- One pot catalytic NO2 reduction, ring hydrogenation, and N-alkylation from nitroarenes to generate alicyclic amines using Ru/C-NaNO 2
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A report to produce alicyclic amines and subsequent N-alkylation with alcohols using Ru/C-NaNO2 catalyzed facile transformation of nitrobenzene was investigated. Effects of solvent, temperature, pressure, reaction time, and molar-ratio of substrate/catalyst on product composition were also studied. These mechanistic studies explain that nitrobenzene undergoes hydrogenation reaction in the following order; -NO2 reduction to -NH2, aromatic ring-hydrogenation to alicyclic, and from the reaction of alcohol to give N-alkylated amines. This investigation shed lights on possible application to polyurethane chemistry since these amines are used as important precursors for diisocyanates.
- Oh, Seung Geun,Mishra, Vivek,Cho, Jin Ku,Kim, Baek-Jin,Kim, Hoon Sik,Suh, Young-Woong,Lee, Hyunjoo,Park, Ho Seok,Kim, Yong Jin
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- Reductive N-methylation of amines with calcium hydride and Pd/C catalyst
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The methylation of amines by paraformaldehyde in the presence of calcium hydride as a source of hydrogen and palladium on charcoal as catalyst was studied. Depending on the quantity of paraformaldehyde, monomethylated and dimethylated amines were selectively and efficiently prepared in one pot with good yields.
- Guyon, Carole,Duclos, Marie-Christine,Métay, Estelle,Lemaire, Marc
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- Commercial Pd/C-Catalyzed N-Methylation of Nitroarenes and Amines Using Methanol as Both C1 and H2 Source
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Herein, we report commercially available carbon-supported-palladium (Pd/C)-catalyzed N-methylation of nitroarenes and amines using MeOH as both a C1 and a H2 source. This transformation proceeds with high atom-economy and in an environmentally friendly way via borrowing hydrogen mechanism. A total of >30 structurally diverse N-methylamines, including bioactive compounds, were selectively synthesized with isolated yields of up to 95%. Furthermore, selective N-methylation and deuteration of nimesulide, a nonsteroidal anti-inflammatory drug, were realized through the late-stage functionalization.
- Goyal, Vishakha,Gahtori, Jyoti,Narani, Anand,Gupta, Piyush,Bordoloi, Ankur,Natte, Kishore
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- Zinc-promoted, iridium catalyzed reductive alkylation of primary amines with aliphatic ketones in aqueous medium
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The reductive alkylation of primary aromatic and aliphatic amines with aliphatic ketones has been achieved in aqueous acidic medium using commercially available, non-activated zinc dust catalyzed by a very small quantity of iridium bromide. Anilines react well in aqueous formic acid, whereas monoalkylamines require 1,4-dioxane as a co-solvent and sulfuric acid as the proton source. A plausible mechanism via low-valent iridium hydride species is proposed.
- da Silva, Renato A.,Bieber, Lothar W.
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- Dual pathways for the desilylation of silylamines by singlet oxygen
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A kinetic and product study has been carried out for the reactions of silylamines 1a and 1b with 1O2 in MeCN and (80:20) MeCN-MeOH. Indications suggesting an electron-transfer step following exciplex (I) formation have been obtained. However, the fate of the radical cation is solvent dependent. The radical cation undergoes desilylation in MeCN-MeOH and deprotonation in MeCN.
- Baciocchi, Enrico,Del Giacco, Tiziana,Lapi, Andrea
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- Dichlorobis(1,4-diazabicyclo[2.2.2]octane)(tetrahydroborato)zirco- nium(IV), [Zr(BH4)2Cl2(dabco)2](ZrBDC), as a new, stable, and versatile bench top reducing agent: Reduction of imines and enamines, reductive amination of aldehydes and ketones and reductive methylation of amines
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The reducing agent is easily prepared in an almost quantitative yield from commercially available starting materials. This compound is stable under mild aqueous acidic conditions (pH 4-6) and survives in H2O for several days without losing its reducing abilities. ZrBDC has been successfully used for the reduction of imines and enamines, reductive amination of aldehydes and ketones, and reductive methylation of amines.
- Firouzabadi, Habib,Iranpoor, Nasser,Alinezhad, Heshmatollah
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- Identification of Novel Bacterial Members of the Imine Reductase Enzyme Family that Perform Reductive Amination
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Reductive amination of carbonyl compounds constitutes one of the most efficient ways to rapidly construct chiral and achiral amine frameworks. Imine reductase (IRED) biocatalysts represent a versatile family of enzymes for amine synthesis through NADPH-mediated imine reduction. The reductive aminases (RedAms) are a subfamily of IREDs that were recently shown to catalyze imine formation as well as imine reduction. Herein, a diverse library of novel enzymes were expressed and screened as cell-free lysates for their ability to facilitate reductive amination to expand the known suite of biocatalysts for this transformation and to identify more enzymes with potential industrial applications. A range of ketones and amines were examined, and enzymes were identified that were capable of accepting benzylamine, pyrrolidine, ammonia, and aniline. Amine equivalents as low as 2.5 were employed to afford up to >99 % conversion, and for chiral products, up to >98 % ee could be achieved. Preparative-scale reactions were conducted with low amine equivalents (1.5 or 2.0) of methylamine, allylamine, and pyrrolidine, achieving up to >99 % conversion and 76 % yield.
- France, Scott P.,Howard, Roger M.,Steflik, Jeremy,Weise, Nicholas J.,Mangas-Sanchez, Juan,Montgomery, Sarah L.,Crook, Robert,Kumar, Rajesh,Turner, Nicholas J.
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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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- Electrocatalytic Dealkylation of Amines Mediated by Ferrocene
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The homogeneous catalytic oxidation of dicyclohexylamine (DCHA), N,N-dimethylcyclohexylamine (DMCHA) and N,N-dicyclohexylmethylamine (DCHMA) has been investigated in the presence of electrochemically generated ferrocenium ions as the catalyst. Mechanistic details for this electrocatalytic process have been scrutinized with the use of cyclic voltammetry, bulk electrolysis, and digital simulations techniques. A one-electron catalytic process between ferrocene and the respective amines was observed. The products obtained from bulk electrolysis were isolated and identified by FTIR, 1H and 13C NMR spectroscopy, and mass spectrometry. Both DCHMA and DMCHA proceed to yield a secondary amine product by the elimination of one methyl group. In the absence of this group, as in the case of DCHA, the cycloalkyl group is then eliminated. The catalytic efficiency and the second-order rate constants were estimated and found to follow the order DCHA ≤ DMCHA DCHMA. The results presented in this work should open up a new avenue to achieve simple, low-cost, and efficient amine oxidation, which could be useful in several areas of chemistry.
- Torriero, Angel A. J.,Morda, Joanne,Saw, Jessica
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- Catalytic reduction of the arene ring, and other functionalities, of organic substrates using formic acid and palladium on carbon
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The arene ring in a variety of compounds with functionalities which contain nitrogen is reduced in good yields using formic acid and Pd/C in methanol.
- Alper, Howard,Vampollo, Guiseppe
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- Simple RuCl3-catalyzed N-Methylation of Amines and Transfer Hydrogenation of Nitroarenes using Methanol
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Methanol is a potential hydrogen source and C1 synthon, which finds interesting applications in both chemical synthesis and energy technologies. The effective utilization of this simple alcohol in organic synthesis is of central importance and attracts scientific interest. Herein, we report a clean and cost-competitive method with the use of methanol as both C1 synthon and H2 source for selective N-methylation of amines by employing relatively cheap RuCl3.xH2O as a ligand-free catalyst. This readily available catalyst tolerates various amines comprising electron-deficient and electron-donating groups and allows them to transform into corresponding N-methylated products in moderate to excellent yields. In addition, few marketed pharmaceutical agents (e. g., venlafaxine and imipramine) were also successfully synthesized via late-stage functionalization from readily available feedstock chemicals, highlighting synthetic value of this advanced N-methylation reaction. Using this platform, we also attempted tandem reactions with selected nitroarenes to convert them into corresponding N-methylated amines using MeOH under H2-free conditions including transfer hydrogenation of nitroarenes-to-anilines and prepared drug molecules (e. g., benzocaine and butamben) as well as key pharmaceutical intermediates. We further enable one-shot selective and green syntheses of 1-methylbenzimidazole using ortho-phenylenediamine (OPDA) and methanol as coupling partners.
- Sarki, Naina,Goyal, Vishakha,Tyagi, Nitin Kumar,Puttaswamy,Narani, Anand,Ray, Anjan,Natte, Kishore
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- A New and Specific Method for the Monomethylation of Primary Amines
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The reduction of monomeric methyleneamines, representing a convenient and highly specific procedure for the title reaction, is studied.
- Barluenga, Jose,Bayon, Ana M.,Asensio, Gregorio
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- Quenching of singlet oxygen by tertiary aliphatic amines. Structural effects on rates and products
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A kinetic and product study of the reaction of a series of α-methyl-substituted N-methylpiperidines with thermally generated 1O2 in MeCN was carried out. It was found that as the number of α-methyl groups (Me in α-position relative to the N-atom) increases, the rate of 1O2 quenching (physical plus chemical) slightly decreases. This finding shows that, with respect to the reaction rate, steric effects are much more important than electronic effects as the latter should have produced the opposite result. The opposite outcome was instead found for the chemical quenching that leads to the N-demethylation products and N-formyl derivatives. The same trend was observed for the ratio between N-demethylation and formation of the N-formyl derivatives (NH/NCHO ratio). All these results are consistent with the mechanism reported in Scheme 1 where an exciplex is first formed that by a H-atom transfer process produces an α-amino-substituted C-radical. The latter forms the product of N-demethylation by one electron oxidation, or affords the N-formyl derivative by radical coupling (Scheme 1). Similar results were obtained with N,N-dimethylcyclohexanamine. However, this 'acyclic' amine exhibited behaviors quite distinct from those of the N-methylpiperidines series, with respect to reaction rate, extent of chemical quenching, and NH/NCHO ratio.
- Baciocchi, Enrico,Del Giacco, Tiziana,Lapi, Andrea
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- Mechanistic Studies on the Role of Carbon Dioxide in the Synthesis of Methylcarbamates from Amines and Dimethylcarbonate in the Presence of CO2
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N-Alkylmethylcarbamates have been synthesized from amines and dimethylcarbonate (DMC) in the presence of carbon dioxide.The catalytic role of CO2 in the overall process has been investigated and elucidated.Key words: carbon dioxide; organic carbamates; dimethylcarbonate; carbamic-carbonic anhydride
- Aresta, Michele,Quaranta, Eugenio
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- Rhenium-Loaded TiO2: A Highly Versatile and Chemoselective Catalyst for the Hydrogenation of Carboxylic Acid Derivatives and the N-Methylation of Amines Using H2 and CO2
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Herein, we report a heterogeneous TiO2-supported Re catalyst (Re/TiO2) that promotes various selective hydrogenation reactions, which includes the hydrogenation of esters to alcohols, the hydrogenation of amides to amines, and the N-methylation of amines, by using H2 and CO2. Initially, Re/TiO2 was evaluated in the context of the selective hydrogenation of 3-phenylpropionic acid methyl ester to afford 3-phenylpropanol (pH2 =5 MPa, =5 MPa, T=180 °C), which revealed a superior performance over other catalysts that we tested in this study. In contrast to other typical heterogeneous catalysts, hydrogenation reactions with Re/TiO2 did not produce dearomatized byproducts. DFT studies suggested that the high selectivity for the formation of alcohols in favor of the hydrogenation of aromatic rings is ascribed to the higher affinity of Re towards the COOCH3 group than to the benzene ring. Moreover, Re/TiO2 showed a wide substrate scope for the hydrogenation reaction (19 examples). Subsequently, this Re/TiO2 catalyst was applied to the hydrogenation of amides, the N-methylation of amines, and the N-alkylation of amines with carboxylic acids or esters.
- Toyao, Takashi,Siddiki,Morita, Yoshitsugu,Kamachi, Takashi,Touchy, Abeda S.,Onodera, Wataru,Kon, Kenichi,Furukawa, Shinya,Ariga, Hiroko,Asakura, Kiyotaka,Yoshizawa, Kazunari,Shimizu, Ken-Ichi
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- Synthesis of methyl carbamates from primary aliphatic amines and dimethyl carbonate in supercritical CO2: Effects of pressure and cosolvents and chemoselectivity
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(Chemical Equation Presented) At 130 °C, in the presence of CO 2 (5-200 bar), primary aliphatic amines react with dimethyl carbonate (MeOCO2Me, DMC) to yield methyl carbamates (RNHCO2Me) and N-methylation side-products (RNHMe and RNMe2). The pressure of CO2 largely influences both the reaction conversion and the selectivity toward urethanes: in general, conversion goes through a maximum (70-80%) in the midrange (40 bar) and drops at lower and higher pressures, whereas selectivity is continuously improved (from 50% up to 90%) by an increase of the pressure. This is explained by the multiple role of CO2 in (i) the acid/base equilibrium with aliphatic amines, (ii) the reactivity/solubility of RNHCO2- nucleophiles with/in DMC, and (iii) the inhibition of competitive N-methylation reaction of the substrates. Cosolvents also affect the reaction: in particular, a drop in selectivity is observed with polar protic media (i.e., MeOH), plausibly because of solvation effects (through H-bonds) of RNHCO2- moieties. The reaction shows also a good chemoselectivity: bifunctional aliphatic amines bearing either aromatic NH2 or OH substituents [XC6H4(CH2)nNH2, X = NH2, OH; n = 1 2], undergo methoxycarbonylation reactions exclusively at aliphatic amino groups and give the corresponding methyl carbamates [XC 6H4(CH2)nNHCO2Me] in 39-65% isolated yields.
- Selva, Maurizio,Tundo, Pietro,Perosa, Alvise,Dall'Acqua, Federico
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- Direct Alkylation of Amines with Primary and Secondary Alcohols through Biocatalytic Hydrogen Borrowing
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The reductive aminase from Aspergillus oryzae (AspRedAm) was combined with a single alcohol dehydrogenase (either metagenomic ADH-150, an ADH from Sphingobium yanoikuyae (SyADH), or a variant of the ADH from Thermoanaerobacter ethanolicus (TeSADH W110A)) in a redox-neutral cascade for the biocatalytic alkylation of amines using primary and secondary alcohols. Aliphatic and aromatic secondary amines were obtained in up to 99 % conversion, as well as chiral amines directly from the racemic alcohol precursors in up to >97 % ee, releasing water as the only byproduct.
- Montgomery, Sarah L.,Mangas-Sanchez, Juan,Thompson, Matthew P.,Aleku, Godwin A.,Dominguez, Beatriz,Turner, Nicholas J.
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- Fluoride-Catalyzed Methylation of Amines by Reductive Functionalization of CO2with Hydrosilanes
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An effective and inexpensive organocatalyst tetrabutylammonium fluoride (TBAF) was developed for the reductive functionalization of CO2with amines to selectively afford formamides or methylamines by employing hydrosilanes. Hydrosilanes with different substituents show discriminatory reducing activity. Thus, the formation of formamides and further reduction products, that is, methylamines could be controlled by elegantly tuning hydrosilane types. Formamides were obtained exclusively under an atmospheric pressure of CO2with triethoxysilane. Using phenylsilane as a reductant, methylamines were attained with up to 99 % yield at 50 °C coupled to a complete deoxygenation of CO2. The crucial intermediate silyl formate in the formylation step was identified and thereby a tentative mechanism involving the fluoride-promoted hydride transfer from the hydrosilane to CO2/formamide was proposed. Striking features of this metal-free protocol are formylation and methylation of amines by reductive functionalization of CO2with hydrosilanes and mild reaction conditions.
- Liu, Xiao-Fang,Ma, Ran,Qiao, Chang,Cao, Han,He, Liang-Nian
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- Transition Metal-catalysed N-Alkylation of Amines by Alcohols
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Primary and secondary alcohols effect alkylation of primary and secondary amines in the presence of rhodium, iridium, and ruthenium compounds at = 100 deg C, whereby selective monoalkylation of primary amines can be achieved, and heterocyclic rings can be constructed by both inter- and intra-molecular processes.
- Grigg, R.,Mitchell, T. R. B.,Sutthivaiyakit, S.,Tongpenyai, N.
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- Katalytische C-C- und C-N-Kupplungsreaktionen von Carbodiimiden durch Uebergangsmetallcluster
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N,N'-Dialkyl carbodiimides react with hydrogen in the presence of ruthenium clusters to give new N,N',N''-trialkyl guanidines.The reaction with terminal acetylenes, catalyzed by a bimetallic cluster system, leads to new N,N'-dialkyl propiolamidines.
- Schmidt, Gerhard F.,Suess-Fink, Georg
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- Continuous reductions and reductive aminations using solid NaBH4
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Most successful reactions carried out under continuous flow conditions mix homogeneous solutions yielding homogeneous products. Using solids is avoided to prevent pump and reactor clogging; even though solid reagents may often be the best choice for a given transformation. Here we demonstrate that by pumping aldehydes, ketones, or in situ formed imines through a specially formulated NaBH4 column results in efficient reductions. The column design and performance characteristics, along with substrate scope, are discussed.
- Gilmore, Kerry,Vukeli, Stella,McQuade, D. Tyler,Koksch, Beate,Seeberger, Peter H.
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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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- Photon-initiated heterogeneous redox couples for methylation of anilines under mild conditions
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Methylation of anilines has drawn a lot of attention due to their valuable applications and directly using methanol as a methylation reagent is of great advantage. Photon-initiated heterogeneous catalysis of this methylation process meets the requirements of green chemistry. Herein we show that balanced redox zones within carbon nitride supported Pd nanoparticles boost the selectivity of methylation of anilines under mild conditions.
- Zhang, Bing,Gao, Hua,Wang, Wei
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- Ruthenium Catalyzed N-Methylation of Aminoarenes Using Methanol
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Methanol reacts with aminoarenes in the presence of a catalytic amount of ruthenium trichloride hydrate combined with tributylphosphite at 180 deg C to give the corresponding N-methylaminoarenes in high yields.
- Huh, Keun-Tae,Tsuji, Yasushi,Kobayashi, Masanobu,Okuda, Fumio,Watanabe, Yoshihisa
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- AlCl3 immobilized on silicic acid as efficient Lewis acid catalyst for highly selective preparation of dicyclohexylamine from the vapor phase hydroamination of cyclohexene with cyclohexylamine
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An efficient and stable Lewis acid catalyst silicic acid (SA)-immobilized AlCl3 (AlCl3-SA) has been successfully prepared by the chemical bonding method in this work. The results indicated that the immobilized 15percentAlCl3-SA exhibited excellent catalytic performance and stability in the vapor phase hydroamination of cyclohexene with cyclohexylamine. 58.5percent cyclohexene conversion with 98.7percent selectivity to dicyclohexylamine was still maintained after running for over 150 h, and the space time yield of dicyclohexylamine was 142.6 mol/h·m3. The developed AlCl3-SA catalyst had the advantages of low cost and long-time stable activity. Maybe this work provides a promising approach for hydroamination of olefins to amines.
- Ai, Qiuhong,Jian, Jian,Liu, Pingle,Luo, He'an,Wen, Jingbin,You, Kuiyi,Zhao, Fangfang
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- tert-Butoxy-Radical-Promoted α-Arylation of Alkylamines with Aryl Halides
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In the presence of a tert-butoxy radical precursor, the reaction of alkylamines with aryl halides was found to give α-arylated alkylamines through homolytic aromatic substitution of the halogen atoms.
- Ueno, Ryota,Ikeda, Yuko,Shirakawa, Eiji
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- N-Methylation of amines and nitroarenes with methanol using heterogeneous platinum catalysts
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We report herein the selective N-methylation of amines and nitroarenes with methanol under basic conditions using carbon-supported Pt nanoparticles (Pt/C) as a heterogeneous catalyst. This method is widely applicable to four types of N-methylation reactions: (1) N,N-dimethylation of aliphatic amines under N2, (2) N-monomethylation of aliphatic amines under 40 bar H2, (3) N-monomethylation of aromatic amines under N2, and (4) tandem synthesis of N-methyl anilines from nitroarenes and methanol under 2 bar H2. All these reactions under the same catalytic system showed high yields of the corresponding methylamines for a wide range of substrates, high turnover number (TON), and good catalyst reusability. Mechanistic studies suggested that the reaction proceeded via a borrowing hydrogen methodology. Kinetic results combined with density functional theory (DFT) calculations revealed that the high performance of Pt/C was ascribed to the moderate metal–hydrogen bond strength of Pt.
- Jamil, Md.A.R.,Touchy, Abeda S.,Rashed, Md. Nurnobi,Ting, Kah Wei,Siddiki, S.M.A. Hakim,Toyao, Takashi,Maeno, Zen,Shimizu, Ken-ichi
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- Electronically tuneable orthometalated RuII–NHC complexes as efficient catalysts for C–C and C–N bond formations via borrowing hydrogen strategy
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The catalytic activities of a series of simple and electronically tuneable cyclometalated RuII–NHC complexes (2a–d) were explored in various C–C/N bond formations following the borrowing hydrogen process. Slight modifications in the ligand backbone were noted to tune the activities of these complexes. Among them, the complex 2d featuring a 1,2,4-triazolylidene donor with a 4-NO2–phenyl substituent displayed the highest activity for the coupling of diverse secondary and primary alcohols with a low catalyst loading of 0.01 mol% and a sub-stoichiometric amount of inexpensive KOH base. The efficacy of this simple system was further showcased in the challenging one-pot unsymmetrical double alkylation of secondary alcohols using different primary alcohols. Moreover, the complex 2d also effectively catalyses the selective mono-N-methylation of various aromatic and aliphatic primary amines using methanol to deliver a range of N-methyl amines. Mechanistically, the β-alkylation reaction follows a borrowing hydrogen pathway which was established by the deuterium labelling experiment in combination with various control experiments. Intriguingly, in situ1H NMR and ESI-MS analyses evidently suggested the involvement of a Ru–H species in the catalytic cycle and further, the kinetic studies revealed a first order dependence of the reaction rate on the catalyst as well as the alcohol concentrations.
- Illam, Praseetha Mathoor,Rit, Arnab
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- Fe3O4@GlcA@Cu-MOF: A Magnetic Metal-Organic Framework as a Recoverable Catalyst for the Hydration of Nitriles and Reduction of Isothiocyanates, Isocyanates, and Isocyanides
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A novel magnetic metal-organic framework (Fe3O4@GlcA@Cu-MOF) has been prepared and characterized by spectroscopic, microscopic, and magnetic techniques. This magnetically separable catalyst exhibited high catalytic activity for nitrile hydration and the ability to reduce isothiocyanates, isocyanates, and isocyanides with excellent activity and selectivity without any additional reducing agent.
- Ghorbani-Choghamarani, Arash,Taherinia, Zahra
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supporting information
p. 902 - 909
(2020/11/30)
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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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- Cobalt-Nanoparticles Catalyzed Efficient and Selective Hydrogenation of Aromatic Hydrocarbons
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The development of inexpensive and practical catalysts for arene hydrogenations is key for future valorizations of this general feedstock. Here, we report the development of cobalt nanoparticles supported on silica as selective and general catalysts for such reactions. The specific nanoparticles were prepared by assembling cobalt-pyromellitic acid-piperazine coordination polymer on commercial silica and subsequent pyrolysis. Applying the optimal nanocatalyst, industrial bulk, substituted, and functionalized arenes as well as polycyclic aromatic hydrocarbons are selectively hydrogenated to obtain cyclohexane-based compounds under industrially viable and scalable conditions. The applicability of this hydrogenation methodology is presented for the storage of H2 in liquid organic hydrogen carriers.
- Murugesan, Kathiravan,Senthamarai, Thirusangumurugan,Alshammari, Ahmad S.,Altamimi, Rashid M.,Kreyenschulte, Carsten,Pohl, Marga-Martina,Lund, Henrik,Jagadeesh, Rajenahally V.,Beller, Matthias
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p. 8581 - 8591
(2019/09/12)
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- SMALL MOLECULE ACTIVATORS OF NICOTINAMIDE PHOSPHORIBOSYLTRANSFERASE (NAMPT) AND USES THEREOF
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Provided herein are small molecule activators of Nicotinamide Phosphoribosyltransferase (NAMPT), compositions comprising the compounds, and methods of using the compounds and compositions.
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Paragraph 00498
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- Methylation of Cycloalkanamines with Dimethyl Carbonate in the Presence of Binder-Free NaY Zeolite
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N-Methyl- and N,N-dimethylcycloalkanamines were synthesized by reaction of cycloalkanamines with dimethyl carbonate in the presence of NaY zeolite containing no binder. Optimal reactant and catalyst ratios and reaction conditions were found.
- Khusnutdinov,Shchadneva,Mayakova, Yu. Yu.,Egorova,Khazipova,Kutepov
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p. 654 - 656
(2018/06/13)
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- Selective Monomethylation of Amines with Methanol as the C1 Source
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The N-monomethyl functionality is a common motif in a variety of synthetic and natural compounds. However, facile access to such compounds remains a fundamental challenge in organic synthesis owing to selectivity issues caused by overmethylation. To address this issue, we have developed a method for the selective, catalytic monomethylation of various structurally and functionally diverse amines, including typically problematic primary aliphatic amines, using methanol as the methylating agent, which is a sustainable chemical feedstock. Kinetic control of the aliphatic amine monomethylation was achieved by using a readily available ruthenium catalyst at an adequate temperature under hydrogen pressure. Various substrates including bio-related molecules and pharmaceuticals were selectively monomethylated, demonstrating the general utility of the developed method.
- Choi, Geunho,Hong, Soon Hyeok
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supporting information
p. 6166 - 6170
(2018/04/30)
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- Efficient and versatile catalytic systems for the n-methylation of primary amines with methanol catalyzed by n-heterocyclic carbene complexes of iridium
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Efficient and versatile catalytic systems were developed for the N-methylation of both aliphatic and aromatic primary amines using methanol as the methylating agent. Iridium complexes bearing an Nheterocyclic carbene (NHC) ligand exhibited high catalytic performance for this type of transformation. For aliphatic amines, selective N,N-dimethylation was achieved at low temperatures (50-90 °C). For aromatic amines, selective N-monomethylation and selective N,N-dimethylation were accomplished by simply changing the reaction conditions (presence or absence of a base with an appropriate catalyst). These findings can be used to develop methods for synthesizing useful amine compounds having N-methyl or N,N-dimethyl moieties.
- Toyooka, Genki,Tuji, Akiko,Fujita, Ken-Ichi
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p. 4617 - 4626
(2019/02/01)
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- Photometric Characterization of the Reductive Amination Scope of the Imine Reductases from Streptomyces tsukubaensis and Streptomyces ipomoeae
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Imine reductases (IREDs) have emerged as promising enzymes for the asymmetric synthesis of secondary and tertiary amines starting from carbonyl substrates. Screening the substrate specificity of the reductive amination reaction is usually performed by time-consuming GC analytics. We found two highly active IREDs in our enzyme collection, IR-20 from Streptomyces tsukubaensis and IR-Sip from Streptomyces ipomoeae, that allowed a comprehensive substrate screening with a photometric NADPH assay. We screened 39 carbonyl substrates combined with 17 amines as nucleophiles. Activity data from 663 combinations provided a clear picture about substrate specificity and capabilities in the reductive amination of these enzymes. Besides aliphatic aldehydes, the IREDs accepted various cyclic (C4–C8) and acyclic ketones, preferentially with methylamine. IR-Sip also accepted a range of primary and secondary amines as nucleophiles. In biocatalytic reactions, IR-Sip converted (R)-3-methylcyclohexanone with dimethylamine or pyrrolidine with high diastereoselectivity (>94–96 % de). The nucleophile acceptor spectrum depended on the carbonyl substrate employed. The conversion of well-accepted substrates could also be detected if crude lysates were employed as the enzyme source.
- Matzel, Philipp,Krautschick, Lukas,H?hne, Matthias
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p. 2022 - 2027
(2017/10/07)
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- A biocatalytic cascade for the amination of unfunctionalised cycloalkanes
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Here we describe a one-pot, three-enzyme, cascade involving a cytochrome P450 monooxygenase, an alcohol dehydrogenase and a reductive aminase for the synthesis of secondary amines from cycloalkanes. Amine product concentrations of up to 19.6 mM were achieved. The preparative scale amination of cyclohexane was also demonstrated with a space-time yield of 2 g L-1 d-1.
- Tavanti, Michele,Mangas-Sanchez, Juan,Montgomery, Sarah L.,Thompson, Matthew P.,Turner, Nicholas J.
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supporting information
p. 9790 - 9793
(2017/12/08)
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- N -Monomethylation of amines using paraformaldehyde and H2
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The selective N-monomethylation of amines is an important topic in fine chemical synthesis. Herein, for the first time, we described a selective N-monomethylation reaction of amines with paraformaldehyde and H2 in the presence of a CuAlOx catalyst. A variety of amines, including primary aromatic amines, benzylamine and cyclohexylamine, as well as secondary amines, have been shown to be compatible with this reaction.
- Wang, Hongli,Huang, Yongji,Dai, Xingchao,Shi, Feng
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supporting information
p. 5542 - 5545
(2017/07/06)
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- Single-Site Cobalt Catalysts at New Zr12(μ3-O)8(μ3-OH)8(μ2-OH)6 Metal-Organic Framework Nodes for Highly Active Hydrogenation of Nitroarenes, Nitriles, and Isocyanides
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We report here the synthesis of a robust and porous metal-organic framework (MOF), Zr12-TPDC, constructed from triphenyldicarboxylic acid (H2TPDC) and an unprecedented Zr12 secondary building unit (SBU): Zr12(μ3-O)8(μ3-OH)8(μ2-OH)6. The Zr12-SBU can be viewed as an inorganic node dimerized from two commonly observed Zr6 clusters via six μ2-OH groups. The metalation of Zr12-TPDC SBUs with CoCl2 followed by treatment with NaBEt3H afforded a highly active and reusable solid Zr12-TPDC-Co catalyst for the hydrogenation of nitroarenes, nitriles, and isocyanides to corresponding amines with excellent activity and selectivity. This work highlights the opportunity in designing novel MOF-supported single-site solid catalysts by tuning the electronic and steric properties of the SBUs.
- Ji, Pengfei,Manna, Kuntal,Lin, Zekai,Feng, Xuanyu,Urban, Ania,Song, Yang,Lin, Wenbin
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p. 7004 - 7011
(2017/05/31)
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- Method for selectively preparing N-monomethylamine compound
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The invention discloses a method for selectively preparing an N-monomethylamine compound. The method takes an amine compound, formaldehyde and H2 as reaction raw materials; the raw materials react in a reaction medium in the presence of a compound catalyst at 30 DEG C-180 DEG C for 2h-48h, so as to obtain the N-monomethylamine compound; and the compound catalyst is composed of oxides of at least two of the following metal or oxides of least one of the following metal and at least one metal simple substance: aluminum, copper, nickel, cobalt and iron. According to the method for preparing the N-monomethylamine compound, the conversion ratio and the selectivity of N-monomethylamine are relatively high; the H2 is used as a reducing agent and is clean, cheap and environment-friendly; the catalyst utilized by the method is cheap, simple to prepare and high in catalysis efficiency; and the method has mild preparation and reaction conditions and the catalyst has no corrosiveness, is easy to separate and can be repeatedly used.
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Paragraph 0032-0033
(2017/08/29)
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- Asymmetric Reductive Amination of Ketones Catalyzed by Imine Reductases
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Biocatalysis employing imine reductases is a promising approach for the one-step generation of chiral amines from ketones. The enzymes reported for this process suffer from low activity and moderate stereoselectivity. We identified a set of enzymes that facilitate this reaction with high to quantitative conversions from a library of 28 imine reductases. This enabled the conversion of ketones with ammonia, methylamine, or butylamine into the corresponding amines. Most importantly, we performed preparative (>100 mg) scale syntheses of amines such as (1S,3R)-N,3-dimethylcyclohexylamine and (R)-N-methyl-2-aminohexane with excellent stereochemical purities (98 % de, 96 % ee) in good yields.
- Wetzl, Dennis,Gand, Martin,Ross, Alfred,Müller, Hubertus,Matzel, Philipp,Hanlon, Steven P.,Müller, Michael,Wirz, Beat,H?hne, Matthias,Iding, Hans
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p. 2023 - 2026
(2016/07/07)
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- Selective N-methylation of aliphatic amines with CO2 and hydrosilanes using nickel-phosphine catalysts
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A method using CO2 and PhSiH3 for the methylation of primary and secondary aliphatic amines catalyzed by Ni (0) complexes was developed, selectively producing the monomethylated products in moderate to good yields. For that purpose, two catalysts were used: [(dippe)Ni(μ-H)]2 and the commercially available Ni(COD)2/dcype, both of which were rather efficient in this process. With a slight experimental modification, the reaction allowed the production of monomethylated ureas in good yields by using low amounts of PhSiH3. On the basis of the experimental results, we propose a possible reaction mechanism for the formation of the new C-N bond.
- Gonzlez-Sebastin, Lucero,Flores-Alamo, Marcos,Garca, Juventino J.
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p. 763 - 769
(2015/05/12)
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- Catalytic hydrogenation of amides to amines under mild conditions
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Under (not so much) pressure: A general method for the hydrogenation of tertiary and secondary amides to amines with excellent selectivity using a bimetallic Pd-Re catalyst has been developed. The reaction proceeds under low pressure and comparatively low temperature. This method provides organic chemists with a simple and reliable tool for the synthesis of amines. Copyright
- Stein, Mario,Breit, Bernhard
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supporting information
p. 2231 - 2234
(2013/03/28)
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- A novel method for N-alkylation of aliphatic amines with ethers over ?3-Al2O3
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A novel and simple method for the N-alkylation of amines with different ethers as alkylating reagents has been developed, using cheap ?3-Al2O3 as the catalyst at atmospheric pressure in the temperature range of 260-320?°C. For example, the reaction of equ
- Chen, Hangeng,Zhang, Tao,Qian, Chao,Chen, Xinzhi
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p. 537 - 540
(2015/03/05)
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- PROCESS FOR PREPARING AN AMINE
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A process for preparing an amine by reacting an aldehyde and/or ketone with hydrogen and a nitrogen compound selected from the group of primary and secondary amines in the presence of a heterogeneous catalyst, wherein the catalyst is a coated catalyst which comprises at least one metal of group VIII of the Periodic Table of the Elements as a hydrogenating metal and additionally a promoter on an oxidic support, at least 80% of the metal of group VIII of the Periodic Table of the Elements being present in a layer between the surface of the catalyst and a penetration depth which is not more than 80% of the radius of the catalyst, calculated from the surface of the catalyst.
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Page/Page column 8-9
(2009/04/24)
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- Mechanism of formation of organic carbonates from aliphatic alcohols and carbon dioxide under mild conditions promoted by carbodiimides. DFT calculation and experimental study
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Dicyclohexylcarbodiimide (CyN=C=NCy, DCC) promotes the facile formation of organic carbonates from aliphatic alcohols and carbon dioxide at temperatures as low as 310 K and moderate pressure of CO2 (from 0.1 MPa) with an acceptable rate. The conversion yield of DCC is quantitative, and the reaction has a very high selectivity toward carbonates at 330 K; increasing the temperature increases the conversion rate, but lowers the selectivity. A detailed study has allowed us to isolate or identify the intermediates formed in the reaction of an alcohol with DCC in the presence or absence of carbon dioxide. The first step is the addition of alcohol to the cumulene (a known reaction) with formation of an O-alkyl isourea [RHNC(ORO=NR] that may interact with a second alcohol molecule via H-bond (a reaction never described thus far). Such an adduct can be detected by NMR. In alcohol, in absence of CO 2, it converts into a carbamate and a secondary amine, while in the presence of CO2, the dialkyl carbonate, (RO)2CO, is formed together with urea [CyHN-CO-NHCy]. The reaction has been tested with various aliphatic alcohols such as methanol, ethanol, and allyl alcohol. It results in being a convenient route to the synthesis of diallyl carbonate, in particular. O-Methyl-N,N′-dicyclohexyl isourea also reacts with phenol in the presence of CO2 to directly afford for the very first time a mixed aliphatic-aromatic carbonate, (MeO)(PhO)CO. A DFT study has allowed us to estimate the energy of each intermediate and the relevant kinetic barriers in the described reactions, providing reasonable mechanistic details. Calculated data match very well the experimental results. The driving force of the reaction is the conversion of carbodiimide into the relevant urea, which is some 35 kcal/mol downhill with respect to the parent compound. The best operative conditions have been defined for achieving a quantitative yield of carbonate from carbodiimide. The role of temperature, pressure, and catalysts (Lewis acids and bases) has been established. As the urea can be reconverted into DCC, the reaction described in this article may further be developed for application to the synthesis of organic carbonates under selective and mild conditions.
- Aresta, Michele,Dibenedetto, Angela,Fracchiolla, Elisabetta,Giannoccaro, Potenzo,Pastore, Carlo,Papai, Imre,Schubert, Gabor
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p. 6177 - 6186
(2007/10/03)
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- Facile cleavage of Si-C bonds during the sol-gel hydrolysis of aminomethyltrialkoxysilanes - A new method for the methylation of primary amines
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The reaction of chloromethyltriethoxysilane with (1R,2R)-bis(methylamino) cyclohexane (1) afforded the corresponding bis-silylated compound 2. The sol-gel hydrolysis of 2 did not give the expected bridged silsesquioxane owing to quantitative Si-C-bond cleavage. Instead, silica and (1R,2R)-bis(dimethylamino) cyclohexane (3) were obtained. This reaction was exploited to propose a new route for the methylation of amines. Such methylation reaction of amines could be extended to other amines and provides a new method for the selective monomethylation of primary amines. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004.
- Adima, Augustin,Bied, Catherine,Moreau, Joel J. E.,Man, Michel Wong Chi
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p. 2582 - 2588
(2007/10/03)
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- Macrolide antibiotics and treatment and prophylaxis of pasteurellosis using the same
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20,23-disubstituted mycaminosyltylonolide derivatives and use of the same in the field of the prophylaxis and treatment of pasteurellosis are disclosed. The di-substituents are peperidino optionally substituted with one or two methyl groups. The derivatives have selective antibacterial activity against Pasteurella.
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- Convenient procedure for one-pot conversion of azides to N-monomethylamines
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One-pot conversion of azides to N-monomethylamines is described. Two optional protocols have been developed, which share the first stage, the reaction of an azide with (CH3)3P to generate the corresponding iminophosphorane. This Staudinger intermediate, thus generated, is either methylated with CH3I and hydrolyzed (method A), or treated with (HCHO)n and reduced with NaBH4 (method B), thereby giving the corresponding N-monomethylamine in high yield.
- Kato,Ohmori,Suzuki
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p. 1003 - 1005
(2007/10/03)
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- Scavenger assisted combinatorial process for preparing libraries of amides, carbamates and sulfonamides
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This invention relates to a novel solution phase process for the preparation of amide, carbamate, and sulfonamide combinatorial libraries. These libraries have utility for drug discovery and are used to form wellplate components of novel assay kits.
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- Facile preparation of N-methyl secondary amines by titanium(IV) isopropoxide-mediated reductive animation of carbonyl compounds
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A simple, mild and efficient procedure for obtaining N-methyl secondary amines from aldehydes and ketones is reported. Treatment of carbonyl compounds with methylamine hydrochloride, triethylamine and titanium(IV) isopropoxide, followed by in situ sodium borohydride reduction and straightforward aqueous work-up, affords clean products in good to excellent yields.
- Neidigh, Kurt A.,Avery, Mitchell A.,Williamson, John S.,Bhattacharyya, Sukanta
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p. 2527 - 2531
(2007/10/03)
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- Deoxygenation of N,N-disubstituted hydroxylamines by carbon disulfide
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Hindered N,N-dialkylhydroxylamines react rapidly with CS2 to give the corresponding 2°-amines.
- Schwartz, Martin A.,Gu, Jiping,Hu, Xiufeng
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p. 1687 - 1688
(2007/10/02)
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- ELECTROCHEMICAL REDUCTIVE AMINATION. I. AMINATION OF ALIPHATIC KETONES BY PRIMARY AMINES
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The reductive amination of aliphatic ketones in aqueous solutions of primary amines was realized by an electrochemical method.The best yields of the secondary amines were obtained at lead and cadmium cathodes in an aqueous electrolytic solution at pH 11-12.Elongation and branching in the carbon chain of the radicals both of the ketone and of the primary amine lead to a reduction in the yield of the secondary amine.The yield of the secondary amine is mainly determined by the rate of the chemical reaction leading to the formation of the azomethine compound, preceding the electrochemical reduction stage.
- Smirnov, Yu. D.,Tomilov, A. P.
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