- Supramolecular daisy chains
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Two series of self-complementary daisy chain monomers, in which a secondary ammonium ion-containing arm is grafted onto a macrocycle with either a [24]- or [25]crown-8 constitution, have been synthesized. In the solid- and 'gas'-phases, the parent [24]crown-8-based monomer forms dimeric superstructures, as revealed by X-ray crystallography and mass spectrometry, respectively. Elucidation of the complicated solution-phase behavior of this compound was facilitated by the synthesis and study of both deuterated, and fluorinated, analogues. These investigations revealed that the cyclic dimeric superstructure also dominates in solution, except when extremes of either concentration (low), temperature (high), or solvent polarity (highly polar, e.g., dimethyl sulfoxide) are employed. Whereas, upon aggregation, the [24]crown-8-based daisy chain monomers have the capacity to form stereoisomeric superstructures further complicating the study of this series of compounds. The assembly of [25]crown-8-based monomers gives only achiral superstructures. The weaker association exhibited between secondary dialkylammonium ions and crown ethers with a [25]crown-8 constitution, however, resulted in limited oligomerization-only dimeric and trimeric superstructures were formed at experimentally attainable concentrations-of [25]crown-8-based daisy chain monomers.
- Cantrill,Youn,Stoddart,Williams
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Read Online
- Effect of solvent used for crystallization on structure: Synthesis and characterization of bis(N,N-di(4-fluorobenzyl)dithiocarbamato-S,S′)M(II) (M = Cd, Hg) and usage as precursor for CdS nanophotocatalyst
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Bis(N,N-di(4-fluorobenzyl)dithiocarbamato-S,S′)M(II). (M = Cd (1), Hg (2)) were prepared and fully characterized. Recrystallization of 1 from its chloroform- acetonitrile and benzene-acetonitrile solutions yielded dimeric and trimeric complex 1, respectiv
- Ciattini, Samuele,Eswari, S.,Selvaganapathi, P.,Thirumaran, S.
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Read Online
- Tandem Fe/Zn or Fe/In Catalysis for the Selective Synthesis of Primary and Secondary Amines?via Selective Reduction of Primary Amides
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Tandem iron/zinc or iron/indium-catalysed reductions of various primary amides to amines under hydrosilylation conditions are reported under visible light activation. By a simple modification of the nature of the co-catalyst (Zn(OTf)2 vs In(OTf)3), Fe(CO)4(IMes) can promote the highly chemoselective reduction of primary amides into primary amines (21 examples, up to 93 % isolated yields) and secondary amines (8 examples, up to 51 % isolated yields), respectively. Notably, both benzamide and alkanamide derivatives can be reduced.
- Darcel, Christophe,Wu, Jiajun
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- Switching Selectivity in Copper-Catalyzed Transfer Hydrogenation of Nitriles to Primary Amine-Boranes and Secondary Amines under Mild Conditions
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A simple and efficient copper-catalyzed selective transfer hydrogenation of nitriles to primary amine-boranes and secondary amines with an oxazaborolidine-BH3 complex is reported. The selectivity control was achieved under mild conditions by switching the solvent and the copper catalysts. More than 30 primary amine-boranes and 40 secondary amines were synthesized via this strategy in high selectivity and yields of up to 95%. The strategy was applied to the synthesis of 15N labeled in 89% yield.
- Song, Hao,Xiao, Yao,Zhang, Zhuohua,Xiong, Wanjin,Wang, Ren,Guo, Liangcheng,Zhou, Taigang
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p. 790 - 800
(2022/01/11)
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- Platinum Nanoparticles Uniformly Dispersed on Covalent Organic Framework Supports for Selective Synthesis of Secondary Amines
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Covalent organic frameworks (COFs) with pore structures are talented supports for active components. In this report, COF has been rationally fabricated and served as host for growing uniformly dispersed platinum nanoparticles with a narrow size distribution (2 nm). The obtained hybrid Pt/COF exhibits high catalytic activity in the reductive amination of benzaldehyde towards secondary amines with a yield of 96 % and good recyclability. The preferable selectivity towards secondary amines could be attributed to synergistic effects of active platinum nanoparticles and COF, in which metallic Pt nanoparticles were uniformly dispersed with a positively charged surface. This work will open an avenue towards controlling the interaction between active metals and support as well as rational design of catalysts for demanding transformations for fine agrochemicals intermediates.
- Wang, Nan,Liu, Jianguo,Tang, Long,Wang, Chenguang,Li, Xinjun,Ma, Longlong
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- Aluminum Metal-Organic Framework-Ligated Single-Site Nickel(II)-Hydride for Heterogeneous Chemoselective Catalysis
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The development of chemoselective and heterogeneous earth-abundant metal catalysts is essential for environmentally friendly chemical synthesis. We report a highly efficient, chemoselective, and reusable single-site nickel(II) hydride catalyst based on robust and porous aluminum metal-organic frameworks (MOFs) (DUT-5) for hydrogenation of nitro and nitrile compounds to the corresponding amines and hydrogenolysis of aryl ethers under mild conditions. The nickel-hydride catalyst was prepared by the metalation of aluminum hydroxide secondary building units (SBUs) of DUT-5 having the formula of Al(μ2-OH)(bpdc) (bpdc = 4,4′-biphenyldicarboxylate) with NiBr2 followed by a reaction with NaEt3BH. DUT-5-NiH has a broad substrate scope with excellent functional group tolerance in the hydrogenation of aromatic and aliphatic nitro and nitrile compounds under 1 bar H2 and could be recycled and reused at least 10 times. By changing the reaction conditions of the hydrogenation of nitriles, symmetric or unsymmetric secondary amines were also afforded selectively. The experimental and computational studies suggested reversible nitrile coordination to nickel followed by 1,2-insertion of coordinated nitrile into the nickel-hydride bond occurring in the turnover-limiting step. In addition, DUT-5-NiH is also an active catalyst for chemoselective hydrogenolysis of carbon-oxygen bonds in aryl ethers to afford hydrocarbons under atmospheric hydrogen in the absence of any base, which is important for the generation of fuels from biomass. This work highlights the potential of MOF-based single-site earth-abundant metal catalysts for practical and eco-friendly production of chemical feedstocks and biofuels.
- Antil, Neha,Kumar, Ajay,Akhtar, Naved,Newar, Rajashree,Begum, Wahida,Dwivedi, Ashutosh,Manna, Kuntal
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p. 3943 - 3957
(2021/04/12)
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- Chemoselective transfer hydrogenation of nitriles to secondary amines with nickel(II) catalysts
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Herein we report the selective transfer hydrogenation (TH) of nitriles to secondary (2°) amines with simple Ni(II)-catalysts using ammonia borane (AB) as a source of hydrogen (H2). A bis(pyrazolylmethyl)pyridine (L1) or ethylenediamine (L4) ligated Ni(II) pre-catalyst, created in situ, could hydrogenate several aromatic- and aliphatic nitriles in full conversions and isolated yields of up to 88% under ambient temperature and in very short reaction times. Deuterium labelling experiments illustrated the incorporation of a proton on the nitrogen and hydride on the α-carbon of dibenzylamine. Using α-picoline borane, containing no dissociable protons, assisted with the postulation of a two-step TH mechanism of benzonitrile. AB was subjected to dehydrogenation and it was observed that a maximum of 2.96 equivalents of H2 gas could be generated from NiCl2?6H2O/L1.
- Vermaak, Vincent,Vosloo, Hermanus C.M.,Swarts, Andrew J.
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- Phosphine-Free Manganese Catalyst Enables Selective Transfer Hydrogenation of Nitriles to Primary and Secondary Amines Using Ammonia-Borane
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Herein we report the synthesis of primary and secondary amines by nitrile hydrogenation, employing a borrowing hydrogenation strategy. A class of phosphine-free manganese(I) complexes bearing sulfur side arms catalyzed the reaction under mild reaction conditions, where ammonia-borane is used as the source of hydrogen. The synthetic protocol is chemodivergent, as the final product is either primary or secondary amine, which can be controlled by changing the catalyst structure and the polarity of the reaction medium. The significant advantage of this method is that the protocol operates without externally added base or other additives as well as obviates the use of high-pressure dihydrogen gas required for other nitrile hydrogenation reactions. Utilizing this method, a wide variety of primary and symmetric and asymmetric secondary amines were synthesized in high yields. A mechanistic study involving kinetic experiments and high-level DFT computations revealed that both outer-sphere dehydrogenation and inner-sphere hydrogenation were predominantly operative in the catalytic cycle.
- Sarkar, Koushik,Das, Kuhali,Kundu, Abhishek,Adhikari, Debashis,Maji, Biplab
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p. 2786 - 2794
(2021/03/03)
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- Surface modification boosts exciton extraction in confined layered structure for selective oxidation reaction
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Extracting photogenerated species from bulk to surface is an essential process for gaining efficient semiconductor-based photocatalysis. However, compared with charged photogenerated carriers, neutral exciton exhibits negligible response to electric field. Accordingly, traditional strategies involving band-alignment construction for boosting directional transfer of charge carriers are impracticable for extracting bulk excitons. To this issue, we here propose that the extraction of bulk exciton could be effectively implemented by surface modification. By taking confined layered bismuth oxycarbonate (Bi2O2CO3) as an example, we highlight that the incorporation of iodine atoms on the surface could modify the micro-region electronic structure and hence lead to reduced energy of surface excitonic states. Benefiting from the energy gradient between bulk and surface excitonic states, iodine-modified Bi2O2CO3 possesses high-efficiency bulk exciton extraction, and hence exhibits promoted performance in triggering 1O2-mediated selective oxidation reaction. This work presents the positive role of surface modification in regulating excitonic processes of semiconductor-based photocatalysts. [Figure not available: see fulltext.].
- Jin, Sen,Wang, Hui,Li, Lei,Luo, Xiao,Sun, Xianshun,Zuo, Ming,Tian, Jie,Zhang, Xiaodong,Xie, Yi
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p. 1964 - 1969
(2021/10/25)
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- Preparation of nitrogen-doped carbon supported cobalt catalysts and its application in the reductive amination
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The use of non-noble metal catalysts with high activity is of great importance for organic transformations. Herein, nitrogen-doped carbon supported cobalt catalysts with high surface area up to 981.2 m2/g were prepared via the simple pyrolysis of cobalt coordinated organic polymers with silica as the hard template. The pyrolysis temperature showed a great effect on the structure and properties of the as-prepared catalysts. The Co@NC-800 catalyst with the pyrolysis temperature of 800 °C demonstrated a high activity for the selective reductive amination of carbonyl compounds to primary amines with ammonia and hydrogen. Structurally-diverse primary amines with yields in the range from 81.8% to 100% were attained under the optimal conditions. The Co@NC-800 catalyst could be reused without the loss of its activity. The Co@NC-800 catalyst demonstrated comparable activity as the reported heterogeneous noble metal catalysts.
- Yuan, Ziliang,Liu, Bing,Zhou, Peng,Zhang, Zehui,Chi, Quan
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p. 347 - 356
(2019/01/24)
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- Selective Synthesis of Secondary Amines from Nitriles by a User-Friendly Cobalt Catalyst
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Selective hydrogenation/reductive amination of nitriles to secondary amines catalyzed by an inexpensive and user-friendly cobalt complex, (Xantphos)CoCl2, is reported. The use of (Xantphos)CoCl2 and ammonia borane (NH3?BH3) combination affords the selective reduction of nitriles to symmetrical secondary amines, whereas the employment of (Xantphos)CoCl2 and dimethylamine borane (Me2NH?BH3) along with external amines produce unsymmetrical secondary amines and tertiary amines. The general applicability of this methodology is demonstrated by the synthesis of 43 symmetrical and unsymmetrical secondary and tertiary amines bearing diverse functionalities. (Figure presented.).
- Sharma, Dipesh M.,Punji, Benudhar
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supporting information
p. 3930 - 3936
(2019/07/12)
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- COMPOUNDS, SALTS THEREOF AND METHODS FOR TREATMENT OF DISEASES
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The present disclosure relates to compounds according to Formula (I), treating diseases.
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Paragraph 00272-00273
(2019/03/12)
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- Iron-Catalyzed Intramolecular C-H Amination of α-Azidyl Amides
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Iron-catalyzed intramolecular C-H amination of aliphatic azides has recently emerged as a powerful tool for the preparation of nitrogen heterocycles. This paper reports that α-azidyl amides can be converted in high efficacy to imidazolinone compounds via intramolecular C(sp3)-H amination by the action of a simple catalytic system composed of FeCl2 and a β-diketiminate ligand. The reactions provide a simple and atom-economical approach toward polysubstituted imidazolinones.
- Zhao, Xiaopeng,Liang, Siyu,Fan, Xing,Yang, Tonghao,Yu, Wei
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supporting information
p. 1559 - 1563
(2019/03/20)
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- Pd/TiO2-Photocatalyzed Self-Condensation of Primary Amines to Afford Secondary Amines at Ambient Temperature
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Symmetric secondary amines were synthesized by the self-condensation of primary amines over a palladium-loaded titanium dioxide (Pd/TiO2) photocatalyst. The reactions afforded a series of secondary amines in moderate to excellent isolated yields at ambient temperature (30 °C, in cyclopentyl methyl ether). Applicability for one-pot pharmaceutical synthesis was demonstrated by a photocatalytic reaction sequence of self-condensation of an amine followed by N-alkylation of the resulting secondary amine with an alcohol.
- Wang, Lyu-Ming,Kobayashi, Kensuke,Arisawa, Mitsuhiro,Saito, Susumu,Naka, Hiroshi
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supporting information
p. 341 - 344
(2018/12/11)
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- Cobalt complex, preparation method thereof, and application thereof in selective catalysis of transfer hydrogenation reaction of cyano group
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The invention discloses a cobalt complex, a preparation method thereof, and an application thereof in the selective catalysis of a transfer hydrogenation reaction of a cyano group. The structural formula of the cobalt complex is represented by formula I. The cobalt complex is prepared through a reaction of a cobalt salt and an NNP ligand or a PNP ligand under the protection of an inert atmosphere;and the chemical formula of the cobalt salt is CoX12, wherein X1 represents halogen, a sulfate radical, a perchlorate radical, a hexafluorophosphate radical, a hexafluoroantimonate radical, a tetrafluoroborate radical, a trifluoromethanesulfonate radical or a tetra(pentafluorophenyl)borate radical. The cobalt complex can be used in the selective catalysis of the transfer hydrogenation reaction ofthe cyano group to obtain a primary amine compound, a secondary amine compound and a tertiary amine compound, the primary amine compound, the secondary amine compound and the tertiary amine compoundare important intermediates in a series of subsequent functionalizing reactions, and the cobalt complex has a very high catalysis activity, and has great research values and a great application prospect.
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Paragraph 0165-0168
(2018/05/07)
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- Synthesis of Symmetric and Unsymmetric Secondary Amines from the Ligand-Promoted Ruthenium-Catalyzed Deaminative Coupling Reaction of Primary Amines
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The catalytic system generated in situ from the tetranuclear Ru-H complex with a catechol ligand (1/L1) was found to be effective for the direct deaminative coupling of two primary amines to form secondary amines. The catalyst 1/L1 was highly chemoselective for promoting the coupling of two different primary amines to afford unsymmetric secondary amines. The analogous coupling of aniline with primary amines formed aryl-substituted secondary amines. The treatment of aniline-d7 with 4-methoxybenzylamine led to the coupling product with significant deuterium incorporation on CH2 (18% D). The most pronounced carbon isotope effect was observed on the α-carbon of the product isolated from the coupling reaction of 4-methoxybenzylamine (C(1) = 1.015(2)). A Hammett plot was constructed from measuring the rates of the coupling reaction of 4-methoxyaniline with a series of para-substituted benzylamines 4-X-C6H4CH2NH2 (X = OMe, Me, H, F, CF3) (ρ = -0.79 ± 0.1). A plausible mechanistic scheme has been proposed for the coupling reaction on the basis of these results. The catalytic coupling method provides an operationally simple and chemoselective synthesis of secondary amine products without using any reactive reagents or forming wasteful byproducts.
- Arachchige, Pandula T. Kirinde,Lee, Hanbin,Yi, Chae S.
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p. 4932 - 4947
(2018/05/08)
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- Conversion of Primary Amines to Symmetrical Secondary and Tertiary Amines using a Co-Rh Heterobimetallic Nanocatalyst
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Symmetrical tertiary amines have been efficiently realized from amine and secondary amines via deaminated homocoupling with heterogeneous bimetallic Co2Rh2/C as catalyst (molar ratio Co:Rh=2:2). Unsymmetric secondary anilines were produced from the reaction of anilines with symmetric tertiary amines. The Co2Rh2/C catalyst exhibited very high catalytic activity towards a wide range of amines and could be conveniently recycled ten times without considerable leaching. (Figure presented.).
- Chung, Hyunho,Han, Seulgi,Chung, Young Keun,Park, Ji Hoon
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supporting information
p. 1267 - 1272
(2018/02/12)
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- Nano-sized La0.5Ca0.5CoO3-mediated reduction by nabh4 of aryl nitriles to bis-(benzyl) amines
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Nano-sized La0.5Ca0.5CoO3 perovskite, which was produced via the sol-gel method, was an efficient heterogeneous catalyst in combination with NaBH4 for the rapid chemoselective reduction of aryl nitriles to bis-(benzyl)amines at 40°C in good to excellent yields. The physico-chemical properties of the catalyst were characterized by means of differential thermal analysis (DTA), thermogravimetric analysis (TGA), X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDX) and particle size distributions images. The results show that nanoparticles have regular shapes with well-defined crystal faces with an average size of 30 nm.
- Bavandi, Hossein,Shiri, Ali,Tavakkoli, Haman
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p. 3330 - 3334
(2017/05/29)
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- Rational design, synthesis, and structure–activity relationships of 5-amino-1H-pyrazole-4-carboxylic acid derivatives as protein tyrosine phosphatase 1B inhibitors
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A series of novel amino-carboxylic based pyrazole as protein tyrosine phosphatase 1B (PTP1B) inhibitors were designed on the basis of structure-based pharmacophore model and molecular docking. Compounds containing different hydrophobic tail (1,2-diphenyl ethanone, oxdiadizole and dibenzyl amines) were synthesized and evaluated in PTP1B enzymatic assay. Structure–activity relationship based optimization resulted in identification of several potent, metabolically stable and cell permeable PTP1B inhibitors.
- Basu, Sujay,Prathipati, Philip,Thorat, Sachin,Ansari, Shariq,Patel, Meena,Jain, Vaibhav,Jinugu, Ramana R.,Niranjan, Sanjay,De, Siddhartha,Reddy, Satyanarayana
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supporting information
p. 67 - 74
(2016/12/18)
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- Cobalt-Catalyzed Synthesis of Aromatic, Aliphatic, and Cyclic Secondary Amines via a "hydrogen-Borrowing" Strategy
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The replacement of precious metals with inexpensive, less toxic, and earth-abundant elements in typical noble-metal-mediated organic transformations is a major goal in current synthetic chemistry and industries. The metal-catalyzed N-alkylation of amines with other amines through a "hydrogen-borrowing" principle represents a green and atom-economical reaction for the synthesis of secondary amines. However, catalysts developed thus far that are effective for this process remain quite scarce and are only limited to a few ruthenium and iridium complexes. In this work, we present a cobalt-catalyzed selective alkylation of amines with amines to synthesize a large variety of secondary amines. A range of amine substrates have been converted to the corresponding products through hetero- or homocoupling between amines. Cyclic sec-amines are also achieved from diamine precursors as rare examples.
- Yin, Zhiwei,Zeng, Haisu,Wu, Jing,Zheng, Shengping,Zhang, Guoqi
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p. 6546 - 6550
(2016/10/14)
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- Mild and Selective Cobalt-Catalyzed Chemodivergent Transfer Hydrogenation of Nitriles
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Herein, we describe a selective cobalt-catalyzed chemodivergent transfer hydrogenation of nitriles to synthesize primary, secondary, and tertiary amines. The solvent effect plays a key role for the selectivity control. The general applicability of this procedure was highlighted by the synthesis of more than 70 amine products bearing various functional groups in high chemoselectivity. Moreover, this mild system achieved >2000 TONs (turnover numbers) for the transfer hydrogenation of nitriles.
- Shao, Zhihui,Fu, Shaomin,Wei, Mufeng,Zhou, Shaolin,Liu, Qiang
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supporting information
p. 14653 - 14657
(2016/11/23)
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- Cationic Iridium and Rhodium Complexes with C-N Chelating Primary Benzylic Amine Ligands as Potent Catalysts for Hydrogenation of Unsaturated Carbon-Nitrogen Bonds
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Cationic half-sandwich C-N chelating Ir and Rh complexes [Cp?M(NCCH3){2(N,C)-NH2CR2-2-C6H4}]+SbF6- (1a, M = Ir, R = CH3; 1b, M = Ir, R = C6H5; 2a, M = Rh, R = CH3; 2b, M = Rh, R = C6H5) are synthesized by AgSbF6-mediated halide abstraction from neutral azametallacycles derived from tritylamine or cumylamine and are fully characterized by NMR spectroscopy and X-ray crystallography. The treatment of the cationic complex 1b with H2 gas under ambient conditions in the presence of triethylamine in THF-d8 quantitatively yielded hydrido(amine) complex [Cp?Ir(H){2(N,C)-NH2C(C6H5)2-2-C6H4}] (4). The C-N chelating Ir complex shows a higher catalytic activity than an N-N chelating complex, [Cp?Ir(NCCH3)(Tscydn)]+SbF6- (3; Tscydn = N-(p-toluenesulfonyl)-1,2-cyclohexanediamime), that has been previously used for the asymmetric hydrogenation of acyclic imines. For example, the cationic Ir complex 1a promoted the hydrogenation of N-(1-phenylethylidene)benzylamine under 30 atm at 30 °C in the presence of excess AgSbF6 to produce the corresponding amine in 97% yield within 2 h. The cationic Rh complexes 2 serve as efficient catalysts for hydrogenative condensation of nitriles in the presence of AgSbF6, producing dibenzylamines selectively even at 60 °C.
- Sato, Yasuhiro,Kayaki, Yoshihito,Ikariya, Takao
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p. 1257 - 1264
(2016/06/01)
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- C70 as a Photocatalyst for Oxidation of Secondary Benzylamines to Imines
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Photosensitive C70 was used for the catalytic oxidation of benzylamines to the corresponding imines. The advantages of using C70 compared to C60 or other commonly used photosensitizers such as tetraphenylporphyrin (TPP) ar
- Kumar, Rakesh,Glei?ner, Eva H.,Tiu, Elisha Gabrielle V.,Yamakoshi, Yoko
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supporting information
p. 184 - 187
(2016/02/05)
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- Selective Hydrogenation of Nitriles to Primary Amines Catalyzed by a Cobalt Pincer Complex
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The catalytic hydrogenation of nitriles to primary amines represents an atom-efficient and environmentally benign reduction methodology in organic chemistry. This has been accomplished in recent years mainly with precious-metal-based catalysts, with a single exception. Here we report the first homogeneous Co-catalyzed hydrogenation of nitriles to primary amines. Several (hetero)aromatic, benzylic, and aliphatic nitriles undergo hydrogenation to the corresponding primary amines in good to excellent yields under the reaction conditions.
- Mukherjee, Arup,Srimani, Dipankar,Chakraborty, Subrata,Ben-David, Yehoshoa,Milstein, David
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supporting information
p. 8888 - 8891
(2015/08/03)
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- Three-component asymmetric catalytic ugi reaction - Concinnity from diversity by substrate-mediated catalyst assembly
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The first chiral catalyst for the three-component Ugi reaction was identified as a result of a screen of a large set of different BOROX catalysts. The BOROX catalysts were assembled in situ from a chiral biaryl ligand, an amine, water, BH3×SMe2, and an alcohol or phenol. The catalyst screen included 13 different ligands, 12 amines, and 47 alcohols or phenols. The optimal catalyst system (LAP 8-5-47) provided α-amino amides from an aldehyde, a secondary amine, and an isonitrile with excellent asymmetric induction. The catalytically active species is proposed to be an ion pair that consists of the chiral boroxinate anion and an iminium cation. Harmonious arrangement of parts: A screen of BOROX catalysts that were generated in situ from 13 different ligands and 47 alcohols led to the identification of an effective combination for the catalytic asymmetric three-component Ugi reaction. Experimental results suggest that the catalyst is a chiral polyborate anion, which then forms an ion pair with the iminium cation that is generated from aldehyde and secondary amine.
- Zhao, Wenjun,Huang, Li,Guan, Yong,Wulff, William D.
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supporting information
p. 3436 - 3441
(2014/04/03)
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- Pt-Sn/γ-Al2O3-catalyzed highly efficient direct synthesis of secondary and tertiary amines and imines
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Versatile syntheses of secondary and tertiary amines by highly efficient direct N-alkylation of primary and secondary amines with alcohols or by deaminative self-coupling of primary amines have been successfully realized by means of a heterogeneous bimetallic Pt-Sn/γ-Al2O3 catalyst (0.5 wt % Pt, Pt/Sn molar ratio=1:3) through a borrowing-hydrogen strategy. In the presence of oxygen, imines were also efficiently prepared from the tandem reactions of amines with alcohols or between two primary amines. The proposed mechanism reveals that an alcohol or amine substrate is initially dehydrogenated to an aldehyde/ketone or NH-imine with concomitant formation of a [PtSn] hydride. Condensation of the aldehyde/ketone species or deamination of the NH-imine intermediate with another molecule of amine forms an N-substituted imine which is then reduced to a new amine product by the in-situ generated [PtSn] hydride under a nitrogen atmosphere or remains unchanged as the final product under an oxygen atmosphere. The Pt-Sn/γ-Al2O 3 catalyst can be easily recycled without Pt metal leaching and has exhibited very high catalytic activity toward a wide range of amine and alcohol substrates, which suggests potential for application in the direct production of secondary and tertiary amines and N-substituted imines.
- He, Wei,Wang, Liandi,Sun, Chenglin,Wu, Kaikai,He, Songbo,Chen, Jiping,Wu, Ping,Yu, Zhengkun
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experimental part
p. 13308 - 13317
(2012/02/02)
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- A biomimetic electrocatalytic system for the atom-economical chemoselective synthesis of secondary amines
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A facile one-pot oxidation-imine formation-reduction route to secondary amines can be achieved electrolytically from primary amines. This atom-economical 1ox-mediated sequence, leaving ammonia as the sole byproduct, allows the rapid chemoselect
- Largeron, Martine,Fleury
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supporting information; experimental part
p. 883 - 886
(2009/07/25)
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- Iridium-catalyzed condensation of primary amines to form secondary amines
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Symmetric secondary amines are readily obtained by heating a neat primary amine with 0.5 mol% of bis(dichloro[h5-pentamethylcyclopentadienyl] iridium). The products are isolated by direct distillation in good yields. Georg Thieme Verlag Stuttgart - New York.
- Lorentz-Petersen, Linda L. R.,Jensen, Paw,Madsen, Robert
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experimental part
p. 4110 - 4112
(2011/02/27)
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- Process for reductively aminating ketones and aldehydes with aqueous amines and catalysts suitable therefor
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A process for preparing amines of the general formula (I)[in-line-formulae]R1R2CHNR3R4??(I)[/in-line-formulae]in which R1, R2, R3 and R4 are each independently hydrogen, straight-chain or branched, halogenated or halogen-free C1-C12-alkyl, C3-C12-cycloalkyl, C6-C10-aryl or C7-C11-aralkyl, by catalytic, hydrogenating amination of carbonyl compounds of the general formula (II)[in-line-formulae]R1—C(═O)—R2??(II)[/in-line-formulae]with nitrogen compounds of the general formula (III)[in-line-formulae]HNR3R4??(III)[/in-line-formulae]in the presence of bifunctional catalyst systems comprising a.) a hydrogenation-active catalyst component comprising one or more metals of transition group 8 of the Periodic Table and b.) one or more solid, acidic cocatalysts, wherein the hydrogenating amination is carried out in the presence of aqueous ammonia or aqueous amine of the formula (III) and at least one organic solvent miscible with ammonia or the aqueous amine of the formula (III).
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Page/Page column 2
(2008/06/13)
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- Potent Nonclassical Nucleoside Antiviral Drugs Based on the N,N-Diarylformamidine Concept
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New formamidine-3TC (3TC = 2′,3′-dideoxy-3′-thiacytidine) analogues have been synthesized through various methods, and their antiviral activities (HIV, HBV) have been evaluated in vitro. Anti-HIV-1 in acutely infected MT-4 cells and peripheral blood monoc
- Anastasi, Carole,Hantz, Olivier,De Clercq, Erik,Pannecouque, Christophe,Clayette, Pascal,Dereuddre-Bosquet, Nathalie,Dormont, Dominique,Gondois-Rey, Fran?oise,Hirsch, Ivan,Kraus, Jean-Louis
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p. 1183 - 1192
(2007/10/03)
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- Hydroamination of carbonyl compounds with oximes
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N-alkyl(cycloalkyl)benzylamines, p-fluorobenzylamines, (1-phenylethyl) amines, [1-(p-fluorophenyl)ethyl]amines were synthesized by hydroamination of aldehydes and ketones with oximes.
- Tarasevich,Kozlov
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p. 379 - 383
(2007/10/03)
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- Chemoselective reductive alkylation of ammonia with carbonyl compounds: Synthesis of primary and symmetrical secondary amines
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An efficient, general procedure for highly chemoselective reductive mono-alkylation of ammonia with ketones is reported. Treatment of ketones with ammonia in ethanol and titanium(IV) isopropoxide, followed by in situ sodium borohydride reduction, and a straightforward workup afforded primary amines in good to excellent yields. Reductive alkylation of ammonia with aldehydes, on the other hand, afforded the corresponding symmetrical secondary amines selectively.
- Miriyala, Bruhaspathy,Bhattacharyya, Sukanta,Williamson, John S.
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p. 1463 - 1471
(2007/10/03)
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- Turning the product selectivity of nitrile hydrogenation from primary to secondary amines by precise modification of Pd/SiC catalysts using NiO nanodots
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The selectivity of supported metal catalysts is mainly determined by the active metallic component, and thus turning the selectivity to a completely different product is rarely achieved by modification of the catalysts. Hydrogenation of nitriles is an efficient and environmentally benign route for the synthesis of valuable amines, but it usually produces mixtures of primary, secondary and even tertiary amines. Herein we report that the selectivity of Pd/SiC catalysts for the hydrogenation of nitriles with H2 can be turned from primary to secondary amines by modification of NiO nanodots. In the modified catalysts, the NiO nanodots act as reactive sites to consume hydrogen radicals on the Pd surface, and thus prolong the lifetime of an imine intermediate that determines the product selectivity. Under mild conditions (30 °C, atmospheric H2), Pd/SiC and NiO-Pd/SiC catalysts exhibit high selectivity to primary (94%) and secondary (99%) amines, respectively.
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