- Simultaneous Preparation of (S)-2-Aminobutane and d -Alanine or d -Homoalanine via Biocatalytic Transamination at High Substrate Concentration
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(S)-2-Aminobutane, d-alanine, and d-homoalanine are important intermediates for the production of various active pharmaceutical ingredients and food additives. The preparation of these small chiral amine or amino acids with high water solubility still demands searching for efficient methods. In this work, we identified an ω-transaminase (ω-TA) from Sinirhodobacter hungdaonensis (ShdTA) that catalyzed the kinetic resolution of racemic 2-aminobutane at a concentration of 800 mM using pyruvate as the amino acceptor, leading to the simultaneous isolation of enantiopure (S)-2-aminobutane and d-alanine in 46% and 90% yield, respectively. In addition, (S)-2-aminobutane (98% ee) and d-homoalanine (99% ee) were isolated in 45% and 93% yield, respectively, in the kinetic resolution of racemic 2-aminobutane at a concentration of 400 mM coupled with deamination of l-threonine by threonine deaminase. We thus developed a biocatalytic process for the practical synthesis of these valuable small chiral amine and d-amino acids.
- Li, Jianjiong,Wang, Yingang,Wu, Qiaqing,Yao, Peiyuan,Yu, Shanshan,Zhu, Dunming
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supporting information
(2022/03/01)
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- One-pot reductive amination of carboxylic acids: a sustainable method for primary amine synthesis
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The reductive amination of carboxylic acids is a very green, efficient and sustainable method for the production of (bio-based) amines. However, with current technology, this reaction requires two to three reaction steps. Here, we report the first (heterogeneous) catalytic system for the one-pot reductive amination of carboxylic acids to amines, with solely H2 and NH3 as the reactants. This reaction can be performed with relatively cheap ruthenium-tungsten bimetallic catalysts in the green and benign solvent cyclopentyl methyl ether (CPME). Selectivities of up to 99% for the primary amine could be achieved at high conversions. Additionally, the catalyst is recyclable and tolerant for common impurities such as water and cations (e.g. sodium carboxylate).
- Coeck, Robin,De Vos, Dirk E.
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supporting information
p. 5105 - 5114
(2020/08/25)
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- Highly efficient one-pot multi-directional selective hydrogenation and N-alkylation catalyzed by Ru/LDH under mild conditions
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Atomic economy, non-toxicity, harmlessness and multidirectional selectivity advocated by green chemistry have increasingly become a hot and difficult research topic. Herein, we present a highly efficient, one-pot tandem and easy-to-operate method through which we could directly produce a broad range of multi-directional selective hydrogenated amines or N-alkyl aliphatic amines using aromatic nitro compounds as raw materials. Ru/LDH with characteristics of layered mesoporous structure, well dispersed small Ru nanoparticles and LDH stabilization to the Ru NPs was employed as the catalyst. It is remarkable that multi-directional superb chemoselectivity to aromatic amines, alicyclic amines as well as N-alkyl aliphatic amines could be achieved with excellent catalytic activity and recyclability by tuning reaction conditions over 5wt%Ru/LDH-2. Additionally, this catalytic system also exhibited attractive activity and multi-directional chemoselectivity in the hydrogenation of quinoline and its derivatives with solvents of different polarity. Chemoselectivity to 5,6,7,8-tetrahydroquinoline derivatives could reach as high as 95.6 %.
- Zhang, Sishi,Xu, Jie,Cheng, Hongmei,Zang, Cuicui,Sun, Bin,Jiang, Heyan,Bian, Fengxia
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supporting information
(2020/03/30)
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- Heterogeneous Catalytic Reductive Amination of Carbonyl Compounds with Ni-Al Alloy in Water as Solvent and Hydrogen Source
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The heterogeneous catalytic reductive amination of carbonyl compounds has been achieved by reactions of ammonium hydroxide and various amines with ketones and aldehydes. The process is based on the application of Raney type Ni-Al alloy in an aqueous medium. The reaction of the carbonyl compounds with the amine provided the corresponding Schiff bases that immediately underwent a reduction to provide primary and secondary amines as products. The controlled reaction of the Al content of the alloy with the solvent water generates hydrogen, and the in situ formed Raney Ni serves as a hydrogenation catalyst. The method is a simple and efficient way of preparing a broad variety of primary and secondary amines.
- Sch?fer, Christian,Ni?anci, Bilal,Bere, Matthew P.,Da?tan, Arif,T?r?k, Béla
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p. 3127 - 3133
(2016/09/09)
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- Preparation method of methylcyclohexanediamine
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The invention discloses a preparation method of methylcyclohexanediamine, wherein the preparation method comprises: dissolving methylphenylenediamine as a material in an organic solvent, and stirring and reacting at 150-200 DEG C under hydrogen pressure of 8-12 Mpa in the presence of a supporting metal catalyst and an inorganic salt aid for 5-10 hours to obtain the methylphenylenediamine. The preparation method provided herein solves the problems that existing preparation process of methylcyclohexanediamine is low in capacity and brings mass byproducts, and popularization of this product in more fields is reliably guaranteed.
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Paragraph 0026
(2017/04/03)
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- Asymmetric Amination of Secondary Alcohols by using a Redox-Neutral Two-Enzyme Cascade
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Multienzyme cascade approaches for the synthesis of optically pure molecules from simple achiral compounds are desired. Herein, a cofactor self-sufficient cascade protocol for the asymmetric amination of racemic secondary alcohols to the corresponding chiral amines was successfully constructed by employing an alcohol dehydrogenase and a newly developed amine dehydrogenase. The compatibility and the identical cofactor dependence of the two enzymes led to an ingenious in situ cofactor recycling system in the one-pot synthesis. The artificial redox-neutral cascade process allowed the transformation of racemic secondary alcohols into enantiopure amines with considerable conversions (up to 94 %) and >99 % enantiomeric excess at the expense of only ammonia; this method thus represents a concise and efficient route for the asymmetric synthesis of chiral amines. If you know what amine: A redox-neutral two-enzyme cascade encompassing an alcohol dehydrogenase (ADH) and an amine dehydrogenase (AmDH) is constructed for the synthesis of chiral amines from the corresponding racemic alcohols in one pot to afford considerable conversions (up to 94 %) and high enantiomeric excess values (>99 %) at the expense of only ammonia.
- Chen, Fei-Fei,Liu, You-Yan,Zheng, Gao-Wei,Xu, Jian-He
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p. 3838 - 3841
(2016/01/26)
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- Highly efficient one step synthesis of primary amines from B-Chlorodialkylboranes
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A convenient and simple method for synthesis of primary amines has been developed by direct amination of B-Chlorodialkylboranes. This general procedure has been applied to synthesize acyclic, cyclic, hindered and chiral amines in very high yields using both hydroxylamine-O-sulfonic acid and monochloroamine as reagents.
- Malhotra, Sanjay V.,Brown, Herbert C.
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experimental part
p. 383 - 385
(2012/08/28)
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- PYRROLO [1, 2-B] PYRIDAZINE DERIVATIVES AS JANUS KINASE INHIBITORS
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The invention provides compounds of formula l: ( I ) or a salt thereof as described herein. The invention also provides pharmaceutical compositions comprising a compound of formula I, processes for preparing compounds of formula I, intermediates useful for preparing compounds of formula I and therapeutic methods for suppressing an immune response or treating cancer or a hematologic malignancy using compounds of formula I.
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Page/Page column 89
(2011/02/24)
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- Structure-stability correlations for imine formation in aqueous solution
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Imine formation between 25 aldehydes and 13 amines in aqueous solution in the pH range 7-11 was studied by 1H NMR spectroscopy. A three-parameter linear equation correlating logarithms of imine formation constants with pKa and HOMO energies of amines and LUMO energies of aldehydes is proposed. In view of the widespread occurrence of imine-forming processes in both chemistry and biology, the data presented are of significance for physical organic chemistry and of particular interest for dynamic combinatorial chemistry. Copyright
- Godoy-Alcantar,Yatsimirsky, Anatoly K.,Lehn
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p. 979 - 985
(2007/10/03)
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- 2-aminopyridine derivatives and combinatorial libraries thereof
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The present invention relates to novel 2-aminopyridine derivative compounds of the following formula: wherein R1to R5have the meanings provided herein. The invention further relates to combinatorial libraries containing two or more such compounds, as well as methods of preparing 2-aminopyridine derivative compounds.
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- A kinetic investigation of the effects of fluorine and nickel on the HDN of toluidine on fully sulfided tungsten sulfide catalysts
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The effects of fluorine and nickel on the hydrodenitrogenation of o-toluidine on alumina-supported tungsten catalysts were studied in a continuous-flow reactor at 320 to 370°C and 3.0 MPa. The catalysts were prepared from ammonium tetrathiotungstate and were fully sulfided. The kinetic data were obtained by varying the initial partial pressure of the reactant and the reaction temperature; Langmuir-Hinshelwood models were used to fit the kinetic data. The simultaneous reactions of cyclohexene and o-toluidine enabled us to study the inhibition effect of o-toluidine on the hydrogenation of cyclohexene and to determine the difference between the sites for these reactions. The kinetic data suggest that the formation of toluene and 2-methylcyclohexylamine from o-toluidine occurs through a common partially hydrogenated intermediate, dihydrotoluidine, which leads to toluene by elimination and 2-methylcyclohexylamine after further hydrogenation. Fluorination changes neither the activation energies for the hydrogenation reaction nor the heat of adsorption of o-toluidine. Fluorine thus does not change the intrinsic properties of the active sites but does affect the apparent activity by influencing the number of active sites. Only a change in the morphology of the metal sulfide surface, by stacking, can explain the fluorine effect. Addition of nickel changes the nature of the active site by creating a nickel-associated sulfur vacancy, which is highly active for hydrogenation.
- Sun, Mingyong,Prins, Roel
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p. 192 - 200
(2007/10/03)
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- Stereoselective Reductions of Substituted Cyclohexyl and Cyclopentyl Carbon-Nitrogen ? Systems with Hydride Reagents
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Reductions of 3- and 4-substituted cyclohexyl imines, iminium salts, and enamines (via iminium ions) with various hydride reagents reveal that while small reagents (NaBH4, NaBH3CN) favor axial approach as observed with the corresponding ketones, even moderately bulky reagents (i.e., acetoxyboranes) attack preferentially from the equatorial side.This is in direct contrast to the results observed for the same reagents with the corresponding ketones and is interpreted as implying that additional steric interactions induced by the nitrogen substituents encumber axial attack by substituted hydride reagents and force approach from the equatorial direction.The very bulky tri-sec-butylborohydride anion affords highly stereodiscriminating equatorial attack.Reductions of 2-alkylcyclohexyl and 2-alkylcyclopentyl imines and enamines also proceed with high stereoselectivity to give cis-2-alkyl cyclic amines with both hindered and unhindered reagents.This is interpreted to be the result of (1) augmented steric interactions between nitrogen substituents and equatorial 2-alkyl groups (1,3-allylic strain) which induces conformational changes to favor the axial 2-alkyl conformer and (2) hindrance toward equatorial approach by reagents induced by axial alkyl substituents.The result is that equatorial approach is favored with equatorial 2-alkyl conformers and preferential axial approach with axial 2-alkyl conformers, leading to stereoselective production of cis-2-alkylamines. trans-2-n-Propyl-4-tert-butylcyclohexanone is reduced by LiBH(sec-Bu)3 preferentially from the axial direction in contrast to the usual highly selective equatorial attack observed with other cyclohexanones.
- Hutchins, Robert O.,Su, Wei-Yang,Sivakumar, Ramachandran,Cistone, Frank,Stercho, Yuriy P.
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p. 3412 - 3422
(2007/10/02)
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- A GENERAL, HIGHLY STEREOSELECTIVE SYNTHESIS OF AMINES
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The stereochemical course of cycloalkanone imine reductions by a variety of boron hydride reagents is described; very high stereoselectivity with substituted alkali metal borohydrides is reported.
- Wrobel, Jay E.,Ganem, Bruce
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p. 3447 - 3450
(2007/10/02)
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