- Simplified preparation of a graphene-co-shelled Ni/NiO@C nano-catalyst and its application in theN-dimethylation synthesis of amines under mild conditions
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The development of Earth-abundant, reusable and non-toxic heterogeneous catalysts to be applied in the pharmaceutical industry for bio-active relevant compound synthesis remains an important goal of general chemical research.N-methylated compounds, as one of the most essential bioactive compounds, have been widely used in the fine and bulk chemical industries for the production of high-value chemicals. Herein, an environmentally friendly and simplified method for the preparation of graphene encapsulated Ni/NiO nanoalloy catalysts (Ni/NiO@C) was developed for the first time, for the highly selective synthesis ofN-methylated compounds using various functional amines and aldehydes under easy to handle, and industrially applicable conditions. A large number of primary and secondary amines (more than 70 examples) could be converted to the correspondingN,N-dimethylamines with the participation of different functional aldehydes, with an average yield of over 95%. A gram-scale synthesis also demonstrated a similar yield when compared with the benchmark test. In addition, it was further proved that the catalyst could easily be recycled because of its intrinsic magnetism and reused up to 10 times without losing its activity and selectivity. Also, for the first time, the tandem synthesis ofN,N-dimethylamine products in a one-pot process, using only a single earth-abundant metal catalyst, whose activity and selectivity were more than 99% and 94%, respectively, for all tested substrates, was developed. Overall, the advantages of this newly developed method include operational simplicity, high stability, easy recyclability, cost-effectiveness of the catalyst, and good functional group compatibility for the synthesis ofN-methylation products as well as the industrially applicable tandem synthesis process.
- Liu, Jianguo,Ma, Longlong,Song, Yanpei,Zhang, Mingyue,Zhuang, Xiuzheng
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supporting information
p. 4604 - 4617
(2021/06/30)
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- Deoxygenative hydroboration of primary, secondary, and tertiary amides: Catalyst-free synthesis of various substituted amines
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Transformation of relatively less reactive functional groups under catalyst-free conditions is an interesting aspect and requires a typical protocol. Herein, we report the synthesis of various primary, secondary, and tertiary amines through hydroboration of amides using pinacolborane under catalyst-free and solvent-free conditions. The deoxygenative hydroboration of primary and secondary amides proceeded with excellent conversions. The comparatively less reactive tertiary amides were also converted to the corresponding N,N-diamines in moderate yields under catalyst-free conditions, although alcohols were obtained as a minor product.
- An, Duk Keun,Jaladi, Ashok Kumar,Kim, Hyun Tae,Yi, Jaeeun
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- Zirconium-hydride-catalyzed site-selective hydroboration of amides for the synthesis of amines: Mechanism, scope, and application
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Developing mild and efficient catalytic methods for the selective synthesis of amines is a longstanding research objective. In this respect, catalytic deoxygenative amide reduction has proven to be promising but challenging, as this approach necessitates selective C–O bond cleavage. Herein, we report the selective hydroboration of primary, secondary, and tertiary amides at room temperature catalyzed by an earth-abundant-metal catalyst, Zr-H, for accessing diverse amines. Various readily reducible functional groups, such as esters, alkynes, and alkenes, were well tolerated. Furthermore, the methodology was extended to the synthesis of bio- and drug-derived amines. Detailed mechanistic studies revealed a reaction pathway entailing aldehyde and amido complex formation via an unusual C–N bond cleavage-reformation process, followed by C–O bond cleavage.
- Han, Bo,Jiao, Haijun,Wu, Lipeng,Zhang, Jiong
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p. 2059 - 2067
(2021/09/02)
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- Palladium-Catalyzed Reductive Aminocarbonylation of Benzylammonium Triflates with o-Nitrobenzaldehydes for the Synthesis of 3-Arylquinolin-2(1 H)-ones
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A palladium-catalyzed straightforward procedure for the synthesis of 3-arylquinolin-2(1H)-ones has been developed. The synthesis proceeds through a palladium-catalyzed reductive aminocarbonylation reaction of benzylic ammonium triflates with o-nitrobenzaldehydes, and a wide range of 3-arylquinolin-2(1H)-ones was obtained in moderate to good yields with very good functional group compatibility.
- Liu, Yongzhu,Qi, Xinxin,Wu, Xiao-Feng
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p. 13824 - 13832
(2021/10/12)
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- Electrochemical Dehydrogenative Imidation of N-Methyl-Substituted Benzylamines with Phthalimides for the Direct Synthesis of Phthalimide-Protected gem-Diamines
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A general and green electrochemical dehydrogenative method for the imidation of N-methyl benzylamines with phthalimides with excellent regioselectivities is reported for the first time. This operationally simple method offers a valuable tool to obtain str
- Lian, Fei,Sun, Caocao,Xu, Kun,Zeng, Chengchu
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supporting information
p. 156 - 159
(2019/01/11)
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- Complex Boron-Containing Molecules through a 1,2-Metalate Rearrangement/anti-SN2′ Elimination/Cycloaddition Reaction Sequence
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The three-component coupling of benzylamines, boronic esters, and 4-phenyl-3 H -1,2,4-triazole-3,5(4 H)-dione (PTAD) is reported. The boronate complex formed from an ortho -lithiated benzylamine and a boronic ester undergoes a stereospecific 1,2-metalate rearrangement/ anti -S N 2′ elimination in the presence of an N-activator to provide a dearomatized tertiary boronic ester. Interception of this dearomatized intermediate with a dienophile leads to stereopredictable cycloaddition reactions to generate highly complex three-dimensional boron-containing molecular structures. When enantioenriched α-methyl-substituted benzylamines are employed, the corresponding cycloaddition adducts are formed with excellent enantiospecificities.
- Tillin, Chloe,Bigler, Raphael,Calo-Lapido, Renata,Collins, Beatrice S.L.,Noble, Adam,Aggarwal, Varinder K.
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supporting information
p. 449 - 453
(2019/02/26)
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- Selective synthesis of mono- and di-methylated amines using methanol and sodium azide as C1 and N1 sources
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A Ru(ii) complex mediated synthesis of various N,N-dimethyl and N-monomethyl amines from organic azides using methanol as a methylating agent is reported. This methodology was successfully applied for a one-pot reaction of bromide derivatives and sodium azide in methanol. Notably, by controlling the reaction time several N-monomethylated and N,N-dimethylated amines were synthesized selectively. The practical applicability of this tandem process was revealed by preparative scale reactions with different organic azides and synthesis of an anti-vertigo drug betahistine. Several kinetic experiments and DFT studies were carried out to understand the mechanism of this transformation.
- Chakrabarti, Kaushik,Mishra, Anju,Panja, Dibyajyoti,Paul, Bhaskar,Kundu, Sabuj
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supporting information
p. 3339 - 3345
(2018/07/29)
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- Direct Synthesis of N,N-Dimethylated and β-Methyl N,N-Dimethylated amines from nitriles using methanol: Experimental and computational studies
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Direct and selective synthesis of N,N-dimethylated amines from nitriles using methanol as C1 building blocks is reported using an air- and moisture-stable ruthenium complex. Following this process, various aromatic as well as aliphatic nitriles were converted to the corresponding N-methylated amines. Interestingly, tandem C-methylation as well as N-methylation was achieved by introducing multiple methyl groups. The practical aspect of this process was revealed by preparative-scale reactions with different nitriles and the synthesis of anti-allergic drug "avil". Several kinetic experiments and detailed DFT calculations were carried out to understand the mechanism of this process.
- Paul, Bhaskar,Shee, Sujan,Panja, Dibyajyoti,Chakrabarti, Kaushik,Kundu, Sabuj
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p. 2890 - 2896
(2018/04/14)
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- Lewis Acid-Catalyzed Reductive Amination of Aldehydes and Ketones with N,N-Dimethylformamide as Dimethylamino Source, Reductant and Solvent
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A practical zinc acetate dihydrate-catalyzed reductive amination of various carbonyl compounds with N,N-dimethylformamide (DMF) as dimethylamino (Me2N) source, reductant and solvent has been developed. This reaction shows broad substrate scope,
- Yang, Luo,Lin, Jie,Kang, Lei,Zhou, Wang,Ma, Da-You
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supporting information
p. 485 - 490
(2018/01/15)
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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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- Enantiospecific Synthesis of ortho-Substituted Benzylic Boronic Esters by a 1,2-Metalate Rearrangement/1,3-Borotropic Shift Sequence
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Coupling reactions between benzylamines and boronic esters have been investigated. ortho-Lithiated benzylamines react with boronic esters and a N-activator to afford ortho-substituted benzylic boronic esters with formal 1,1′-benzylidene insertion into the C-B bond. The reaction occurs by a SN2′ elimination and 1,2-metalate rearrangement of the N-activated boronate complex to afford a dearomatized intermediate, which undergoes a Lewis-acid catalyzed 1,3-borotropic shift to afford the boronic ester products in high yield and with excellent enantiospecificity. The use of enantioenriched α-substituted benzylamines gave the corresponding secondary boronic esters with high ee.
- Aichhorn, Stefan,Bigler, Raphael,Myers, Eddie L.,Aggarwal, Varinder K.
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supporting information
p. 9519 - 9522
(2017/07/25)
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- Efficient Cobalt-Catalyzed Methylation of Amines Using Methanol
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The methylation of amines using methanol is a promising route to synthesize N-methylamines, and the development of cheap and efficient catalytic system for this reaction is of great significance. Herein, we reported a cobalt (Co)-based catalytic system, which was in situ formed from commercially available Co precursor and a tetradentate phosphine ligand P(CH2CH2PPh2)3 combined with K3PO4. This catalystic system was very effective for the selective production of dimethylated products from aliphatic amines and monomethylated ones from aromatic amines. The reaction mechanism was further investigated by control and isotope labelling experiments. (Figure presented.).
- Liu, Zhenghui,Yang, Zhenzhen,Yu, Xiaoxiao,Zhang, Hongye,Yu, Bo,Zhao, Yanfei,Liu, Zhimin
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supporting information
p. 4278 - 4283
(2017/10/23)
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- Ionic liquid/H2O-mediated synthesis of mesoporous organic polymers and their application in methylation of amines
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Mesoporous Tr?ger's base-functionalized polymers (Meso-TBPs) were prepared using a sulfonic acid group functionalized ionic liquid/H2O system, with surface areas up to 431 m2 g-1 and pore sizes of 3-15 nm. Ir(ii) coordinated Meso-TBPs exhibited extraordinary catalytic performance in the N-methylation of amines using methanol.
- Yu, Xiaoxiao,Yang, Zhenzhen,Zhang, Hongye,Yu, Bo,Zhao, Yanfei,Liiu, Zhenghui,Ji, Guipeng,Liu, Zhimin
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supporting information
p. 5962 - 5965
(2017/07/10)
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- N-Alkyl Interstitial Spacers and Terminal Pendants Influence the Alkaline Stability of Tetraalkylammonium Cations for Anion Exchange Membrane Fuel Cells
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Current performance targets for anion exchange membrane (AEM) fuel cells call for greater than 95% alkaline stability for 5000 h at temperatures of up to 120 °C. Using this target temperature of 120 °C, we provide an incisive 1H nuclear magnetic resonance-based alkaline degradation method to identify the degradation products of n-alkyl spacer tetraalkylammonium cations in various AEM polymers and small molecule analogues. The operative alkaline degradation mechanisms and rates on benzyltrimethylammonium-, n-alkyl interstitial spacer-, and n-alkyl terminal chain-cations are compared in several architectures. Our findings indicate that benzyltrimethylammonium and n-alkyl terminal pendant cations are significantly more labile than an n-alkyl interstitial spacer cation. Additionally, we found that the alkaline stability of an n-alkyl interstitial spacer cation is enhanced when it is combined with an n-alkyl terminal pendant. At 120 °C, an inverse trend was observed in the overall stability of AEM poly(styrene) and AEM poly(phenylene oxide) samples compared to what has been shown at 80 °C. Follow-up small molecule studies suggest that at 120 °C, a 1,4-elimination degradation mechanism may be activated on styrenic AEM polymers capable of forming hyperconjugated resonance hybrids.
- Nu?ez, Sean A.,Capparelli, Clara,Hickner, Michael A.
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p. 2589 - 2598
(2016/06/01)
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- PROCESS FOR PRODUCING N-METHYL OR N,N-DIMETYL AMINES
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A process for producing N-methyl or N,N-dimethyl amines, which comprises using amine compound, nitro-containing compound or nitrile compound as a starting material, carbon dioxide as a methylating agent and hydrogen gas as a reducing agent, and allowing them to react in a sealed reactor for 6 to 48 h in a reaction medium at a reaction temperature of 80 to 180 ° C. in the presence of a composite catalyst, so as to provide N-methyl or N,N-dimethyl amines. The process of the present invention is simple and under relative mild reaction conditions. By means of the process of the invention, the target products can be prepared at low cost with a high yield. The catalysts used have a high catalytic activity and can be separated from the reaction system simply and reused. Furthermore, the whole process of the present invention is environmental-friendly and facilitates the cycling use of carbon dioxide.
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Paragraph 0059
(2015/02/18)
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- Light-promoted N,N-dimethylation of amine and nitro compound with methanol catalyzed by Pd/TiO2 at room temperature
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A series of TiO2 supported nano-Pd catalysts (Pd/TiO2) were prepared and used for the N,N-dimethylation of different amines and nitro compounds with methanol under UV irradiation at room temperature. A wide range of N,N-dimethyl amines were one-pot synthesized with up to 98% by applying aliphatic secondary amines, aromatic primary amines, aliphatic primary amines and aromatic nitro compounds as starting materials. It is noteworthy that up to 90% yield of 4-chloro-N,N-dimethylaniline was obtained by adjusting the Pd loadings on the TiO2 and the dehalogenation reaction was inhibited. Finally, a reaction mechanism is discussed, involving PhN = CH2 and PhNHCH3 as reaction intermediates.
- Zhang, Lina,Zhang, Yan,Deng, Youquan,Shi, Feng
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p. 14514 - 14521
(2015/03/05)
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- Dual antitumor and antiangiogenic activity of organoplatinum(II) complexes
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A library of over 20 cycloplatinated compounds of the type [Pt(dmba-R)LCl] (dmba-R = C,N-dimethylbenzylamine-like ligand; R being MeO, Me, H, Br, F, CF3, and NO2 substituents in the R5 or R4 position of the phenyl ring; L = DMSO and P(C6H4CF3-p)3) has been prepared. All compounds are active in both human ovarian carcinoma A2780 cells and cisplatin-resistant A2780cisR cells, with most of the DMSO platinum complexes exhibiting IC50 values in the submicromolar range in the A2780 cell line. Interestingly, DMSO platinum complexes show low cytotoxicity in the nontumorigenic kidney cell line BGM and therefore high selectivity factors SF. In addition, some of the DMSO platinum complexes effectively inhibit angiogenesis in the human umbilical vein endothelial cell line EA.hy926. These are the first platinum(II) complexes reported to inhibit angiogenesis at a close concentration to their IC50 in A2780 cells, turning them into dual cytotoxic and antiangiogenic compounds.
- Zamora, Ana,Pérez, Sergio A.,Rodríguez, Venancio,Janiak, Christoph,Yellol, Gorakh S.,Ruiz, José
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p. 1320 - 1336
(2015/03/04)
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- N-Methylation of amine and nitro compounds with CO2/H2 catalyzed by Pd/CuZrOx under mild reaction conditions
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An active Pd/ZrCuOx catalyst was prepared for the reductive amination of CO2. The N-methylation of amines and nitro compounds with CO2/H2 can be realized with up to 97% yield under relatively mild reaction condi
- Cui, Xinjiang,Zhang, Yan,Deng, Youquan,Shi, Feng
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supporting information
p. 13521 - 13524
(2015/01/09)
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- Methylation of amines, nitrobenzenes and aromatic nitriles with carbon dioxide and molecular hydrogen
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CO2/H2 was successfully employed in alkylation reactions by performing CO2 reduction and amine N-methylation in one-pot. In the presence of a simple CuAlOx catalyst, N-methyl or N,N-dimethyl amines with different structures can be selectively synthesized with up to 96% yields by applying amine, nitrobenzene and nitrile as starting materials.
- Cui, Xinjiang,Dai, Xingchao,Zhang, Yan,Deng, Youquan,Shi, Feng
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p. 649 - 655
(2014/01/17)
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- Cu(II)-promoted palladium-catalyzed C-H ortho-arylation of N, N-dimethylbenzylamines
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A novel protocol for palladium-catalyzed arylation of the C(sp 2)-H bond directed by a N,N-dimethylaminomethyl group in the presence of AgOAc and Cu(OAc)2·H2O is described. Various aryl iodides proved to be efficient coupl
- Feng, Ruokun,Yao, Jinzhong,Liang, Zunjun,Liu, Zhanxiang,Zhang, Yuhong
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p. 3688 - 3696
(2013/06/04)
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- LiCl-Promoted Pd(ii)-catalyzed ortho carbonylation of N,N- dimethylbenzylamines
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Palladium-catalyzed highly regioselective carbonylation of substituted N,N-dimethylbenzylamines with the assistance of LiCl was developed. The ortho-functionalized N,N-dimethylbenzylamine was further transformed into ortho-methyl benzoate under mild conditions. These two transformations could be combined into one pot to produce the desired product in moderate yield. Applications of this methodology to synthesize the fragments of variolaric acid were also studied.
- Li, Hu,Cai, Gui-Xin,Shi, Zhang-Jie
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supporting information; experimental part
p. 10442 - 10446
(2011/01/08)
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- Indirect ortho functionalization of substituted toluenes through ortho olefination of N,N-dimethylbenzylamines tuned by the acidity of reaction conditions
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Highly regioselective olefination of substituted N,N-dimethylbenzylamines was developed by tuning the acidity of reaction conditions based on analysis of their features. The ortho-functionalized N,N-dimethylbenzylamines were further transformed into 3-(2′
- Cai, Guixin,Fu, Ye,Li, Yizhou,Wan, Xiaobing,Shi, Zhangjie
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p. 7666 - 7673
(2008/02/09)
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- Lewis acid-catalyzed reductive amination of carbonyl compounds with aminohydrosilanes
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The TiCl4-catalyzed reaction of aromatic carbonyl compounds with (dialkylamino)dimethylsilanes gave tertiary amines in moderate to high yields. The reductive amination of aliphatic aldehydes was effectively catalyzed by ZnI2. Methyl
- Miura,Ootsuka,Suda,Nishikori,Hosomi
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p. 1617 - 1619
(2007/10/03)
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- MANNICH REACTIONS OF ARYLTRIALKYLSTANNANES IN APROTIC SOLVENTS
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Aryltributyl- and aryltrimethyl-stannanes react with a range of N,N-dialkylmethylene-imonium salts to afford N,N-dialkylaminomethyl derivatives in good yields.The method can be used to obtain regioisomers that are not available using classical procedures. "In situ" reactions can also be carried out using alkoxydialkylaminomethanes (aminol ethers) and bis(dialkylamino)methanes (aminals) together with chlorotrimethyl- and trichloromethyl-silanes as the source of the electrophile.However, the "in situ" reactions do not afford good yields in the majority of cases, as a result of the inhibition of imonium salt formation by trialkylchlorostannane.
- Cooper, Mark S.,Fairhurst, Robin A.,Heaney, Harry,Papageorgiou, George,Wilkins, Robert F.
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p. 1155 - 1166
(2007/10/02)
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- Thermodynamics, kinetics, and mechanism of exchange of cyclopalladated ligands
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The exchange between cyclopalladated complexes and free ligands has been studied in acetic acid. An equilibrium study of the system based on N,N-dimethylbenzylamine derivatives [PdX(YZC6H2CH2NMe2)]2 + 2C6D5CD2NMe2 ? [PdX-(C6D4CD2NMe2)]2 + 2YZC6H2DCH2NMe2 (K1) has revealed that Pd(II) binds preferably with the electron-poorest ligand at equilibrium; K1 is 114, 0.59, 0.125, 0.008, and 0.0034 for 4-Y (5-Z) = MeO (MeO), H (Me), H (H), H (Cl), and H (NO2), respectively, at 55°C in D3CCOOD/CDCl3, X = MeCO2-. A procedure for regioselective ortho palladation of bifunctional derivatives such as 1-(3,4-dimethoxyphenyl)-2-methyl-3-(4-nitrophenyl)-2-azapropane (7) is put forward. In aprotic chloroform, Pd(II) acetate metalates the electron-rich ring of 7 to yield 8a, but the electron-poor ring is ortho palladated in acetic acid to yield 9a. A dissociative exchange mechanism is proposed on the basis of a kinetic study of reactions between [PdX-(YZC6H2CH2NMe2)]2 and 2-phenylpyridine or azobenzene to afford the corresponding cyclopalladated complexes. Preequilibrium measurements have indicated that in the former case the reactive species are monomers formed via acetate-bridge cleavage by 2-phenylpyridine but in the latter case the complexes react as dimers. Despite this, all of the reactions are first order in complex and zero order in entering ligand. The rate constants of the 2-phenylpyridine case at 75°C are (104k) 12.6, 3.9, 2.35, 2.6, 0.44, and 0.0225 s-1 for 4-Y (5-Z) = MeO (MeO), H (Me), H (H), H (MeO), H (Cl), and H (NO2), respectively. On the basis of substituent and solvent kinetics isotope effects, values of activation parameters, and data obtained previously, it has been suggested that cleavage of the Pd-N bond of the leaving ligand occurs first, followed by acidolysis of the Pd-C bond. Both steps can contribute to the overall rate. The two are followed by the rapid activation of the C-H bond of the incoming ligand. Reasons for the pseudonucleophilic behavior of Pd(II) toward C-H bonds of benzylamines in acetic acid have been evaluated on the basis of the proposed mechanism.
- Ryabov, Alexander D.
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p. 1252 - 1260
(2008/10/08)
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- MANNICH REACTIONS OF ARYL-TRIALKYLSTANNANES USING PREFORMED DIALKYL-METHYLENEIMINIUM SALTS
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Dialkyl-methyleneiminium salts react with aryl-tributyl- and aryl-trimethylstannanes to afford the corresponding N,N-dialkylaminomethyl- derivatives in good yields.The method can be used to obtain isomers that are not obtained by classical procedures.
- Cooper, Mark S.,Heaney Harry
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p. 5011 - 5014
(2007/10/02)
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