- Intramolecular C?H Amination of N-Alkylsulfamides by tert-Butyl Hypoiodite or N-Iodosuccinimide
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1,3-Diamines are an important class of compounds that are broadly found in natural products and are also widely used as building blocks in organic synthesis. Although the intramolecular C?H amination of N-alkylsulfamide derivatives is a reliable method for the construction of 1,3-diamine structures, the majority of these methods involve the use of a transition-metal catalyst. We herein report on a new transition-metal-free method using tert-butyl hypoiodite (t-BuOI) or N-iodosuccinimide (NIS), enabling secondary non-benzylic and tertiary C?H amination reactions to proceed. The cyclic sulfamide products can be easily transformed into 1,3-diamines. Mechanistic investigations revealed that amination reactions using t-BuOI or NIS each proceed via different pathways.
- Kiyokawa, Kensuke,Jou, Keisuke,Minakata, Satoshi
-
supporting information
p. 13971 - 13976
(2021/08/30)
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- Rhodium-Catalyzed Anti-Markovnikov Hydroamination of Aliphatic and Aromatic Terminal Alkynes with Aliphatic Primary Amines
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Anti-Markovnikov hydroamination of both aliphatic and aromatic terminal alkynes with primary amines was achieved using an 8-quinolinolato rhodium catalyst to form aldimines and enamines in high yields. This catalytic system realized high functional group tolerance including hydroxy, bromo, cyano, and thioester groups.
- Kakiuchi, Fumitoshi,Kochi, Takuya,Morimoto, Yoshihiko
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p. 13143 - 13152
(2021/09/28)
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- Highly economical and direct amination of sp3carbon using low-cost nickel pincer catalyst
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Developing more efficient routes to achieve C-N bond coupling is of great importance to industries ranging from products in pharmaceuticals and fertilizers to biomedical technologies and next-generation electroactive materials. Over the past decade, improvements in catalyst design have moved synthesis away from expensive metals to newer inexpensive C-N cross-coupling approaches via direct amine alkylation. For the first time, we report the use of an amide-based nickel pincer catalyst (1) for direct alkylation of amines via activation of sp3 C-H bonds. The reaction was accomplished using a 0.2 mol% catalyst and no additional activating agents other than the base. Upon optimization, it was determined that the ideal reaction conditions involved solvent dimethyl sulfoxide at 110 °C for 3 h. The catalyst demonstrated excellent reactivity in the formation of various imines, intramolecularly cyclized amines, and substituted amines with a turnover number (TON) as high as 183. Depending on the base used for the reaction and the starting amines, the catalyst demonstrated high selectivity towards the product formation. The exploration into the mechanism and kinetics of the reaction pathway suggested the C-H activation as the rate-limiting step, with the reaction second-order overall, holding first-order behavior towards the catalyst and toluene substrate.
- Brandt, Andrew,Rangumagar, Ambar B.,Szwedo, Peter,Wayland, Hunter A.,Parnell, Charlette M.,Munshi, Pradip,Ghosh, Anindya
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p. 1862 - 1874
(2021/01/20)
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- Synthesis of an Fe-Pd bimetallic catalyst for: N -alkylation of amines with alcohols via a hydrogen auto-transfer methodology
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Hydrogen auto-transfer (HAT) or borrowing hydrogen (BH) methodology which combines dehydrogenation, intermediate reaction and hydrogenation, is recognized as an excellent strategy for one-pot synthesis from an economic and environmental point of view. Although much effort has been made on the development of catalysts for HAT reactions, harsh conditions, external base or large amounts of noble metals are still required in most reported catalysis systems, and thus the exploration of a highly efficient and recyclable heterogeneous catalyst remains meaningful. In this work, a novel bimetallic catalyst, Fe10Pd1/NC500 derived from bimetallic MOF NH2-MIL-101(Fe10Pd1), has been prepared, and the catalyst exhibits superior catalytic performance for the N-alkylation of amines with alcohols via a hydrogen auto-transfer methodology. High yields of the desired products were achieved at 120 °C with an alcohol/amine molar ratio of 2?:?1 and required no external additive or solvent. A distinct enhancement in catalytic performance is observed when compared with monometallic catalysts, which can be ascribed to the "synergistic effects"inside the bimetallic alloys. The N-doped carbon support has been revealed to provide the necessary basicity which avoids the requirement of an external base. Moreover, a wide substrate range and remarkable reusability have been shown by Fe10Pd1/NC500, and this work highlights new possibilities for bimetallic catalysts applied in sustainable chemistry.
- Wu, Peng-Yu,Lu, Guo-Ping,Cai, Chun
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p. 396 - 404
(2021/01/28)
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- Half-Sandwich Ru(II) Complexes with N,O-Chelate Ligands: Diverse Catalytic Activity for Amine Synthesis in Water
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Several types of β-ketoamino based N,O-coordinate half-sandwich ruthenium complexes have been synthesized in moderate to good yields. The stable ruthenium complexes displayed good and diverse catalytic efficiency in reductive amination between aldehydes and amines in aqueous solution. The method gave a facile route for one-pot synthesis of diverse complicated amines with a low catalyst loading by using cheap and less-toxic HCOOH or clean H2 as hydrogen source. Catalyst Ru1 showed the highest catalytic activity of 190 h-1 TOF value in the reductive amination reaction of benzaldehyde with aniline. The corresponding amine products were furnished in excellent yields under the standard catalysis system. The efficient and diverse catalytic activity, broad substance scope, mild conditions, and environmentally benign solvent made this system potentially applicable in industrial production. Ruthenium complexes were characterized using NMR, elemental analysis, and IR techniques to confirm their structure.
- Yun, Xue-Jing,Ling, Chun,Deng, Wei,Liu, Zhen-Jiang,Yao, Zi-Jian
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p. 3830 - 3838
(2020/11/13)
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- Cross-linked cyclodextrins bimetallic nanocatalysts: Applications in microwave-assisted reductive aminations
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The optimization of sustainable protocols for reductive amination has been a lingering challenge in green synthesis. In this context, a comparative study of different metal-loaded cross-linked cyclodextrins (CDs) were examined for the microwave (MW)-assisted reductive amination of aldehydes and ketones using either H2 or formic acid as a hydrogen source. The Pd/Cu heterogeneous nanocatalyst based on Pd (II) and Cu (I) salts embedded in a β-CD network was the most efficient in terms of yield and selectivity attained. In addition, the polymeric cross-linking avoided metal leaching, thus enhancing the process sustainability; good yields were realized using benzylamine under H2. These interesting findings were then applied to the MW-assisted one-pot synthesis of secondary amines via a tandem reductive amination of benzaldehyde with nitroaromatics under H2 pressure. The formation of a CuxPdy alloy under reaction conditions was discerned, and a synergic effect due to the cooperation between Cu and Pd has been hypothesized. During the reaction, the system worked as a bifunctional nanocatalyst wherein the Pd sites facilitate the reduction of nitro compounds, while the Cu species promote the subsequent imine hydrogenation affording structurally diverse secondary amines with high yields.
- Acciardo, Elisa,Cravotto, Giancarlo,Gaudino, Emanuela Calcio,Manzoli, Maela,Tabasso, Silvia,Varma, Rajender S.
-
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- Cine-Silylative Ring-Opening of α-Methyl Azacycles Enabled by the Silylium-Induced C-N Bond Cleavage
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Described herein is the development of a borane-catalyzed cine-silylative ring-opening of α-methyl azacycles. This transformation involves four-step cascade processes: (i) exo-dehydrogenation of alicyclic amine, (ii) hydrosilylation of the resultant enamine, (iii) silylium-induced cis-β-amino elimination to open the ring skeleton, and (iv) hydrosilylation of the terminal olefin. The present borane catalysis also works efficiently for the C-N bond cleavage of acyclic tertiary amines. On the basis of experimental and computational studies, the silicon atom was elucidated to play a pivotal role in the β-amino elimination step.
- Zhang, Jianbo,Chang, Sukbok
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p. 12585 - 12590
(2020/08/21)
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- High-Throughput Screening of Reductive Amination Reactions Using Desorption Electrospray Ionization Mass Spectrometry
-
This study describes the latest generation of a high-throughput screening system that is capable of screening thousands of organic reactions in a single day. This system combines a liquid handling robot with desorption electrospray ionization (DESI) mass spectrometry (MS) for a rapid reaction mixture preparation, accelerated synthesis, and automated MS analysis. A total of 3840 unique reductive amination reactions were screened to demonstrate the throughputs that are capable with the system. Products, byproducts, and intermediates were all monitored in full-scan mass spectra, generating a complete view of the reaction progress. Tandem mass spectrometry experiments were conducted to verify the identity of the products formed. The amine and electrophile reactivity trends represented in the data match what is expected from theory, indicating that the system accurately models the reaction performance. The DESI results correlated well with those generated using more traditional mass spectrometry techniques like liquid chromatography-mass spectrometry, validating the data generated by the system.
- Cooks, R. Graham,Ferreira, Christina R.,Li, Yangjie,Logsdon, David L.,Paschoal Sobreira, Tiago Jose,Thompson, David H.
-
supporting information
p. 1647 - 1657
(2020/10/26)
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- Biocatalytic N-Alkylation of Amines Using Either Primary Alcohols or Carboxylic Acids via Reductive Aminase Cascades
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The alkylation of amines with either alcohols or carboxylic acids represents a mild and safe alternative to the use of genotoxic alkyl halides and sulfonate esters. Here we report two complementary one-pot systems in which the reductive aminase (RedAm) from Aspergillus oryzae is combined with either (i) a 1° alcohol/alcohol oxidase (AO) or (ii) carboxylic acid/carboxylic acid reductase (CAR) to affect N-alkylation reactions. The application of both approaches has been exemplified with respect to substrate scope and also preparative scale synthesis. These new biocatalytic methods address issues facing alternative traditional synthetic protocols such as harsh conditions, overalkylation and complicated workup procedures.
- Ramsden, Jeremy I.,Heath, Rachel S.,Derrington, Sasha R.,Montgomery, Sarah L.,Mangas-Sanchez, Juan,Mulholland, Keith R.,Turner, Nicholas J.
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p. 1201 - 1206
(2019/01/21)
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- New alkenyl derivative from Piper malacophyllum and analogues: Antiparasitic activity against Trypanosoma cruzi and Leishmania infantum
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Alkylphenols isolated from Piper malacophyllum (Piperaceae), gibbilimbols A and B, showed interesting activity against the parasites Trypanosoma cruzi and Leishmania infantum. In continuation to our previous work, a new natural product from the essential
- Varela, Marina T.,Lima, Marta L.,Galuppo, Mariana K.,Tempone, Andre G.,de Oliveira, Alberto,Lago, Jo?o Henrique G.,Fernandes, Jo?o Paulo S.
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p. 1007 - 1011
(2017/09/30)
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- METHODS FOR THE SYNTHESIS OF CERAGENINS
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Disclosed herein are methods of making ceragnenin compounds for treating, preventing, or diagnosing diseases, disorders, or conditions associated with bacterial or viral infections, cancer, inflammation, and osteogenesis. Ceragenin compounds display broad-spectrum antibacterial activity utilizing a mode of action similar to antimicrobial peptides, but without the high synthesis costs and susceptibility to proteolytic degradation. Ceragenin compounds reproduce the amphiphilic morphology found in many antimicrobial peptides and display potent and diverse biological activities, including anti-bacterial, anti-cancer, anti-inflammatory, bone growth promotion, and wound healing promotion.
- -
-
Paragraph 0153-0154
(2016/11/14)
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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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- Selective Activation of Alcohols in the Presence of Reactive Amines over Intermetallic PdZn: Efficient Catalysis for Alcohol-Based N-Alkylation of Various Amines
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Pd-based intermetallic compounds supported on Al2O3 (PdxMy/Al2O3, where M = Bi, Cu, Fe, Ga, In, Pb, Sn, or Zn) were prepared and tested as catalysts for the selective activation of alcohols in the presence of reactive amines, which is highly challenging and is the key strategy for alcohol-based N-alkylation of amines. Although the Pd/Al2O3 catalyst exhibited a high catalytic activity, undesired side reactions such as amine dimerization (via amine activation) and C-O bond scission occurred, resulting in a poor yield of the N-alkylation product. In contrast, the PdZn/Al2O3 catalyst acted as an efficient catalyst for this reaction, displaying high catalytic activities, selectivities, and atom efficiencies and a wide substrate scope. Detailed kinetic and computational studies revealed that the relative affinity of Pd for alcohol and amine drastically changes by the formation of a PdZn intermetallic phase. On monometallic Pd, the adsorption and activation of amines are preferred over those of alcohols in terms of thermodynamic and kinetic aspects, respectively. However, this trend is inverted on PdZn, allowing preferential adsorption and activation of alcohols and, hence, selective N-alkylation.
- Furukawa, Shinya,Suzuki, Ryohei,Komatsu, Takayuki
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p. 5946 - 5953
(2016/09/09)
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- Contra-thermodynamic Hydrogen Atom Abstraction in the Selective C-H Functionalization of Trialkylamine N-CH3 Groups
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We report a simple one-pot protocol that affords functionalization of N-CH3 groups in N-methyl-N,N-dialkylamines with high selectivity over N-CH2R or N-CHR2 groups. The radical cation DABCO+?, prepared in situ by oxidation of DABCO with a triarylaminium salt, effects highly selective and contra-thermodynamic C-H abstraction from N-CH3 groups. The intermediates that result react in situ with organometallic nucleophiles in a single pot, affording novel and highly selective homologation of N-CH3 groups. Chemoselectivity, scalability, and recyclability of reagents are demonstrated, and a mechanistic proposal is corroborated by computational and experimental results. The utility of the transformation is demonstrated in the late-stage site-selective functionalization of natural products and pharmaceuticals, allowing rapid derivatization for investigation of structure-activity relationships.
- Barham, Joshua P.,John, Matthew P.,Murphy, John A.
-
supporting information
p. 15482 - 15487
(2016/12/09)
-
- Selective and recyclable rhodium nanocatalysts for the reductive N-alkylation of nitrobenzenes and amines with aldehydes
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Rhodium nanocatalysts were prepared and applied for the reductive N-alkylation of nitrobenzenes and amines to the corresponding secondary amines with aldehydes and ketones. Functional nitrobenzenes, such as nitrobenzenes with F, Cl, Br, CH3O and CH3 were transformed to the corresponding secondary amines in good to excellent yields. Moreover, the Rh@CN catalyzed N-alkylation of a series of primary amines with aldehydes and ketones also gave the corresponding secondary amines in high yields. The Rh@CN is heterogeneous, and can be reusable several times (at least 4 times) for the reductive N-alkylation of nitroarenes.
- Huang, Lei,Wang, Zhi,Geng, Longfei,Chen, Rizhi,Xing, Weihong,Wang, Yong,Huang, Jun
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p. 56936 - 56941
(2015/07/15)
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- Tunable dehydrogenative amidation versus amination using a single ruthenium-NHC catalyst
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Mixed N-heterocyclic carbene (NHC)/phosphine complexes of the type [RuCl(p-cymene)(bimy)(PPh3)]- PF6 (bimy = benzimidazolin-2-ylidene) have been synthesized and fully characterized. Complex 1 bearing the 1,3-dibenzylbenzimidazolin-2-ylidene ligand is able to selectively catalyze both dehydrogenative amidation, mono-, and diamination (N-alkylation) through coupling of simple alcohols with amines effectively yielding a range of amides and secondary and tertiary amines. Selectivity is achieved by controlling the fate of the common hemiaminal intermediate, which in turn can be simply influenced by the choice of base and solvent.
- Xie, Xiaoke,Huynh, Han Vinh
-
p. 4143 - 4151
(2015/11/11)
-
- CATALYST COMPOUNDS
-
The present invention relates to an iridium-based catalyst compound for hydrogenating reducible moieties, especially imines and iminiums, the catalyst compounds being defined by the formulas: where ring B is either itself polycyclic, or ring B together with R is polycyclic. The catalysts of the invention are particularly effective in reductive amination procedures 10 which involve the in situ generation of the imine or iminium under reductive hydrogenative conditions.
- -
-
Paragraph 0314; 0327
(2015/03/28)
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- Method of producing higher amine (by machine translation)
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PROBLEM TO BE SOLVED: To provide a method of producing a secondary or tertiary higher amine. SOLUTION: The method of producing a higher amine comprises allowing a primary or secondary amine to react with an alcohol in the presence of at least one species of hydrogen halide selected from hydrogen chloride, hydrogen bromide and hydrogen iodide, or in the presence of a compound capable of producing a hydrogen halide (such as 1,3,5-triazo-2,4,6-triphosphorine-2,2,4,4,6,6-chloride). If the raw material amine is a primary amine, a secondary higher amine and a tertiary higher amine can be produced. If the raw material amine is a secondary amine, a tertiary higher amine can be produced. COPYRIGHT: (C)2012,JPO&INPIT
- -
-
Paragraph 0048; 0073; 0077
(2016/10/08)
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- Graphene-supported NiPd alloy nanoparticles: A novel and highly efficient heterogeneous catalyst system for the reductive amination of aldehydes
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A novel and highly efficient heterogeneous catalytic reductive amination of aldehydes is described. The recently developed graphene supported NiPd alloy nanoparticle (G-NiPd) catalyst using ammonia borane (AB) as a green, stable and safe hydrogen donor was used in a water/methanol mixture (v/v = 2/3) under ambient conditions. The catalytic system was successfully applied in the reductive amination of various substituted aldehydes with amines and the corresponding products were obtained in (up to) 99% yield in 6 h. The G-NiPd catalyst could be recycled up to five times without any significant loss in the product yield.
- Ni?anci, Bilal,Ganjehyan, Khadijeh,Metin, ?nder,Da?tan, Arif,T?r?k, Béla
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p. 191 - 197
(2015/09/22)
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- An efficient heterogenized palladium catalyst for N-alkylation of amines and α-alkylation of ketones using alcohols
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A silica supported palladium-NiXantphos complex is reported as an efficient and a high turnover heterogeneous catalyst for the N-alkylation of amines and the α-alkylation of ketones using readily available alcohols under neat conditions at 120-140 °C following hydrogen borrowing strategy. The catalyst is easily separable and offers negligible amount of palladium leaching (0.01 ppm). A high turnover number of about 46000 for the N-alkylation of amines and 4400 for the α-alkylation of ketones were achieved in the respective single batch reactions. The catalyst is recyclable up to four times without appreciable change in catalytic performance.
- Dang, Tuan Thanh,Shan, Siah Pei,Ramalingam, Balamurugan,Seayad, Abdul Majeed
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p. 42399 - 42406
(2015/05/20)
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- Ag nanoparticles on mixed Al2O3-Ga2O 3 supports as catalysts for the N-alkylation of amines with alcohols
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The combination of AgNO3 with NaH results in Ag nanoparticles that can selectively perform alcohol aminations under mild reaction conditions (110 C). NaH not only serves as a reducing agent for the Ag salt, but also activates the alcohol for dehydrogenation to the corresponding ketone/aldehyde. The stability of the particles can be improved by immobilizing them onto mixed Al2O3-Ga2O3 supports; the combination of Ga and Al provides materials with stronger Lewis acidic sites compared to pure alumina or gallium oxide supports. This leads to catalysts with enhanced activities, without the necessity of adding external Lewis acids. Detailed TEM characterization also reveals a close interaction between the Ag NPs and the gallium oxide phase. The obtained catalysts are recyclable and show activity for the alcohol amination using a variety of aliphatic and aromatic amines under mild conditions.
- Geukens, Inge,Vermoortele, Frederik,Meledina, Maria,Turner, Stuart,Van Tendeloo, Gustaaf,De Vos, Dirk E.
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p. 373 - 379
(2013/11/19)
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- General and selective reductive amination of carbonyl compounds using a core-shell structured Co3O4/NGr@C catalyst
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The application of heterogenized non-noble metal-based catalysts in selective catalytic hydrogenation processes is still challenging. In this respect, the preparation of a well-defined cobalt-based catalyst was investigated by immobilization of the corresponding cobalt(ii)-phenanthroline-chelate on Vulcan XC72R carbon powder. The formed core-shell structured cobalt/cobalt oxide nanocomposites are encapsulated by nitrogen-enriched graphene layers. This promising cheap heterogeneous catalyst allows for an efficient domino reductive amination of carbonyl compounds with nitroarenes. This journal is
- Stemmler, Tobias,Westerhaus, Felix A.,Surkus, Annette-Enrica,Pohl, Marga-Martina,Junge, Kathrin,Beller, Matthias
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p. 4535 - 4540
(2014/12/10)
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- Iron-catalyzed synthesis of secondary amines: On the way to green reductive aminations
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Amines represent important intermediates in chemical and biological processes. Herein, we describe the use of a nanostructured iron-based catalyst for the tandem reductive amination between nitroarenes and aldehydes using hydrogen as reductant. The nanostructured iron-catalyst is prepared by immobilization of an iron-phenanthroline complex onto a commercially available carbon support. In the reaction sequence a primary amine is formed in situ from the corresponding nitro compound. Reversible condensation with aldehydes forms the respective imines, which are finally reduced to the desired secondary amine. This synthesis of secondary amines is atom-economical and environmentally attractive using cheap and readily available organic compounds as starting materials.
- Stemmler, Tobias,Surkus, Annette-Enrika,Pohl, Marga-Martina,Junge, Kathrin,Beller, Matthias
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p. 3012 - 3016
(2015/09/28)
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- Selective N-alkylation of primary amines with R-NH2·HBr and alkyl bromides using a competitive deprotonation/protonation strategy
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Monoalkylation of primary amines using amine hydrobromides and alkyl bromides has been carried out. Under controlled reaction conditions the reactant primary amine was selectively deprotonated and made available for reaction, while the newly generated secondary amine remained protonated, and did not participate in alkylation further. Reaction was carried out under mild reaction conditions and was applicable to a wide range of primary amines and alkyl bromides.
- Bhattacharyya, Shubhankar,Pathak, Uma,Mathur, Sweta,Vishnoi, Subodh,Jain, Rajeev
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p. 18229 - 18233
(2014/05/20)
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- Reusable supported ruthenium catalysts for the alkylation of amines by using primary alcohols
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Efficient and recyclable ruthenium catalysts were synthesized from readily available polystyrene-or silica-supported phosphine ligands. Catalysts bound to the polymer support through an ether linkage showed good to excellent activity towards the N-alkylation of primary and secondary amines to afford the alkylated products in 62-99 % yield at 120-140°C. The supported phosphine ligand/ruthenium ratio was found to be crucial for higher catalytic activity and lower ruthenium leaching. The continuous flow N-alkylation of amines was demonstrated by using the supported catalyst in a column reactor. By adopting the hydrogen-borrowing strategy, the synthesis of the anti-Parkinson agent Piribedil was established in 98 % yield at 140°C. Support group steals the show: An efficient Ru-based heterogeneous catalyst from readily available supported phosphine ligands is developed. The nature of the linkage and the extent of ruthenium incorporation are crucial in determining the catalytic activity. The catalyst can be recycled and used under continuous flow in a packed-bed reactor. The alkylation of cyclic amines is achieved in excellent yield at moderate temperatures in the absence of any external base.
- Peishan, Siah,Dang, Tuan Thanh,Seayad, Abdul Majeed,Ramalingam, Balamurugan
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p. 808 - 814
(2014/03/21)
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- Fast reductive amination by transfer hydrogenation "on water"
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Reductive amination of various ketones and aldehydes by transfer hydrogenation under aqueous conditions has been developed, by using cyclometallated iridium complexes as catalysts and formate as hydrogen source. The pH value of the solution is shown to be critical for a high catalytic chemoselectivity and activity, with the best pH value being 4.8. In comparison with that in organic solvents, the reductive amination in an aqueous phase is faster, and the molar ratio of the substrate to the catalyst (S/C) can be set as high as 1×105, the highest S/C value ever reported in reductive amination reactions. The catalyst is easy to access and the reaction is operationally simple, allowing a wide range of ketones and aldehydes to react with various amines in high yields. The protocol provides a practical and environmental friendly new method for the synthesis of amine compounds. Greener amine synthesis: A versatile reductive amination protocol has been developed. By using an iridium catalyst in water, a broad range of ketones and aldehydes react with amines to afford various new amines in good yields (see scheme), with molar ratios of the substrate to the catalyst (S/C) as high as 1×10 5. The pH of the reaction solution plays a key role, regulating both the catalytic activity and the selectivity. Copyright
- Lei, Qian,Wei, Yawen,Talwar, Dinesh,Wang, Chao,Xue, Dong,Xiao, Jianliang
-
supporting information
p. 4021 - 4029
(2013/04/10)
-
- Solvent- and catalyst-free direct reductive amination of aldehydes and ketones with Hantzsch ester: Synthesis of secondary and tertiary amines
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A facile and rapid method for the parallel synthesis of a series of secondary and tertiary amines by the direct reductive amination of aldehydes and ketones with Hantzsch ester under solvent- and catalyst-free has been developed. The scope and limitation of this method are described.
- Nguyen, Quynh Pham Bao,Kim, Taek Hyeon
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p. 4938 - 4943
(2013/07/25)
-
- CATALYST COMPOUNDS
-
The present invention relates to an iridium-based catalyst compound for hydrogenating reducible moieties, especially imines and iminiums, the catalyst compounds being defined by the formulas: where ring B is either itself polycyclic, or ring B together with R is polycyclic. The catalysts of the invention are particularly effective in reductive amination procedures 10 which involve the in situ generation of the imine or iminium under reductive hydrogenative conditions.
- -
-
Paragraph 00163; 00176
(2013/11/05)
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- N-alkylation of amines by homogeneous ruthenium complexes in the presence of free diphosphines
-
Chemoselective N-alkylation of amines by ruthenium complexes in the presence of free diphosphine ligands under mild conditions is described. Octyl amine and aniline were chosen as aliphatic and aromatic amines to investigate the effect of different phosphines, reaction times, and temperature on conversion, as well as selectivity towards related secondary and tertiary amines. After optimization of the reaction conditions, this catalytic system was used for N-alkylation of other amines and has shown moderate to very good yields. The reaction products were monitored by GC-MS. The crystal structure of [Ru(NO3)2CO(PPh3)2] with a monodentate and a bidentate nitrate was determined by X-ray crystallographic analysis.
- Tamaddoni Jahromi, Bahareh,Kharat, Ali Nemati
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p. 3498 - 3508
(2014/01/06)
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- Selective alkylation of amines with alcohols by Cp*- iridium(III) half-sandwich complexes
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[Cp*Ir(Pro)Cl] (Pro = prolinato) was identified among a series of Cp*-iridium half-sandwich complexes as a highly reactive and selective catalyst for the alkylation of amines with alcohols. It is active under mild conditions in either toluene or water without the need for base or other additives, tolerates a wide range of alcohols and amines, and gives secondary amines in good to excellent isolated yields.
- Wetzel, Alexander,Woeckel, Simone,Schelwies, Mathias,Brinks, Marion K.,Rominger, Frank,Hofmann, Peter,Limbach, Michael
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supporting information
p. 266 - 269
(2013/03/14)
-
- Heterogeneously catalyzed self-condensation of primary amines to secondary amines by supported copper catalysts
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Self-condensation of primary amines to symmetrically substituted secondary amines could efficiently be promoted by an inexpensive supported copper catalyst, Cu/Al2O3, easily prepared by the reduction of the hydroxide precursor, Cu(OH)x/Al2O3. Various kinds of structurally diverse primary amines including benzylamine, picolylamine, and aliphatic amine derivatives could selectively be converted into the corresponding secondary amines in moderate to excellent yields without any cocatalysts such as bases and stabilizing ligands in 1 atm of Ar or H 2. The reactions in H2 showed higher selectivities to desired secondary amines than those in Ar. The roles of H2 are the promotion of hydrogenation of N-alkylimines and the stabilization of active Cu(0) species. In addition, in the presence of Cu/Al2O3, unsymmetrically substituted secondary amines could efficiently be synthesized by N-alkylation of primary amines with alcohols and reductive amination of aldehydes. The observed catalysis was truly heterogeneous, and the retrieved Cu/Al2O3 catalyst could be reused for self-condensation without a significant loss of its catalytic performance. The reaction mechanism involving dehydrogenation of primary amines and condensation to N-alkylimines followed by hydrogenation, the so-called "borrowing hydrogen pathway", has been proposed. The Royal Society of Chemistry 2013.
- Kim, Insu,Itagaki, Shintaro,Jin, Xiongjie,Yamaguchi, Kazuya,Mizuno, Noritaka
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p. 2397 - 2403
(2013/09/02)
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- Heterogeneous Ni catalysts for N-alkylation of amines with alcohols
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Nickel nanoparticles loaded onto various supports (Ni/MOx) have been prepared and studied for the N-alkylation of amines with alcohols. Among the catalysts, Ni/θ-Al2O3 prepared by in situ H 2-reduction of NiO/θ-Al2O3 shows the highest activity, and it acts as reusable heterogeneous catalyst for the alkylation of anilines and aliphatic amines with various alcohols (benzyl and aliphatic alcohols) under additive free conditions. Primary amines are converted into secondary amines and secondary amines into tertiary amines. For the reaction of aniline with an aliphatic alcohol the catalyst shows higher turnover number (TON) than precious metal-based state-of-the-art catalysts. Mechanistic studies suggest that the reaction proceeds through a hydrogen-borrowing mechanism. The activity of Ni catalysts depends on the nature of support materials; acid-base bifunctional supports give higher activity than basic or acidic supports, indicating that acid-base sites on supports are necessary. The presence of basic (pyridine) or acidic (acetic acid) additive in the solution decreased the activity of Ni/θ-Al2O3, which suggests the cooperation of the acid-base site of θ-Al2O3. For a series of Ni/θ-Al2O3 catalysts with different particle size, the turnover frequency (TOF) per surface Ni increases with decreasing Ni mean particle size, indicating that low-coordinated Ni species and/or metal-support interface are active sites. From these results, we propose that the active site for this reaction is metal-support interface, where low-coordinated Ni0 atoms are adjacent to the acid-base sites of alumina.
- Shimizu, Ken-Ichi,Imaiida, Naomichi,Kon, Kenichi,Hakim Siddiki,Satsuma, Atsushi
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p. 998 - 1005
(2013/06/27)
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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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- 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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- Impregnated palladium on magnetite as catalyst for multicomponent reductive amination reactions and other related reducing processes
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The impregnated palladium on magnetite catalyst is a versatile system for different reduction processes using inexpensive polymehtylhydrosiloxane, including multicomponent reductive amination reactions, and aldehyde, imine, sulfinimide and sulfoxide reductions. This catalyst avoids the use of any type of expensive and quite expensive organic ligand, showing excellent yields, under mild reaction conditions. The catalyst is easily removed from the reaction medium, just by using a magnet. The catalytic system is very selective permitting the discrimination between ketones and aldehydes in the reductive amination process.
- Cano, Rafael,Yus, Miguel,Ramón, Diego J.
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experimental part
p. 8079 - 8085
(2011/11/04)
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- Synthesis and antibacterial activity of aromatic and heteroaromatic amino alcohols
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Two series of aromatic and heteroaromatic amino alcohols were synthesized from alcohols and aldehydes and evaluated for their antibacterial activities. All the octylated compounds displayed a better activity against the four bacteria tested when evaluated by the agar diffusion method and were selected for the evaluation of minimal inhibitory concentration. The best results were obtained for p-octyloxybenzyl derivatives against Staphylococcus epidermidis (minimal inhibitory concentrations = 32μm).
- de Almeida, Camila G.,Reis, Samira G.,de Almeida, Angelina M.,Diniz, Claudio G.,da Silva, Vania L.,Le Hyaric, Mireille
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p. 876 - 880
(2012/06/18)
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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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- Mild nonepimerizing N -alkylation of amines by alcohols without transition metals
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A one-pot two-step sequence involving an oxidation/imine-iminium formation/reduction allowed the N-alkylation of amines by alcohols without any epimerization when optically active alcohols and amines are involved in the process.
- Guerin, Claire,Bellosta, Veronique,Guillamot, Gerard,Cossy, Janine
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supporting information; experimental part
p. 3534 - 3537
(2011/08/10)
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- Selective synthesis of secondary amines via N-alkylation of primary amines and ammonia with alcohols by supported copper hydroxide catalysts
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The N-alkylation of primary amines and ammonia (in situ generated from urea or aqueous ammonia) with alcohols to secondary amines was efficiently promoted by supported copper hydroxide catalysts, Cu(OH)xAl2O 3 and Cu(OH)x/TiO2. The observed catalysis was truly heterogeneous, and the catalysts could be reused without an appreciable loss of catalytic performance.
- He, Jinling,Yamaguchi, Kazuya,Mizuno, Noritaka
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supporting information; scheme or table
p. 1182 - 1183
(2011/02/28)
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- Titanium hydroamination catalysts bearing a 2-aminopyrrolinato spectator ligand: Monitoring the individual reaction steps
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A series of new titanium half sandwich complexes, containing a 2-aminopyrrolinato ligand {NXylN}- as the ancillary ligand, have been prepared and are shown to be pre-catalysts for the hydroamination of alkynes. The coordination of {NXylN}- to titanium was achieved by reaction of [Cp*TiMe3] with the protioligand NXylNH giving [Cp*Ti(NXylN)(Me) 2] (1). Upon reaction of complex 1 with an excess of tert-butylamine, the imido complex [Cp*Ti(NXylN)(NtBu)(NH 2tBu)] (2) was formed. The latter provided the preparative entry to the synthesis of a range of N-aryl substituted imido complexes. Imido ligand exchange with 2,6-dimethylaniline, 2,4,6-trimethylaniline as well as 2,6-diisopropylaniline gave the corresponding arylimido complexes 3-5 in clean reactions. Reaction of the titanium imido complex [Cp*Ti(N XylN)(NtBu)(NH2tBu)] 2 with terminal arylacetylenes, such as phenylacetylene and tolylacetylene, led to C-H activation and the formation of alkynyl/amido complexes, whereas the arylimido complexes 3 and 5 cleanly underwent {2 + 2} cycloaddition, giving the azatitanacyclobutene derivatives. A single-crystal X-ray structure analysis of the azatitanacyclobutene [Cp*Ti(NXylN){κ2N(2, 6-C6H3Me2)CTolCH}] (11) provided the first crystallographically characterized Markovnikov cycloaddition product of an imidotitanium complex with a terminal alkyne. The mechanistic aspects of the hydromanination of alkynes with the new Ti half sandwich complexes were studied and established a reversible {2 + 2} cycloaddition step and the cleavage of the metallacyclic intermediate as the rate determining step in the catalytic cycle. The titanium half sandwich imido complexes were found to be active catalysts for the inter- and intramolecular hydroamination of a broad range of alkynes and ω-aminoalkynes.
- Weitershaus, Katharina,Ward, Benjamin D.,Kubiak, Raphael,Mueller, Carsten,Wadepohl, Hubert,Doye, Sven,Gade, Lutz H.
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experimental part
p. 4586 - 4602
(2009/12/03)
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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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- Hydrogen-transfer reductive amination of aldehydes catalysed by nickel nanoparticles
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Nickel nanoparticles have been found to catalyse the reductive amination of aldehydes by transfer hydrogenation with isopropanol at 76°C. Georg Thieme Verlag Stuttgart.
- Alonso, Francisco,Riente, Paola,Yus, Miguel
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experimental part
p. 1289 - 1292
(2009/04/06)
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- Neutral Ti complexes as catalysts for the hydroamination of alkynes and alkenes: Do the labile ligands change the catalytic activity?
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A detailed comparison between three four-coordinate Ti complexes featuring the general bidentate ligand [η5-(C5H 4)-SiMe2-NtBu]2- and two ligands X (NMe 2, Me, Cl) as catalyst precursors (I-III) for the intermolecular hydroamination of alkynes and the intramolecular hydroamination of alkenes is presented. The results strongly suggest that the catalytically active species are only identical for reactions performed with the bis(dimethylamido) complex I or the dimethyl complex II. Under the reaction conditions, the labile ligands X are proteolytically removed by the reacting amine to form catalytically active imido or amido complexes, together with dimethylamine or methane. Although both catalyst precursors can be used successfully for many substrate combinations, the preparative and kinetic studies clearly indicate that dimethylamine, which is formed from the bis(dimethylamido) catalyst precursor I and the reacting amine, is able to convert the catalytically active imido or amido complexes back into the catalyst precursor and therefore inhibits the reactions. As a consequence, the bis(dimethylamido) catalyst precursor I shows a poorer catalytic performance than the corresponding dimethyl complex II. Additionally, it is shown that the dichloro complex III is only a suitable catalyst precursor for selected hydroamination reactions. Corresponding reactions that are more difficult to achieve - such as reactions of diarylalkynes or amino alkenes - do not work efficiently with this complex. A possible explanation for this observation is the finding that the dichloro catalyst precursor III is obviously converted into a different catalytically active species. This can happen if the [η5-(C5H4)-SiMe2-NtBu]-ligand system of the catalyst precursor is being destroyed and removed from the Ti center under the reaction conditions. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.
- Graebe, Kerstin,Pohlki, Frauke,Doye, Sven
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experimental part
p. 4815 - 4823
(2009/05/07)
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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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- Reductive amination of carbonyl compounds using NaBH4 in a Br?nsted acidic ionic liquid
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Reductive amination of carbonyl compounds using sodium borohydride is conducted in the Br?nsted acidic ionic liquid, 1-methyl imidazolium tetrafluoroborate ([HMIm][BF4]). The ionic liquid plays the dual role of solvent as well as catalyst for efficient conversion of aldehydes and ketones to amines in excellent yields without the formation of side products.
- Reddy, P. Srinivasa,Kanjilal, Sanjit,Sunitha,Prasad, Rachapudi B.N.
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p. 8807 - 8810
(2008/03/18)
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- Anti-Markovnikov addition of both primary and secondary amines to terminal alkynes catalyzed by the TpRh(C2H4)2/PPH 3 system
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Terminal alkynes react with secondary amines in the presence of TpRh(C2H4)2/PPh3 (Tp = trispyrazolylborate) to give anti-Markovnikov E-enamines. Both Tp and PPh3 ligands are essential for the reaction. The reaction tolerates functional groups, such as ester, nitrile, and siloxy groups, on the terminal alkynes. Primary amines also add to terminal alkynes in anti-Markovnikov fashion, yielding the corresponding imines. The formation of a vinylidene-rhodium complex followed by the intermolecular nucleophilic attack by an amine nitrogen at the α-carbon atom of the vinylidene-metal intermediate may be involved in a key step in the catalytic reaction. Copyright
- Fukumoto, Yoshiya,Asai, Harumi,Shimizu, Masaki,Chatani, Naoto
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p. 13792 - 13793
(2008/04/04)
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- Convenient synthesis of 6,6-bicyclic malonamides: A new class of conformationally preorganized ligands for f-block ion binding
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A general synthetic approach was developed for the preparation of a series of 6,6-bicyclic malonamides, a class of ligands that provide a preorganized binding site for f-block ions (particularly trivalent lanthanides). The approach described is convenient to introduce a variety of functional groups at the amide nitrogens to tune the properties of the ligand without altering the preorganized binding. Each of the ten derivatives (that represent a range of functionality, including R = alkyl, hydroxy, phenyl, ester, perfluorocarbon) reported here derives from a single, readily prepared dialdehyde intermediate. This intermediate is converted to the final products via reductive amination with an appropriately functionalized benzylamine, followed by hydrogenolysis and lactam formation. Because derivatization occurs late in the synthesis, the approach is general, requiring only modification of the purification procedures for each new derivative. To aid in the purification of the bicyclic malonamides, we report a novel complexation-based purification method that takes advantage of the high affinity of the ligand for f-block metals.
- Parks, Bevin W.,Gilbertson, Robert D.,Domaille, Dylan W.,Hutchison, James E.
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p. 9622 - 9627
(2007/10/03)
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- Direct and indirect reductive amination of aldehydes and ketones with solid acid-activated sodium borohydride under solvent-free conditions
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A simple and convenient procedure for reductive amination of aldehydes and ketones using sodium borohydride activated by boric acid, p-toluenesulfonic acid monohydrate or benzoic acid as reducing agent under solvent-free conditions is described.
- Byung, Tae Cho,Sang, Kyu Kang
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p. 5725 - 5734
(2007/10/03)
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- One-pot reductive amination of aldehydes and ketones with α-picoline-borane in methanol, in water, and in neat conditions
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A one-pot reductive amination of aldehydes and ketones with amines using α-picoline-borane as a reducing agent is described. The reaction has been carried out in MeOH, in H2O, and in neat conditions in the presence of small amounts of AcOH. This is a highly efficient and mild procedure that is applicable for a wide variety of substrates. In particular, this is the first successful demonstration that this type of reaction can be carried out in water and in neat conditions.
- Sato, Shinya,Sakamoto, Takeshi,Miyazawa, Etsuko,Kikugawa, Yasuo
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p. 7899 - 7906
(2007/10/03)
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- Synthesis of secondary amines by reduction of α-amidoalkylphenyl sulfones with sodium acetoxyborohydride
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α-Amidoalkylphenyl sulfones are stable precursors of reactive N-acylimines and can be fully reduced to the corresponding secondary amines using sodium acetoxyborohydride in dioxane at reflux.
- Mataloni, Michela,Petrini, Marino,Profeta, Roberto
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p. 1129 - 1132
(2007/10/03)
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