- Additive-free selective methylation of secondary amines with formic acid over a Pd/In2O3 catalyst
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Formic acid is used as the sole carbon and hydrogen source in the methylation of aromatic and aliphatic amines to methylamines. The reaction proceeds via a formylation/transfer hydrogenation pathway over a solid Pd/In2O3 catalyst without the need for any additive.
- Benaissa, Idir,Cantat, Thibault,Genre, Caroline,Godou, Timothé,Pinault, Mathieu
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- Boosting Mass Exchange between Pd/NC and MoC/NC Dual Junctions via Electron Exchange for Cascade CO2 Fixation
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Merging existing catalysts together as a cascade catalyst may achieve one-pot synthesis of complex but functional molecules by simplifying multistep reactions, which is the blueprint of sustainable chemistry with low pollutant emission and consumption of energy and materials only when the smooth mass exchange between different catalysts is ensured. Effective strategies to facilitate the mass exchange between different active centers, which may dominate the final activity of various cascade catalysts, have not been reached until now, even though charged interfaces due to work function driven electron exchange have been widely observed. Here, we successfully constructed mass (reactants and intermediates) exchange paths between Pd/N-doped carbon and MoC/N-doped carbon induced by interfacial electron exchange to trigger the mild and cascade methylation of amines using CO2and H2. Theoretical and experimental results have demonstrated that the mass exchange between electron-rich MoC and electron-deficient Pd could prominently improve the production of N,N-dimethyl tertiary amine, which results in a remarkably high turnover frequency value under mild conditions, outperforming the state-of-the-art catalysts in the literature by a factor of 5.9.
- Chen, Jie-Sheng,Li, Qi-Yuan,Li, Xin-Hao,Lin, Xiu,Xia, Si-Yuan,Xu, Dong,Zhai, Guang-Yao,Zhang, Shi-Nan
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supporting information
(2022/03/15)
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- Reductive amination of ketones/aldehydes with amines using BH3N(C2H5)3as a reductant
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Herein, we report the first example of efficient reductive amination of ketones/aldehydes with amines using BH3N(C2H5)3 as a catalyst and a reductant under mild conditions, affording various tertiary and secondary amines in excellent yields. A mechanistic study indicates that BH3N(C2H5)3 plays a dual function role of promoting imine and iminium formation and serving as a reductant in reductive amination. This journal is
- Zou, Qizhuang,Liu, Fei,Zhao, Tianxiang,Hu, Xingbang
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supporting information
p. 8588 - 8591
(2021/09/04)
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- Degradation of Organic Cations under Alkaline Conditions
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Understanding the degradation mechanisms of organic cations under basic conditions is extremely important for the development of durable alkaline energy conversion devices. Cations are key functional groups in alkaline anion exchange membranes (AAEMs), and AAEMs are critical components to conduct hydroxide anions in alkaline fuel cells. Previously, we have established a standard protocol to evaluate cation alkaline stability within KOH/CD3OH solution at 80 °C. Herein, we are using the protocol to compare 26 model compounds, including benzylammonium, tetraalkylammonium, spirocyclicammonium, imidazolium, benzimidazolium, triazolium, pyridinium, guanidinium, and phosphonium cations. The goal is not only to evaluate their degradation rate, but also to identify their degradation pathways and lead to the advancement of cations with improved alkaline stabilities.
- You, Wei,Hugar, Kristina M.,Selhorst, Ryan C.,Treichel, Megan,Peltier, Cheyenne R.,Noonan, Kevin J. T.,Coates, Geoffrey W.
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supporting information
p. 254 - 263
(2020/12/23)
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- Germyliumylidene: A Versatile Low Valent Group 14 Catalyst
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Bis-NHC stabilized germyliumylidenes [RGe(NHC)2]+ are typically Lewis basic (LB) in nature, owing to their lone pair and coordination of two NHCs to the vacant p-orbitals of the germanium center. However, they can also show Lewis acidity (LA) via Ge?CNHC σ* orbital. Utilizing this unique electronic feature, we report the first example of bis-NHC-stabilized germyliumylidene [MesTerGe(NHC)2]Cl (1), (MesTer=2,6-(2,4,6-Me3C6H2)2C6H3; NHC= IMe4=1,3,4,5-tetramethylimidazol-2-ylidene) catalyzed reduction of CO2 with amines and arylsilane, which proceeds via its Lewis basic nature. In contrast, the Lewis acid nature of 1 is utilized in the catalyzed hydroboration and cyanosilylation of carbonyls, thus highlighting the versatile ambiphilic nature of bis-NHC stabilized germyliumylidenes.
- Sarkar, Debotra,Dutta, Sayan,Weetman, Catherine,Schubert, Emeric,Koley, Debasis,Inoue, Shigeyoshi
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supporting information
p. 13072 - 13078
(2021/08/09)
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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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p. 1722 - 1729
(2021/04/19)
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- Selective: N-formylation/N-methylation of amines and N-formylation of amides and carbamates with carbon dioxide and hydrosilanes: Promotion of the basic counter anions of the zinc catalyst
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A catalyst composed of commercially available Zn(OAc)2 and 1,10-phenanthroline (phen) was effective in the N-formylation/N-methylation of amines using CO2 as the C1 source in the presence of hydrosilanes. An equimolar reaction of N-methylaniline with PhSiH3 under a CO2 atmosphere yielded the N-formylation product in 92% yield at 25 °C. Scale-up of the reaction using 10 mmol substrate was also successful in affording the desired product in 83% yield (1.1 g). This catalyst exhibits a high thermal stability and a turnover number (TON) of 385000 at 150 °C. In addition, the reaction of N-methylaniline in the presence of excess Ph2SiH2 produced N,N-dimethylaniline. Furthermore, our catalytic protocol was developed for the N-formylation of amides and carbamates, which have smaller pKa values and lower reactivities than the corresponding amines. The present Zn(OAc)2/phen catalyst was found to show versatility in the conversion of CO2 and amines into several functionalized organic chemicals under mild conditions. We propose that the basic counter anion (i.e., the acetate) of the catalyst activates both the Si-H and N-H bonds.
- Zhang, Qiao,Lin, Xiao-Tao,Fukaya, Norihisa,Fujitani, Tadahiro,Sato, Kazuhiko,Choi, Jun-Chul
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supporting information
p. 8414 - 8422
(2020/12/29)
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- N-Heterocyclic Carbene-Stabilized Germa-acylium Ion: Reactivity and Utility in Catalytic CO2Functionalizations
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The first acceptor-free heavier germanium analogue of an acylium ion, [RGe(O)(NHC)2]X (R = MesTer = 2,6-(2,4,6-Me3C6H2)2C6H3; NHC = IMe4 = 1,3,4,5-tetramethylimidazol-2-ylidene; X = (Cl or BArF = {(3,5-(CF3)2C6H5)4B}), was isolated by reacting [RGe(NHC)2]X with N2O. Conversion of the germa-acylium ion to the first solely donor-stabilized germanium ester [(NHC)RGe(O)(OSiPh3)] and corresponding heavier analogues ([RGe(S)(NHC)2]X and [RGe(Se)(NHC)2]X) demonstrated its classical acylium-like behavior. The polarized terminal GeO bond in the germa-acylium ion was utilized to activate CO2 and silane, with the former found to be an example of reversible activation of CO2, thus mimicking the behavior of transition metal oxides. Furthermore, its transition-metal-like nature is demonstrated as it was found to be an active catalyst in both CO2 hydrosilylation and reductive N-functionalization of amines using CO2 as the C1 source. Mechanistic studies were undertaken both experimentally and computationally, which revealed that the reaction proceeds via an N-heterocyclic carbene (NHC) siloxygermylene [(NHC)RGe(OSiHPh2)].
- Sarkar, Debotra,Weetman, Catherine,Dutta, Sayan,Schubert, Emeric,Jandl, Christian,Koley, Debasis,Inoue, Shigeyoshi
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supporting information
p. 15403 - 15411
(2020/10/20)
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- Electroactivated alkylation of amines with alcohols: Via both direct and indirect borrowing hydrogen mechanisms
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A green, efficient N-alkylation of amines with simple alcohols has been achieved in aqueous solution via an electrochemical version of the so-called "borrowing hydrogen methodology". Catalyzed by Ru on activated carbon cloth (Ru/ACC), the reaction works well with methanol, and with primary and secondary alcohols. Alkylation can be accomplished by either of two different electrocatalytic processes: (1) in an undivided cell, alcohol (present in excess) is oxidized at the Ru/ACC anode; the aldehyde or ketone product condenses with the amine; and the resulting imine is reduced at an ACC cathode, combining with protons released by the oxidation. This process consumes stoichiometric quantities of current. (2) In a membrane-divided cell, the current-activated Ru/ACC cathode effects direct C-H activation of the alcohol; the resulting carbonyl species, either free or still surface-adsorbed, condenses with amine to form imine and is reduced as in (1). These alcohol activation processes can alkylate primary and secondary aliphatic amines, as well as ammonia itself at 25-70 °C and ambient pressure.
- Appiagyei, Benjamin,Bhatia, Souful,Keeney, Gabriela L.,Dolmetsch, Troy,Jackson, James E.
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supporting information
p. 860 - 869
(2020/02/21)
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- Diverse catalytic reactivity of a dearomatized PN3P?-nickel hydride pincer complex towards CO2 reduction
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A dearomatized PN3P?-nickel hydride complex has been prepared using an oxidative addition process. The first nickel-catalyzed hydrosilylation of CO2 to methanol has been achieved, with unprecedented turnover numbers. Selective methylation and formylation of amines with CO2 were demonstrated by such a PN3P?-nickel hydride complex, highlighting its versatile functions in CO2 reduction.
- Li, Huaifeng,Gon?alves, Théo P.,Zhao, Qianyi,Gong, Dirong,Lai, Zhiping,Wang, Zhixiang,Zheng, Junrong,Huang, Kuo-Wei
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supporting information
p. 11395 - 11398
(2018/10/20)
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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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- Deoxygenation of tertiary amine N-oxides under metal free condition using phenylboronic acid
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A simple and efficient method for the deoxygenation of amine N-oxides to corresponding amines is reported using the green and economical reagent phenylboronic acid. Deoxygenation of N,N-dialkylaniline N-oxides, trialkylamine N-oxides and pyridine N-oxides were achieved in good to excellent yields. The reduction susceptible functional groups such as ketone, amide, ester and nitro groups are well tolerated with phenylboronic acid during the deoxygenation process even at high temperature. In addition, an indirect method for identification and quantification of tert-amine N-oxide is demonstrated using UV–Vis spectrometry which may be useful for drug metabolism studies.
- Gupta, Surabhi,Sureshbabu, Popuri,Singh, Adesh Kumar,Sabiah, Shahulhameed,Kandasamy, Jeyakumar
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supporting information
p. 909 - 913
(2017/02/15)
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- N-Methylation of Amines with Methanol Catalyzed by a Cp?Ir Complex Bearing a Functional 2,2′-Bibenzimidazole Ligand
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A new type of Cp?Ir complex bearing a functional 2,2′-bibenzimidazole ligand was designed, synthesized, and found to be a highly effective and general catalyst for the N-methylation of a variety of amines with methanol in the presence of a weak base (0.3 equiv of Cs2CO3).
- Liang, Ran,Li, Shun,Wang, Rongzhou,Lu, Lei,Li, Feng
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supporting information
p. 5790 - 5793
(2017/11/10)
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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 0034-0035
(2017/08/29)
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- N-heterocyclic carbene copper(i) catalysed N-methylation of amines using CO2
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The N-methylation of amines using CO2 and PhSiH3 as source of CH3 was efficiently performed using a N-heterocyclic carbene copper(i) complex. The methodology was found compatible with aromatic and aliphatic primary and secondary amines. Synthetic and computational studies have been carried out to support the proposed reaction mechanism for this transformation.
- Santoro, Orlando,Lazreg, Fama,Minenkov, Yury,Cavallo, Luigi,Cazin, Catherine S. J.
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p. 18138 - 18144
(2015/10/28)
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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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- METHOD OF PRODUCING TERTIARY AMINE OR TERTIARY AMINE DERIVATIVE
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PROBLEM TO BE SOLVED: To provide a method of producing tertiary amine or tertiary amine derivative with high selectivity. SOLUTION: In the method of producing tertiary amine or tertiary amine derivative, a reaction system including: an organic chemical raw material containing at least one kind of group selected from -NH2, -NH2 HCl, >NH and >NH HCl, a nitrogen atom contained in the group bounding to a carbon atom; aliphatic alcohol having 1 to 20 carbon atoms; and a catalyst where a carrier containing titanium oxide carries a silver component (metal silver or silver compound), is irradiated with light, and the group in the organic compound raw material is converted to -NR02 or >NR0, ( R0 is an aliphatic hydrocarbon group having 1 to 20 carbon atoms derived from the aliphatic alcohol). The percentage content of the silver in the catalyst is 0.5 to 10 mass% with respect to the titanium oxide. COPYRIGHT: (C)2015,JPOandINPIT
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Paragraph 0066; 0070; 0071
(2018/10/31)
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- Reductive methylation of primary and secondary amines and amino acids by aqueous formaldehyde and zinc
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Amines can be methylated when treated with formaldehyde and zinc in aqueous medium. Selective mono- or dimethylation can be achieved by proper choice of pH, stoichiometry and reaction time. This method can also be applied for amino acids.
- da Silva, Renato A.,Estevam, Idália H.S.,Bieber, Lothar W.
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p. 7680 - 7682
(2008/03/30)
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- Cyclopentadienyl RuII Complexes as Highly Efficient Catalysts for the N-Methylation of Alkylamines by Methanol
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The ruthenium(II) half-sandwich complex [RuCl(η5-C5H5)(PPh3)2] (1) catalyses the reaction between methanol and alkylamines RNH2 or R1R2NH to afford RN(CH3)2 and R1R2NCH3 products, respectively. The reaction is quantitative and generally fast, at the methanol reflux temperature, for a wide spectrum of substrates. Starting form primary amines, the stepwise formation of RN=CH2, RNHCH3, and RN(CH3)2 has been observed. Both PPh3 and Cl- dissociation from 1 are key-steps in forming the effective catalytic species. The catalytic activity of several half-sandwich neutral or cationic complexes (2-15) related to 1 is also discussed.
- Zotto, Alessandro Del,Baratta, Walter,Sandri, Mauro,Verardo, Giancarlo,Rigo, Pierluigi
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p. 524 - 529
(2007/10/03)
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- Process for the synthesis of N-methyl-dialkylamines from secundary amines and formaldehyde
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Production of N-methyldialkylamines comprises reacting a dialkylamine with 1.5-3 molar equivalents of formaldehyde at 100-200[deg]C; degassing the reaction product; separating the aqueous phase; and distilling the organic phase.
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Page column 7
(2008/06/13)
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- Butyltriphenylphosphonium tetraborate (BTPPTB) as a selective reducing agent for the reduction of imines, enamines and oximes and reductive alkylation of aldehydes or ketones with primary amines in methanol or under solid-phase conditions
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Butyltriphenylphosphonium tetraborate (BTPPTB) 1, generated as white solid from butyltriphenylphosphonium bromide and sodium borohydride, is found to be a selective and versatile reducing agent. The reagent in methanol or under solvent-free conditions is very useful for the reduction of imines, enamines and oximes or reductive amination of aldehydes and ketones. Under solvent-free conditions the reactions are faster and the yields of the products are higher.
- Hajipour,Mohammadpoor-Baltork,Noroallhi
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p. 152 - 156
(2007/10/03)
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- New insights into the chemistry of lithium carbamoyls: Characterization of an adduct (R2NC(O)CLi(OLi)NR2)
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Studies of the reaction of lithium dicyclohexylamide with N,N- dibutylformamide, 1-formylpiperidine, and 4-formylmorpholine indicate that the equilibria resulting from these compounds are shifted toward the formation of an adduct, which quickly collapses to dicyclohexylamine and the lithiated carbamoyl anion derived from the initial disubstituted formamide. Further reactions of the lithium carbamoyl lead to a new adduct where a lithiated carbon is bounded to N, O, and a carbonyl functionality. The 13C NMR analysis of the reaction mixtures showed the presence of similar intermediates in all cases: adducts of this type have not been reported before. These dilithiated intermediates were trapped with methyl iodide giving the corresponding doubly methylated derivatives. Isolation of substituted glyoxylamides and quantitative determination of the products yields constitute further evidence of the whole reaction scheme proposed.
- Nudelman, Norma S.,Garcia Linares, Guadalupe E.
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p. 1629 - 1635
(2007/10/03)
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- Borohydride reductions in dichloromethane: A convenient, environmentally compatible procedure for the methylation of amines
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The combination of zinc chloride and sodium borohydride in dichloromethane is used to effect reductive aminations of formaldehyde with a variety of primary and secondary amines containing potentially acid-sensitive functional groups in good to excellent yields.
- Bhattacharyya
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p. 2061 - 2069
(2007/10/02)
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- Use of Zinc Borohydride in Reductive Amination: An Efficient and Mild Method for N-Methylation of Amines
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An efficient method for the reductive methylation of amines using paraformaldehyde, zinc chloride and zinc borohydride is described.
- Bhattacharyya, Sukanta,Chatterjee, Arindam,Duttachowdhury, Shiti, Kantha
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- Titanium(IV) Isopropoxide and Sodium Borohydride: A Reagent of Choice for Reductive Amination
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The preliminary results on the novel use of titanium(IV) isopropoxide and sodium borohydride in reductive amination reactions are reported.A highly efficient and mild procedure for reductive aminations of formaldehyde with a variety of primary and secondary amines is described.
- Bhattacharyya, Sukanta
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p. 2401 - 2404
(2007/10/02)
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- SODIUM HYDROGEN TELLURIDE AS A USEFUL NUCLEOPHILIC REAGENT FOR THE CLEAVAGE OF EPOXIDES AND OF QUATERNARY AMMONIUM SALTS
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Sodium hydrogen telluride opens many epoxides cleanly by an SN2 process to give telluro-alcohols, which by reduction with nickel boride afford alcohols.An intermediate telluro-alcohol was converted to olefin in high yield by treatment with p-toluene-sulphonyl chloride in pyridine.Quaternary ammonium salts are also cleaved efficiently by sodium hydrogen telluride.
- Barton, Derek H. R.,Fekih, Abdelwaheb,Lusinchi, Xavier
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p. 6197 - 6200
(2007/10/02)
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- REDUKTIVE METHYLIERUNG PRIMAERER UND SEKUNDAERER AMINE MIT HILFE VON FORMALDEHYD UND SALZEN DER PHOSPHORIGEN SAEURE
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Salts of phophorous acid were found to be useful alternative reducing agents for the reductive methylation of amines.
- Loibner, H.,Pruckner, A.,Stuetz, A.
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p. 2535 - 2536
(2007/10/02)
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- SELECTIVE CONVERSION OF PRIMARY AMINES INRO N,N-DIMETHYLALKYL- OR N,N-DIALKYLMETHYL-AMINES WITH METHANOL AND RuCl2(Ph3P)3
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N,N-dimethylalkyl- or N,N-dialkylmethyl-amines are selectively obtained from the reaction between aliphatic amines and methanol at 180 deg C for 7 h in the presence of RuCl2(Ph3P)3 catalyst.
- Arcelli, Antonio,Khai, Bui-The,Porzi, Gianni
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