- 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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- Nickel Complexes Bearing N,N,O-Tridentate Salicylaldiminato Ligand: Efficient Catalysts for Imines Formation via Dehydrogenative Coupling of Primary Alcohols with Amines
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Treatment of salicylaldiminato ligand L1H-L2H (L1H = 2,4-di-tert-butyl-6-((quinolin-8-ylimino)methyl)phenol; L2H = 2,4-di-tert-butyl-6-(((2-(diethylamino)ethyl)imino)methyl)phenol) with Ni(OAc)2·4H2O in refluxing ethanol afforded nickel complexes [(L1)Ni(OAc)] (1) and [(L2)Ni(OAc)] (2), respectively. Reaction of L3H (L3H = (2,4-di-tert-butyl-6-(((2-(pyridin-2-yl)ethyl)imino)methyl)phenol)) with Ni(OAc)2·4H2O in the presence of excess triethylanmine gave the dual ligands coordinated nickel complex [(L2)2Ni] (3). Complexes 1-3 were well characterized by high-resolution mass spectrometry, infrared spectroscopy, elemental analysis, and X-ray diffraction analysis. All the three Ni(II) complexes exhibited efficient activity and good selectivity in the acceptorless dehydrogenative coupling of alcohols and amines to produce imines and diimines. The present protocol provides an atom-economical and sustainable route for the synthesis of various imine derivatives by employing an earth-abundant nickel salt and easily prepared salicylaldiminato ligands.
- Han, Zhangang,Hao, Zhiqiang,Lin, Jin,Lu, Guo-Liang,Zhang, Junhua,Zhang, Xiaoying
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p. 3843 - 3853
(2021/11/18)
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- Trimethyl Borate-Catalyzed, Solvent-Free Reductive Amination
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Solvent-free reductive amination of aldehydes and ketones with aliphatic and aromatic amines in high-to-excellent yields has been achieved with sub-stoichiometric trimethyl borate as promoter and ammonia borane as reductant.
- Ramachandran, P. Veeraraghavan,Choudhary, Shivani,Singh, Aman
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p. 4274 - 4280
(2021/03/09)
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- Synthesis, characterization, and antibacterial activity of dibenzildithiocarbamate derivates and Ni(II)–Cu(II) coordination compounds
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In this work, the study of the synthesis methodology to obtain dibenzylamine derivates as intermediates for the formation of dithicarbamate ligands (DTC) and its coordination compounds was conducted. Four molecules derived from dibenzylamine were synthesized by two methodologies: classical (reflux) and microwave. From these amines, Four dithiocarbamate ligands (DTC): dibenzyldithiocarbamate, N-benzyl-1-(4-methoxyphenyl)dithiocarbamate, N-benzyl-1-(4-chlorophenyl)dithiocarbamate, and N-benzyl-1-(3-nitrophenyl)dithiocarbamate, and eight coordination complexes with general formula [M(DTC)2]nH2O (M= Cu(II) and Ni(II)) were obtained. All the compounds were characterized using different spectroscopic and thermal techniques such as Fourier-transform infrared spectroscopy (FT-IR), ultraviolet–visible spectroscopy (UV–VIS), proton and carbon-13 nuclear magnetic resonance (1H and 13C NMR), thermogravimetric analysis–differential scanning calorimetry (TGA-DSC). Additionally, it was possible to characterize two new crystalline phases of salts through single-crystal X-ray diffraction: dibenzyl ammonium nitrate and N-benzyl-1-(3-nitrophenyl)ammonium chloride. Additionally, microbial inhibition tests were conducted using the dibenzildithiocarbamate derivates. All DTC compounds showed important activity against Pseudomonas aeruginosa and Staphylococcus aureus but less sensitivity against Escherichia coli and Mycobacterium smegmatis. Among the coordination compounds, only [Cu(N-benzyl-1-(3-nitrophenyl)dithiocarbamate)2] presented a moderate activity against M. smegmatis mc2 155.
- Amaya-Flórez, Andres,Aranaga, Carlos,D'Vries, Richard F.,Ellena, Javier,Flórez-López, Edwin,Macías, Mario,Pastrana-Dávila, Andrea
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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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- Efficient One-Pot Reductive Aminations of Carbonyl Compounds with Aquivion-Fe as a Recyclable Catalyst and Sodium Borohydride
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A one-pot reductive amination of aldehydes and ketones with NaBH4 was developed with a view to providing efficient, economical and greener synthetic conditions. A recyclable iron-based Lewis catalyst, Aquivion-Fe, was used to promote imine formation in cyclopentyl methyl ether, followed by the addition of a small amount of methanol to the reaction mixture to enable C=N reduction by NaBH4. The protocol, applied to a wide number of amines and carbonyl compounds, resulted in ever complete conversion of these latter with excellent chemoselectivity towards the expected amination products in the most cases. Isolated yields, determined for a selection of the screened substrates, were found consistent with the previously obtained conversion and selectivity data. Cinacalcet, an important active pharmaceutical ingredient, was efficiently prepared by the title procedure.
- Airoldi, Veronica,Piccolo, Oreste,Roda, Gabriella,Appiani, Rebecca,Bavo, Francesco,Tassini, Riccardo,Paganelli, Stefano,Arnoldi, Sebastiano,Pallavicini, Marco,Bolchi, Cristiano
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supporting information
p. 162 - 168
(2019/12/11)
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- Synthesis and characterization of Ni(II) complexes with functionalized dithiocarbamates: New single source precursors for nickel sulfide and nickel-iron sulfide nanoparticles
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Six Ni(II) complexes, bis(N-benzyl-N-substituted benzyldithiocarbamato-S,S′)nickel(II) (1–3), (N-benzyl-N-substituted benzyldithiocarbamato-S,S′)(thiocyanato-N)(triphenylphosphine)nickel(II) (4–6), [Substituted benzyl=4-hydroxybenzyl (1, 4), 4-methoxybenzyl (2, 5), 4-chlorobenzyl (3, 6)] complexes have been synthesized and characterized by elemental analysis, IR, UV–Vis and NMR (1H and 13C) spectroscopy. Upfield shift of NCS2 carbon signals of heteroleptic complexes compared to homoleptic complexes supports the back bonding effect of triphenylphosphine. Structures of complexes 1, 4, 5 and 6 have been obtained by single crystal X-ray diffraction. The coordination geometry around nickel is a distorted square planar in all the complexes. Intramolecular Ni?H-C anagostic interaction is observed in 4. Various non-covalent interactions such as C-H?π(chelate), C-H?π and C-H?X (X = O and Cl) lead to supramolecular aggregation. [Ni(dbdtc)2] and [Ni(dbdtc)3][FeCl4] (dbdtc = N,N-dibenzyldithiocarbamate) were used to prepare monometallic sulfide (nickel sulfide), bimetallic sulfide (iron-nickel sulfide) nanoparticles. TEM images of nickel sulfide and iron-nickel sulfide reveal that the particles are oval shape and ultrafine (~5–10 nm), respectively.
- Sathiyaraj,Thirumaran,Ciattini, Samuele,Selvanayagam
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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 0173-0176
(2018/05/07)
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- Expanding the Boundaries of Water-Tolerant Frustrated Lewis Pair Hydrogenation: Enhanced Back Strain in the Lewis Acid Enables the Reductive Amination of Carbonyls
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The development of a boron/nitrogen-centered frustrated Lewis pair (FLP) with remarkably high water tolerance is presented. As systematic steric tuning of the boron-based Lewis acid (LA) component revealed, the enhanced back-strain makes water binding increasingly reversible in the presence of relatively strong base. This advance allows the limits of FLP's hydrogenation to be expanded, as demonstrated by the FLP reductive amination of carbonyls. This metal-free catalytic variant displays a notably broad chemoselectivity and generality.
- Dorkó, éva,Szabó, Márk,Kótai, Bianka,Pápai, Imre,Domján, Attila,Soós, Tibor
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supporting information
p. 9512 - 9516
(2017/08/01)
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- A facile synthesis of stable β-amino-N-/O-hemiacetals through a catalyst-free three-component Mannich-type reaction
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A practical, straightforward and one-step procedure for the synthesis of novel and stable β-amino-N-/O-hemiacetals (i.e. γ-aminoalcohols) is provided. The title compounds were obtained in good to excellent yields through an uncatalyzed three-component reaction by treatment of secondary amines with polyformaldehyde and electron-rich alkenes in acetonitrile as solvent at ambient temperature. The reactions proceeded with the formation of iminium ions, through a Mannich-type reaction, as the key intermediates for the generation of the target products. Single crystal X-ray analysis of derivative 4l confirmed unequivocally the structure and stability of the obtained compounds.
- Abonia, Rodrigo,Castillo, Juan C.,Garay, Alexander,Insuasty, Braulio,Quiroga, Jairo,Nogueras, Manuel,Cobo, Justo,D'Vries, Richard
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supporting information
p. 1490 - 1494
(2017/03/23)
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- Iridium(I) Complexes Bearing a Noninnocent PNP-Pincer-Type Phosphaalkene Ligand: Catalytic Application in the Base-Free N-Alkylation of Amines with Alcohols
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A series of IrI complexes [Ir(L)(PPEP?)] [L = Cl- (3), CO (4), tBuNC (5), PMe3 (6), PPh3 (7)], coordinated with a PNP-pincer-type phosphaalkene ligand bearing a dearomatized pyridine ring (PPEP?), have been prepared and their catalytic properties for the dehydration/condensation of amines with alcohols has been examined. The catalytic reactions successfully proceed under base-free conditions to give N-alkylated amines and their dehydrogenation derivatives (imines). The product selectivity is dependent on L coordinated with Ir(PPEP?). Complexes 4 and 5 that contain π-accepting ligands (CO, tBuNC) form N-alkylated amines as the major products in a closed system using a nitrogen-gas-filled Schlenk tube. In contrast, complex 7 that contain PPh3 as L produces imines as the major products under a nitrogen-gas flow. The reason for the selectivity change depending on L is discussed based on stoichiometric reactions using model compounds of presumed catalytic intermediates. PNP-pincer-type phosphaalkene complexes of IrI bearing a dearomatized pyridine ring have been found to catalyze the dehydration/condensation of amines with alcohols under base-free conditions to afford N-alkylated amines and imines in high yields. The product selectivity can be controlled by the choice of auxiliary ligands (L) as well as the reaction conditions.
- Chang, Yung-Hung,Tanigawa, Ippei,Taguchi, Hiro-Omi,Takeuchi, Katsuhiko,Ozawa, Fumiyuki
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p. 754 - 760
(2016/03/01)
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- Effect of functionlization of N, N -dibenzyldithiocarbamate: Synthesis, spectral and structural studies on bis(N -benzyl- N -(4-methoxybenzyl)dithiocarbamato-S,S′)zinc(II) and bis(N -benzyl- N -(4-cholrobenzyl)dithiocarbamato-S,S′)cadmium(II) and their use for the preparation of MS (M = Zn, Cd)
-
Bis(N-benzyl-N-(4-methoxybenzyl)dithiocarbamato-S,S′)zinc(II) (1) and bis(N-benzyl-N-(4-chlorobenzyl)dithiocarbamato-S,S′)cadmium(II) (2) have been prepared and characterized by elemental analysis, IR and NMR (1H and 13C) spectroscopy and single-crystal X-ray analysis. Complexes 1 and 2 exist as monomer and dimer, respectively. Crystal structures of 1 and 2 confirm the presence of four coordinated zinc in a distorted tetrahedral arrangement and five coordinated cadmium in a distorted square pyramid arrangement, respectively. Both the complexes are further stabilized by various interactions such as C-H···S, C-H···N, C-H···O and C-H···π (chelate). C-H···O interaction leads to the formation of dimer in complex 1. In complex 2, C-H···π (chelate) interaction runs in opposite directions which results in the polymeric chain. ZnS and CdS have been prepared from 1 and 2, respectively, and characterized by powder X-ray diffraction, SEM, UV-Vis and fluorescence spectroscopy. The X-ray diffraction pattern confirms the wurtzite phase of as-prepared ZnS and CdS.
- Gomathi, Govindaraju,Sathiyaraj, Ethiraj,Thirumaran, Subbiah,Ciattini, Samuele
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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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- Nucleophilic substitution reactions of meta- and para-substituted benzylamines with benzyl bromide in methanol medium
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The rates of reactions of para- and meta-substituted benzylamines with benzyl bromide were measured using conductivity technique in methanol medium. The reaction followed a total second-order path. The end product of the reaction is identified as dibenzylamine (X-C6H4CH2NHCH2C6H5) (where X = 4-OCH3, 4-CH3, H, 4-Cl, 4-CF3, 3-CF3, 4-NO2). Electron-withdrawing groups such as chloro, trifluoromethyl, and nitro in the benzylamine moiety decrease the rate of the reaction, whereas the electron-donating groups, such as methoxy and methyl, increase the rate compared to the unsubstituted compound. A mechanism involving formation of an SN 2-type transition state between the amine nucleophiles and the benzyl bromide and its subsequent decomposition is proposed. Hammett's reaction constant ρ of the reaction decreases with an increase in temperature. Activation parameters were calculated and discussed.
- Ravi,Sanjeev,Jagannadham,Skelton, Adam A.
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- Efficient metal-free hydrosilylation of tertiary, secondary and primary amides to amines
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Hydrosilylation of secondary and tertiary amides to amines is described using catalytic amounts of B(C6F5)3. The organic catalyst enables the reduction of amides with cost-efficient, non-toxic and air stable PMHS and TMDS hydrosilanes. The methodology was successfully extended to the more challenging reduction of primary amides.
- Blondiaux, Enguerrand,Cantat, Thibault
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supporting information
p. 9349 - 9352
(2014/08/05)
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- Ultrasound-assisted solventless synthesis of amines by in situ oxidation/reductive amination of benzyl halides
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Ultrasound-assisted solventless oxidation/reductive amination of benzyl halides was developed as a facile, efficient, and environmental friendly method toward N-alkylated amines. Aldehydes were formed in situ by oxidation of organic halides with N-methylmorpholine N-oxide (NMO), followed by direct reductive amination with amines using sodium borohydride and montmorillonite K-10 catalyst as the reducing system. This green and simple procedure enables N-alkylated amines to be prepared in good to excellent yields with high selectivity of the monoalkylation. This journal is the Partner Organisations 2014.
- Khumraksa, Bannarak,Phakhodee, Wong,Pattarawarapan, Mookda
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p. 20454 - 20458
(2014/06/09)
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- Tandem synthesis of amides and secondary amines from esters with primary amines under solvent-free conditions
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An iridium(III)-catalyzed tandem synthesis of amides and amines from esters under solvent-free conditions is described. A commercially available iridium(III) complex, [Cp*IrCl2]2, with sodium acetate showed the best activity for the synthesis of amides and secondary amines. The amide was formed by ester-amide exchange which generates an alcohol in situ which is subsequently transformed to a secondary amine via hydrogen autotransfer. This synthetic protocol with high atom economy generates water as the sole by-product and can afford amides and amines from various esters in a one-pot reaction, expanding the synthetic versatility of ester transformations.
- Lee, Jeongbin,Muthaiah, Senthilkumar,Hong, Soon Hyeok
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p. 2653 - 2660
(2014/09/17)
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- Ruthenium-catalyzed N-alkylation of amines with alcohols under mild conditions using the borrowing hydrogen methodology
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Using a simple amino amide ligand, ruthenium-catalyzed one-pot alkylation of primary and secondary amines with simple alcohols was carried out under a wide range of conditions. Using the alcohol as solvent, alkylation was achieved under mild conditions, even as low as room temperature. Reactions occurred with high conversion and selectivity in many cases. Reactions can also be carried out at high temperatures in organic solvent with high selectivity using stoichiometric amounts of the alcohol.
- Enyong, Arrey B.,Moasser, Bahram
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p. 7553 - 7563
(2014/09/17)
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- A general and selective copper-catalyzed reduction of secondary amides
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In situ-generated cationic copper/pybox catalyst systems allow for the selective reduction of secondary amides into the corresponding amines under mild conditions. This novel protocol has a wide substrate scope and shows good functional group tolerance. The Royal Society of Chemistry 2012.
- Das, Shoubhik,Join, Benoit,Junge, Kathrin,Beller, Matthias
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supporting information; experimental part
p. 2683 - 2685
(2012/04/04)
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- Selective synthesis of secondary amines by Pt nanowire catalyzed reductive amination of aldehydes and ketones with ammonia
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The process of the reductive amination of aldehydes or ketones in the presence of ammonia using unsupported ultra-thin Pt nanowires has been developed. This catalytic system shows high activity and selectivity under mild reaction conditions.
- Qi, Fenqiang,Hu, Lei,Lu, Shuanglong,Cao, Xueqin,Gu, Hongwei
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supporting information
p. 9631 - 9633
(2012/10/29)
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- Ni-Cu/γ-Al2O3 catalyzed N-alkylation of amines with alcohols
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A γ-Al2O3 supported Ni and Cu bimetallic nanoparticles catalyst (45 wt.% Ni, Ni/Cu mass ratio = 4.5/1.0) is prepared by electroless plating method for the N-alkylation of amines with alcohols under base and Lewis acidic cocatalyst conditions. The catalyst afforded fast conversions, high selectivity for amines and alcohols with various structures under an Ar atmosphere in o-xylene. Furthermore, catalyst still has a stable catalytic activity after two consecutive cycles regenerated.
- Sun, Jian,Jin, Xiaodong,Zhang, Fengwei,Hu, Wuquan,Liu, Juntao,Li, Rong
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experimental part
p. 30 - 33
(2012/07/17)
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- Efficient Iridium-thioether-dithiolate catalyst for β-alkylation of alcohols and selective imine formation via N-alkylation reactions
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An Ir-thioether-dithiolate complex, [Cp*Ir(η3-tpdt)] (Cp* = η5-C5Me5, tpdt = S(CH 2CH2S-)2), is evaluated for its catalytic potential in the β-alkylation of secondary alcohols and the N-alkylation of amines with alcohols. The β-alkylation reaction proceeded efficiently under low catalyst loading and in the absence of any sacrificial hydrogen additive with only water being formed as the coproduct. The same complex also proved to be efficient in the synthesis of imines via the N-alkylation reaction. The predominant formation of imines, rather than amines, in this reaction is a deviation from the product selectivity usually observed in similar N-alkylation reactions involving organometallic catalysts.
- Xu, Chang,Goh, Lai Yoong,Pullarkat, Sumod A.
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experimental part
p. 6499 - 6502
(2012/02/06)
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- Zinc-catalyzed chemoselective reduction of tertiary and secondary amides to amines
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General and convenient procedures for the catalytic hydrosilylation of secondary and tertiary amides under mild conditions have been developed. In the presence of inexpensive zinc catalysts, tertiary amides are easily reduced by applying monosilanes. Key to success for the reduction of the secondary amides is the use of zinc triflate and disilanes with dual Si-H moieties. The presented hydrosilylations proceed with excellent chemoselectivity in the presence of sensitive ester, nitro, azo, nitrile, olefins, and other functional groups, thus making the method attractive for organic synthesis.
- Das, Shoubhik,Addis, Daniele,Junge, Kathrin,Beller, Matthias
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experimental part
p. 12186 - 12192
(2011/11/07)
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- Ruthenium-catalyzed nitro and nitrile compounds coupling with alcohols: Alternative route for N-substituted amine synthesis
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The one-pot synthesis of N-substituted secondary amines from nitrobenzenes and benzonitriles has been developed (see scheme). This report presents a versatile and simple method for the synthesis of N-substituted amines in excellent yield and high efficiency from nitro and nitrile compounds with alcohols.
- Cui, Xinjiang,Zhang, Yan,Shi, Feng,Deng, Youquan
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supporting information; experimental part
p. 2587 - 2591
(2011/04/12)
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- Amination of alcohols catalyzed by copper-aluminium Hydrotalcite: A green synthesis of amines
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Copper-aluminium hydrotalcite (CuAl-HT)/K2CO3 has been employed in the activation of various benzyl alcohols with benzylamines to afford the corresponding amines in good to high yields. Experimentation showed that the reaction takes place through sequential transformations: the oxidation of alcohols into carbonyl compounds, imine formation between amines and carbonyl compounds, and then reduction of imines to amines, heterogeneously catalyzed by non-noble Cu-Al HT catalyst in a one-pot and straightforward fashion. The process was further extended to amination of alcohols with anilines, which are often resistant to alkylation reactions when substituted with strong electron-withdrawing groups.
- Likhar, Pravin R.,Arundhathi, Racha,Kantam, Mannepalli Lakshmi,Prathima, Parvathaneni Sai
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experimental part
p. 5383 - 5389
(2010/02/28)
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- 1,2,3-Triazole-boranes: Stable and efficient reagents for ketone and aldehyde reductive amination in organic solvents or in water
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Air, moisture and thermally stable 1,2,3-triazole-borane complexes were developed as new practical reagents for ketone/aldehyde amination with high efficiency and excellent substrate diversity.
- Liao, Wenyan,Chen, Yunfeng,Liu, Yuxiu,Duan, Haifeng,Petersen, Jeffrey L.,Shi, Xiaodong
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supporting information; experimental part
p. 6436 - 6438
(2010/03/04)
-
- Allosteric functional switch of neurokinin A-mediated signaling at the neurokinin NK2 receptor: Structural exploration
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The neurokinin NK2 receptor is known to pre-exist in equilibrium between at least three states: restinginactive, calcium-triggering, and cAMP-producing. Its endogeneous ligand, NKA, mainly induces the calcium response. Using a FRET-based assay, we have previously discovered an allosteric modulator of the NK2 receptor that has the unique ability to discriminate among the two signaling pathways: calcium-signaling is not affected while cAMP signaling is significantly decreased. A series of compounds have been prepared and studied in order to better understand the structural determinants of this allosteric functional switch of a GPCR. Most of them display the same allosteric profile, with smooth pharmacomodulation. One compound however exhibits significantly improved modulatory properties of NKA induced signaling when compared to the original modulator. 2009 American Chemical Society.
- Valant, Céline,Maillet, Emeline,Bourguignon, Jean-Jacques,Bucher, Bernard,Utard, Valérie,Galzi, Jean-Luc,Hibert, Marcel
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experimental part
p. 5999 - 6011
(2010/03/24)
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- Secondary amines: Synthesis and effect of length of spacer linking two phenyl rings on biological activity
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N-Benzyl benzylamines (1a-11a) and N-benzyl anilines (1b-11b) were synthesized by sodium borohydride reduction of aldimines of benzylamine and aniline respectively. The products were characterized on the basis of elemental analysis and spectral studies and screened for antifungal potential against four fungi and evaluated for nematicidal activity against two nematodes. The former compounds were found to be more effective as compared to the latter thus indicating an enhancement of biological activity due to introduction of an extra methylene group between two phenyl rings of aromatic secondary amines.
- Rani, Neeraj,Sharma,Kaul,Manrao
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experimental part
p. 1041 - 1044
(2009/12/24)
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- Cp*Ir-catalyzed N-alkylation of amines with alcohols. A versatile and atom economical method for the synthesis of amines
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A versatile and highly atom economical catalytic system consisting of [Cp*IrCl2]2/NaHCO3 (Cp*=pentamethylcyclopentadienyl) for the N-alkylation of amines with primary and secondary alcohols as alkylating reagents has been developed. For example, the reaction of equimolar amounts of aniline and benzyl alcohol in the presence of [Cp*IrCl2]2 (1.0 mol % Ir) and NaHCO3 (1.0 mol %) in toluene at 110 °C gives N-benzylaniline in 94% yield. The present catalytic system is applicable to the N-alkylation of both primary and secondary amines, and only harmless water is produced as co-product. A wide variety of secondary and tertiary amines can be synthesized with high atom economy under mild and less-toxic conditions. One-pot sequential N-alkylation leading to tertiary amines bearing three different substituents is also described.
- Fujita, Ken-ichi,Enoki, Youichiro,Yamaguchi, Ryohei
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p. 1943 - 1954
(2008/09/17)
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- Effective reductive amination of carbonyl compounds with hydrogen catalyzed by iridium complex in organic solvent and in ionic liquid
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The direct reductive amination (DRA) of carbonyl compounds with amines has been achieved using homogenous iridium catalyst and gaseous hydrogen. It appeared that the cationic iridium catalyst, [Ir(cod)2]BF 4, without any other ligands was sufficient for the reaction. For the DRA of the ketone substrates, an ionic liquid, [Bmim]BF4, was found to be superior to the other organic solvent used. Especially, the counter anion of the ionic liquid has a significant influence on the selectivity, and at the same time, a high reaction temperature was found to be crucial for the excellent selectivity.
- Imao, Daisuke,Fujihara, Shoichiro,Yamamoto, Takeshi,Ohta, Tetsuo,Ito, Yoshihiko
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p. 6988 - 6992
(2007/10/03)
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- Oxidative N-debenzylation of N-benzyl-N-substituted benzylamines catalyzed by horseradish peroxidase
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A report on the oxidative N-debenzylation of N-benyl-N-substituted benzylamines catalyzed by horseradish peroxidase was presented. A solution of benzylamine in benzene was added to a benzene solution of p-anisaldehyde in 100 ml flask over 10 minutes. Expulsion of proton and hydroxylation yielding α-hydroxylamines were followed by the formation of benzaldehydes and benzylamines.
- Kim, Sung Soo,Jung, Hwan
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p. 555 - 558
(2007/10/03)
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- Efficient preparation of N-benzyl secondary amines via benzylamine-borane mediated reductive amination
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An efficient one-pot reductive amination protocol for preparing N-benzyl secondary amines is described.
- Peterson, Matt A.,Bowman, Adam,Morgan, Sarah
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p. 443 - 448
(2007/10/03)
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- Sodium borohydride-iodine, an efficient reagent for reductive amination of aromatic aldehydes
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Reactions of aromatic aldehydes with primary amines give the corresponding secondary amines in the presence of iodine and sodium borohydride in methanol.
- Saxena, Ira,Borah, Ruli,Sarma, Jadab C.
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p. 1970 - 1971
(2007/10/03)
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- Reductive amination of aromatic aldehydes and ketones with nickel boride
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The reductive amination of aromatic aldehydes and ketones with nickel boride was investigated. The reactions of aromatic aldehydes and ketones with primary amines produced corresponding secondary amines in the presence of in situ generated nickel boride. The secondary amines were found to remain inert in the system.
- Saxena, Ira,Borah, Ruli,Sarma, Jadab C.
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p. 503 - 504
(2007/10/03)
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- Use of polymer supported reagents for clean multi-step organic synthesis: Preparation of amines and amine derivatives from alcohols for use in compound library generation
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The automated sequential application of polymer supported perruthenate (PSP) and polymer supported cyanoborohydride (PSCBH) in an oxidation-reductive amination procedure allowed the efficient transformation of simple alcohols into more complex amines which can be further derivatised by the use of polymer bound amino sulfonylpyridinium chlorides.
- Ley, Steven V.,Bolli, Martin H.,Hinzen, Berthold,Gervois, Anne-Geraldine,Hall, Beverley J.
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p. 2239 - 2241
(2007/10/03)
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- EFFECTS OF SUBSTITUENTS IN THE BENZYL BROMIDE ON THE KINETICS OF THE BENZYLATION OF AMINES
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The kinetics of the reactions of 3- and 4-substituted benzyl bromides with amines having various structures in nitrobenzene at 40 deg C were investigated.The 4-substituted benzyl bromides have higher reactivity compared with that calculated on the basis of the linear correlations according to the Hammett-Taft equation for unsubstituted and 3-substituted benzyl bromides containing electron-withdrawning substituents.The reactivity of benzyl bromides containing electron-donating substituents obeys a linear correlation with the ?+ constants.The effects of structural changes in the substrate and the nucleophile on the character of the transition states of the investigated reactions is discussed.
- Shpan'ko, I. V.,Korostylev, A. P.,Rusu, L. N.
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p. 1715 - 1723
(2007/10/02)
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- CHEMICAL INDUCTION OF POLY-CIS CAROTENOID BIOSYNTHESIS
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Key Word Index - Citrus paradisi; Rutaceae; Marsh white seedless grapefruit; carotenoid biosynthesis; bioregulators; poly-cis carotenoids; carotenoids; prolycopene.A new class of synthetic bioregulators is reported which cause the accumulation of poly-cis carotenoids in the flavedo of Marsh white seedless grapefruit.The compounds tested were all secondary amines: dibenzylamine, substituted dibenzylamines (4-F; 4-Cl; 4-Br; 2-, 3- and 4-Me; 4-NO2; 4-CN; 4-Cl; 4'-Me; 4-Me, 4'-NO2), N-benzyl phenethylamine and N-benzyl 2-naphthalenemethylamine.The most effective, 4-chlorodibenzylamine, caused the accumulation of 74 μg/g dry wt of poly-cis carotenoids.Prolycopene was the predominant pigment but substantial amounts of proneurosporene, poly-cis-γ-carotenes and other cis carotenes were also present.The mode of action of these new bioregulators is probably gene derepression, the same as that of the lycopene inducers.However, the secondary amines probably derepress a recessive gene governing the biosynthesis of poly-cis carotenoids; whereas, the lycopene inducers derepress the dominant gene that gives rise to the normall all-trans carotenoids.The new compounds did not seem to inhibit the cyclase(s), as the lycopene inducers do.
- Poling, Stephen M.,Hsu, Wan-Jean,Yokoyama, Henry
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p. 1677 - 1680
(2007/10/02)
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