation of secondary amides to aldimines and primary amides to nitriles can also be achieved by using a proper combination of BEt3 and base. The scope of these BEt3-base-catalyzed amide hydrosilylation reactions has been explored in depth. Preliminary results of mechanistic studies suggest a modified Piers' silane Si-H···B activation mode wherein the hydride abstraction by BEt3 is promoted by the coordination of an alkoxide or hydroxide anion to the Si center.
- Yao, Wubing,Fang, Huaquan,He, Qiaoxing,Peng, Dongjie,Liu, Guixia,Huang, Zheng
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- A BEt3-Base Catalyst for Amide Reduction with Silane
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Reported herein is the development of a simple but practical catalytic system for the selective reduction of amides with hydrosilane or hydrosiloxane. Low-cost and readily available triethylborane (1.0 M in THF), in combination with a catalytic amount of an alkali metal base, was found to catalyze the reduction of all three amide classes (tertiary, secondary, and primary amides) to form amines under mild conditions. In addition, the selective transformation of secondary amides to aldimines and primary amides to nitriles can also be achieved by using a proper combination of BEt3 and base. The scope of these BEt3-base-catalyzed amide hydrosilylation reactions has been explored in depth. Preliminary results of mechanistic studies suggest a modified Piers' silane Si-H···B activation mode wherein the hydride abstraction by BEt3 is promoted by the coordination of an alkoxide or hydroxide anion to the Si center.
- Yao, Wubing,Fang, Huaquan,He, Qiaoxing,Peng, Dongjie,Liu, Guixia,Huang, Zheng
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p. 6084 - 6093
(2019/05/24)
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- Formal Deoxygenative Hydrogenation of Lactams Using PNHP-Pincer Ruthenium Complexes under Nonacidic Conditions
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A formal deoxygenative hydrogenation of amides to amines with RuCl2(NHC)(PNHP) (NHC = 1,3-dimethylimizadol-2-ylidene, PNHP = bis(2-diphenylphosphinoethyl)amine) is described. Various secondary amides, especially NH-lactams, are reduced with H2 (3.0-5.0 MPa) to amines at a temperature range of 120-150 °C with 1.0-2.0 mol % of PNHP-Ru catalysts in the presence of Cs2CO3. This process consists of (1) deaminative hydrogenation of secondary amides to generate primary amines and alcohols, (2) dehydrogenative coupling of the transient amines with alcohols to generate imines, and (3) hydrogenation of imines to give the formally deoxygenated secondary amine products.
- Ogata, Osamu,Nara, Hideki,Matsumura, Kazuhiko,Kayaki, Yoshihito
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supporting information
p. 9954 - 9959
(2019/12/24)
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- Method for preparing tetrahydropyrrole by taking 1, 4-butanediol and ammonia as raw materials
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The invention discloses a method for preparing tetrahydropyrrole by taking 1, 4-butanediol and ammonia as raw materials. The method comprises the following steps: preparing a catalyst: dissolving copper nitrate, manganese nitrate and vanadium nitrate into water, dipping into a molecular sieve ZSM-5 for absorbing for 5h, and then activating at the temperature of 450-480 DEG C to obtain the Cu-Mn-V-ZSM-5 catalyst, wherein the total weight of the copper nitrate, the manganese nitrate and the vanadium nitrate is 0.5-2% of that of the molecular sieve; continuously introducing gas of the 1, 4-butanediol and the ammonia into a fixed bed reactor filled with the catalyst, and carrying out a reaction at the temperature of 300-360 DEG C, wherein the molar ratio of the 1, 4-butanediol to the ammonia is equal to 1 to (15-18), and the space velocity of the catalyst is 48kg/T*hr; carrying out water capture on the reaction product, recycling ammonia, and carrying out rectification on the crude productunder reduced pressure so as to obtain the tetrahydropyrrole product with content of greater than or equal to 99.5%, wherein the water content of the tetrahydropyrrole product is less than or equal to 0.02%. By adopting the technical scheme, the method provided by the invention is high in preparation technology and high in purity.
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Paragraph 0009
(2018/03/25)
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- Acceptorless Dehydrogenative Coupling Using Ammonia: Direct Synthesis of N-Heteroaromatics from Diols Catalyzed by Ruthenium
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The synthesis of N-heteroaromatic compounds via an acceptorless dehydrogenative coupling process involving direct use of ammonia as the nitrogen source was explored. We report the synthesis of pyrazine derivatives from 1,2-diols and the synthesis of N-substituted pyrroles by a multicomponent dehydrogenative coupling of 1,4-diols and primary alcohols with ammonia. The acridine-based Ru-pincer complex 1 is an effective catalyst for these transformations, in which the acridine backbone is converted to an anionic dearomatized PNP-pincer ligand framework.
- Daw, Prosenjit,Ben-David, Yehoshoa,Milstein, David
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supporting information
p. 11931 - 11934
(2018/09/27)
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- Polysilane-Immobilized Rh-Pt Bimetallic Nanoparticles as Powerful Arene Hydrogenation Catalysts: Synthesis, Reactions under Batch and Flow Conditions and Reaction Mechanism
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Hydrogenation of arenes is an important reaction not only for hydrogen storage and transport but also for the synthesis of functional molecules such as pharmaceuticals and biologically active compounds. Here, we describe the development of heterogeneous Rh-Pt bimetallic nanoparticle catalysts for the hydrogenation of arenes with inexpensive polysilane as support. The catalysts could be used in both batch and continuous-flow systems with high performance under mild conditions and showed wide substrate generality. In the continuous-flow system, the product could be obtained by simply passing the substrate and 1 atm H2 through a column packed with the catalyst. Remarkably, much higher catalytic performance was observed in the flow system than in the batch system, and extremely strong durability under continuous-flow conditions was demonstrated (>50 days continuous run; turnover number >3.4 × 105). Furthermore, details of the reaction mechanisms and the origin of different kinetics in batch and flow were studied, and the obtained knowledge was applied to develop completely selective arene hydrogenation of compounds containing two aromatic rings toward the synthesis of an active pharmaceutical ingredient.
- Miyamura, Hiroyuki,Suzuki, Aya,Yasukawa, Tomohiro,Kobayashi, Shu
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supporting information
p. 11325 - 11334
(2018/09/06)
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- An Efficient Ruthenium Catalyst Bearing Tetradentate Ligand for Hydrogenations of Carbon Dioxide
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A ruthenium complex with a tetradentate bipyridine ligand was proved to be a highly efficient catalyst for the conversions of CO2. Turnover numbers up to 300 000, 9800, and 2100 were achieved for the hydrogenations of CO2 to formamides, formamides to methanol and amines, and the direct hydrogenation of CO2 to methanol, respectively.
- Zhang, Feng-Hua,Liu, Chong,Li, Wei,Tian, Gui-Long,Xie, Jian-Hua,Zhou, Qi-Lin
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supporting information
p. 1000 - 1002
(2018/09/21)
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- Highly Selective, Efficient Deoxygenative Hydrogenation of Amides Catalyzed by a Manganese Pincer Complex via Metal-Ligand Cooperation
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Deoxygenative hydrogenation of amides to amines homogeneously catalyzed by a complex of an Earth-abundant metal is presented. This manganese-catalyzed reaction features high efficiency and selectivity. A plausible reaction mechanism, involving metal-ligand cooperation of the manganese pincer complex, is proposed based on NMR studies and relevant stoichiometric reactions.
- Zou, You-Quan,Chakraborty, Subrata,Nerush, Alexander,Oren, Dror,Diskin-Posner, Yael,Ben-David, Yehoshoa,Milstein, David
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p. 8014 - 8019
(2018/09/06)
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- Unique nanocages of 12CaO·7Al2O3 boost heterolytic hydrogen activation and selective hydrogenation of heteroarenes over ruthenium catalyst
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The chemoselective hydrogenation of heteroarenes is one of the most important synthetic reactions for the production of key intermediates in agrochemicals, pharmaceuticals and various fine chemicals. The development of new heterogeneous catalysts for the environmentally benign synthesis of heterocycle hydrogenated products is a fundamental objective for chemists. Here, we report that 12CaO·7Al2O3 with a unique sub-nanocage structure loaded with Ru nanoparticles exhibits higher activity, chemoselectivity and sustainability for the hydrogenation of heteroarenes in a solvent-free system than traditional oxide-supported metal catalysts. Conversion of >99% and a selectivity close to 99% were achieved for the hydrogenation of quinoline under mild conditions. This catalyst was also successfully applied to the hydrogenation of a variety of N- and O-heteroarenes with high yields. The superior catalytic performance can be attributed to a cooperative effect between the hydrogen-storage ability and large amount of strong basic sites on the surface of the support, which promotes heterolytic H2 cleavage and prevents poisoning of the metal surface caused by the adsorption of heteroarenes.
- Ye, Tian-Nan,Li, Jiang,Kitano, Masaaki,Hosono, Hideo
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p. 749 - 756
(2017/05/22)
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- Simple and efficient Fmoc removal in ionic liquid
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A mild method for an efficient removal of the fluorenylmethoxycarbonyl (Fmoc) group in ionic liquid was developed. The combination of a weak base such as triethylamine and [Bmim][BF4] makes the entire system more efficient for the cleavage at room temperature of various amines and amino acid methyl esters in short reaction times. The procedure works well even in the case of N-Fmoc amino acids bearing acid-sensitive protecting groups and of N-alkylated amino acid methyl esters. The solvent-free condition provides a complementary method for Fmoc deprotection in solution phase peptide synthesis and modern organic synthesis.
- Di Gioia,Costanzo,De Nino,Maiuolo,Nardi,Olivito,Procopio
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p. 36482 - 36491
(2017/08/02)
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- Putrescine Transaminases for the Synthesis of Saturated Nitrogen Heterocycles from Polyamines
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Putrescine transaminase (pATA; EC 2.6.1.82) catalyzes the transfer of an amino group from terminal diamine donor molecules to keto acid acceptors by using pyridoxal-5′-phosphate as a cofactor. The ygjG genes from Escherichia coli K12, Bacillus megaterium, and Bacillus mycoides were successfully cloned and expressed in E. coli BL21(DE3) cells. The three putrescine transaminases were all shown to prefer diaminoalkanes as substrates and thereby generated cyclic imines from the ω-amino aldehyde intermediates. The addition of a mild chemical reducing agent rapidly reduced the imine intermediate in situ to furnish a range of N-heterocycle products. We applied pATA in a biomimetic synthesis of 2,3-dihydro-1H-indolizinium-containing targets, notably the bioactive alkaloid ficuseptine.
- Slabu, Iustina,Galman, James L.,Weise, Nicholas J.,Lloyd, Richard C.,Turner, Nicholas J.
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p. 1038 - 1042
(2016/04/05)
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- The preparation obtained by homogeneous catalysis mellow amination method of the primary amine
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The invention relates to a method for producing primary amines comprising at least one functional group of formula (-CH2-NH2), by alcohol amination of educts which comprise at least one functional group of formula (-CH2-OH), using ammonia, and elimination of water. The homogeneously catalyzed alcohol amination is carried out in the presence of at least one complex catalyst which contains at least one element selected from the groups 8 and 9 of the periodic table and at least one phosphorus donor ligand of general formula (I).
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Paragraph 0207-0208; 0212
(2017/02/28)
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- Thermal stable copper metal organic framework material and preparation method and application thereof
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The invention discloses a thermal stable copper metal organic framework material and a preparation method and application thereof, and relates to the field of pyrrolidine catalysts. A catalyst is the thermal stable copper metal organic framework material, and the chemical formula of the thermal stable copper metal organic framework material is Cu(L)(NO3)2, wherein L represents a 2,3,5,6-tetrafluoro-1,4-bis(1,2,4-triazol-1-methyl)benzene ligand, and NO3 is nitrate anion. Cupric nitrate tetrahydrate and the organic ligand 2,3,5,6-tetrafluoro-1,4-bis(1,2,4-triazol-1-methyl)benzene are subjected to a hydrothermal reaction under an airtight condition, and the copper metal organic framework material with a two-dimensional layered structure is obtained. The synthetic method is high in yield and good in reproducibility; the obtained crystal is high in purity and thermal stability. The copper metal organic framework material has better catalytic activity on catalyzing of tetrahydrofuran gas phase amination, the conversion rate of tetrahydrofuran reaches 72%, and the selectivity of pyrrolidine reaches 90%.
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Paragraph 0037; 0038
(2017/04/06)
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- PdPb-Catalyzed decarboxylation of proline to pyrrolidine: Highly selective formation of a biobased amine in water
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Amino acids have huge potential as platform chemicals in the biobased industry. Pd-catalyzed decarboxylation is a very promising route for the valorization of these natural compounds derived from protein waste or fermentation. We report that the highly abundant and nonessential amino acid L-proline is very reactive in the Pd-catalyzed decarboxylation. Full conversions are obtained with Pd/C and different Pd/MeOx catalysts; this allowed the identification of the different side reactions and the mapping of the reaction network. Due to the high reactivity of pyrrolidine, the selectivity for pyrrolidine was initially low. By carefully modifying Pd/ZrO2 with Pb in a controlled mannervia two incipient wetness impregnation stepsthe selectivity increased remarkably. Finally, a thorough investigation of the reaction parameters resulted in an increased activity of this modified catalyst and an even further enhanced selectivity under a low H2 pressure of 4 bar at 235 °C in water. This results in a very selective and sustainable production route for the highly interesting pyrrolidine.
- Verduyckt, Jasper,Van Hoof, Maarten,De Schouwer, Free,Wolberg, Marike,Kurttepeli, Mert,Eloy, Pierre,Gaigneaux, Eric M.,Bals, Sara,Kirschhock, Christine E.A.,De Vos, Dirk E.
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p. 7303 - 7310
(2018/05/23)
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- Steric effects in the catalytic amination of γ-, δ-, and ε-glycols
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The amination of butane-1,4-diol, isomeric dipropylene glycols, and cyclohexane-1,4-diyldimethanol in the presence of nickel/copper/chromium catalysts has been studied. The effect of the initial glycol structure on the reaction selectivity has been estima
- Timofeev,Bazanov,Zubritskaya
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p. 1756 - 1761
(2017/02/19)
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- Production method of single nitrogenous heterocyclic ring-containing compound
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The invention discloses a production method of a single nitrogenous heterocyclic ring-containing compound. Lactone and fatty amine which are cheap and easy to obtain are used as raw materials for producing the single nitrogenous heterocyclic ring-containing compound; lactone and fatty amine are used for synthesis of amide, and hydrodeoxygenation is carried out in order to obtain the corresponding nitrogenous heterocyclic compound. The process has only two reaction steps, and has the advantages of low investment, high yield, simple separation for intermediate products, few by-products, and easy processing.
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Paragraph 0044; 0045
(2016/12/01)
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- Tailor-Made Ruthenium-Triphos Catalysts for the Selective Homogeneous Hydrogenation of Lactams
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The development of a tailored tridentate ligand enabled the synthesis of a molecular ruthenium-triphos catalyst, eliminating dimerization as the major deactivation pathway. The novel catalyst design showed strongly increased performance and facilitated the hydrogenation of highly challenging lactam substrates with unprecedented activity and selectivity. Bulky catalysts: A tailored sterically demanding tridentate ligand enabled the synthesis of a novel molecular ruthenium-triphos catalyst, which eliminates dimerization as the major deactivation pathway. The novel catalyst design showed increased performance and facilitated the hydrogenation of highly challenging lactam substrates with unprecedented activity and selectivity.
- Meuresch, Markus,Westhues, Stefan,Leitner, Walter,Klankermayer, Jürgen
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supporting information
p. 1392 - 1395
(2016/02/14)
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- Ligand, metal complex containing ligand, and reaction using metal complex containing ligand
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A hydrogen transfer reaction may be more efficiently promoted by using a metal complex represented by Formula (2): (wherein, R1 to R8 are the same or different, and each represents a hydrogen atom, a substituted or unsubstituted alkyl group or the like; or wherein; R1 and R2, R2 and R3, R3 and R4, R4 and R5, and R5 and R6 are respectively bonded to each other to form a bivalent hydrocarbon group; R9 are the same or different, and each represents an alkyl group or cycloalkyl group; M is ruthenium (Ru) or the like; X is a ligand; and n is 0, 1 or 2). More specifically, the metal complex enables a hydrogenation reaction of various substrates having a stable carbonyl group or the like to be advanced with a high yield under mild conditions.
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Page/Page column 46-50
(2016/10/31)
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- mellow amination by homogeneous catalysis of the method for the production of primary amines
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The invention relates to a method for producing primary amines by means of the alcohol amination of alcohols with ammonia, with water being eliminated. The method comprises the steps of: (a) a homogenously-catalysed reaction of a reaction mixture which contains at least one alcohol, ammonia, at least one non-polar solvent, and at least one catalyst containing at least one element selected from groups 8, 9 and 10 of the periodic table in the liquid phase, a product mixture (P) thus being obtained; (b) separating the phases of product mixture (P) which was obtained in step (a), if necessary after a reduction in temperature, a reduction in pressure and/or the addition of at least one polar solvent with a miscibility gap in relation to the non-polar solvent, and thus obtaining at least one polar product phase (A) and at least one non-polar phase (B) containing at least one portion of the catalyst that was introduced, with said non-polar phase (B) being separated off, (c) returning at least one portion of the non-polar phase (B) into the reaction in step (a), and (d) separating the amination product from the polar product phase (A). The non-polar solvent introduced in (a) and the catalyst introduced in step (a) are selected such that the catalyst in the non-polar phase (B) becomes enriched.
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Paragraph 0265; 0266
(2016/10/09)
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- METHOD FOR PRODUCING ALKANOL AMINES BY HOMOGENEOUSLY CATALYZED ALCOHOL AMINATION
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PROBLEM TO BE SOLVED: To provide a method for producing alkanol amines by alcohol amination of diols using ammonia under elimination of water. SOLUTION: The invention relates to a method for producing alkanol amines which comprise a primary amino group (-NH2) and a hydroxyl group (-OH), by alcohol amination of diols comprising two hydroxyl groups (-OH) using ammonia under elimination of water. The reaction is homogeneously catalyzed in the presence of at least one complex catalyst which contains at least one element selected from groups 8, 9 and 10 of the periodic table and at least one donor ligand. SELECTED DRAWING: None COPYRIGHT: (C)2016,JPO&INPIT
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Paragraph 0088; 0095
(2016/10/27)
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- Synthesis of common-sized heterocyclic compounds by intramolecular cyclization over halide cluster catalysts
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Five- to seven-membered common-sized heterocyclic compounds containing an oxygen, sulfur, or nitrogen were synthesized by the intramolecular condensation of α,ω-hydroxy, mercapto, or amino alkanes, respectively, over halide cluster complexes as a thermally stable molecular solid weak acid catalyst in the gas phase at temperatures ≥150 °C. From ω- mercapto and ω-amino alcohols, cyclic sulfides and amines were obtained, respectively. These unimolecular reactions are thermodynamically and kinetically favored.
- Nagashima, Sayoko,Sasaki, Tomoaki,Kamiguchi, Satoshi,Chihara, Teiji
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supporting information
p. 764 - 766
(2015/06/22)
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- Production of aminopyrrolidine
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Disclosed is a method for producing pyrollidine of formula (I) by reacting 1.4-butandiol (BDO) of formula (II) with ammoniac in the presence of hydrogen and a supported, metal-containing catalyser, characterised in that, prior to its reduction with hydrogen, the catalytically active mass of the catalyser contains oxygen-containing compounds of aluminium, copper, nickel and cobalt and oxygen-containing compounds of tin in the wt.% range of 0.2 to 5.0%, calculated as SnO, and in that the reaction is performed in the liquid phase at an absolute pressure in the range of 160 to 220 bar, at a temperature in the range of 160 to 230oC, using ammoniac at a molar ratio to the used BDO of 5 to 50 and in the presence of 1.0 to 4.5 wt.% hydrogen relative to the quantity of BDO used.
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Paragraph 0081; 0082; 0083
(2016/12/22)
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- HIV INTEGRASE INHIBITORS
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The present invention features compounds that are HIV integrase inhibitors and therefore are useful in the inhibition of HIV replication, the prevention and/or treatment of infection by HIV, and in the treatment of AIDS and/or ARC.
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- Importance of the Electron Correlation and Dispersion Corrections in Calculations Involving Enamines, Hemiaminals, and Aminals. Comparison of B3LYP, M06-2X, MP2, and CCSD Results with Experimental Data
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While B3LYP, M06-2X, and MP2 calculations predict the δG° values for exchange equilibria between enamines and ketones with similar acceptable accuracy, the M06-2X/6-311+G(d,p) and MP2/6-311+G(d,p) methods are required for enamine formation reactions (for example, for enamine 5a, arising from 3-methylbutanal and pyrrolidine). Stronger disagreement was observed when calculated energies of hemiaminals (N,O-acetals) and aminals (N,N-acetals) were compared with experimental equilibrium constants, which are reported here for the first time. Although it is known that the B3LYP method does not provide a good description of the London dispersion forces, while M06-2X and MP2 may overestimate them, it is shown here how large the gaps are and that at least single-point calculations at the CCSD(T)/6-31+G(d) level should be used for these reaction intermediates; CCSD(T)/6-31+G(d) and CCSD(T)/6-311+G(d,p) calculations afford δG° values in some cases quite close to MP2/6-311+G(d,p) while in others closer to M06-2X/6-311+G(d,p). The effect of solvents is similarly predicted by the SMD, CPCM, and IEFPCM approaches (with energy differences below 1 kcal/mol).
- Castro-Alvarez, Alejandro,Carneros, Héctor,Sánchez, Dani,Vilarrasa, Jaume
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supporting information
p. 11977 - 11985
(2016/01/09)
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- Pd-catalyzed decarboxylation of glutamic acid and pyroglutamic acid to bio-based 2-pyrrolidone
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In order to recycle nitrogen from nitrogen-rich waste streams, particularly protein waste, we studied the decarboxylation of pyroglutamic acid and glutamic acid in a one-pot reaction to bio-based 2-pyrrolidone. After the screening of a wide range of supported Pd and Pt catalysts, 5 wt% Pd/Al2O3 displayed the highest yield (70%) and selectivity (81%) for the decarboxylation of pyroglutamic acid in water at 250°C and under an inert atmosphere. Side products originate from consecutive reactions of 2-pyrrolidone; different reaction pathways are proposed to explain the presence of degradation products like propionic acid, γ-hydroxybutyric acid, γ-butyrolactone and methylamine. An extensive study of the reaction parameters was performed to check their influence on selectivity and conversion. This heterogeneous catalytic system was successfully extended to the conversion of glutamic acid.
- De Schouwer, Free,Claes, Laurens,Claes, Nathalie,Bals, Sara,Degrève, Jan,De Vos, Dirk E.
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p. 2263 - 2270
(2015/04/22)
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- · Uniform catalyst by using alcohol aminosilicone di-, tri-and a method of manufacturing a polyphenylenepolyamine
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The invention relates to a method for producing primary amines, which contain at least one functional group of the formula (-CH2-NH2) and at least one further primary amino group, by the alcohol amination of reactants, which contain at least one functional group of the formula (-CH2-OH) and at least one further functional group (-X), wherein (-X) is selected from hydroxyl groups and primary amino groups, using ammonia with removal of water, wherein the reaction is carried out in a homogeneously catalyzed manner in the presence of at least one complex catalyst containing at least one element selected from groups 8, 9 and 10 of the periodic table and at least one donor ligand.
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Paragraph 0099; 0114
(2016/10/09)
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- Process for Preparing Pyrrolidine
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Process for preparing pyrrolidine of the formula I by reacting 1,4-butanediol (BDO) of the formula II with ammonia in the presence of hydrogen and a supported, metal-containing catalyst, wherein the catalytically active mass of the catalyst, prior to its reduction with hydrogen, comprises oxygen-containing compounds of aluminum, copper, nickel and cobalt and in the range from 0.2 to 5.0% by weight of oxygen-containing compounds of tin, calculated as SnO, and the reaction is carried out in the liquid phase at an absolute pressure in the range from 160 to 220 bar, a temperature in the range from 160 to 230° C., using ammonia in a molar ratio to BDO used of from 5 to 50 and in the presence of 1.0 to 4.5% by weight of hydrogen, based on the amount of BDO used.
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Paragraph 0089
(2014/02/16)
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