- Tunable Synthesis of α-Amino Boronic Esters from Available Aldehydes and Amines through Sequential One-Pot Dehydration and Copper-Catalyzed Borylacylation
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Copper-catalyzed multicomponent borylacylation of imines with acid chlorides and bis(pinacolato)diboron was developed for the preparation of synthetically useful and pharmacologically relevant α-amino boronic acid derivatives. Starting from a range of acid chlorides and imines with aryl, heteroaryl, and alkyl substituents, most of these ligand-free reactions proceeded smoothly at room temperature in moderate to good yields. Furthermore, a facile and convenient one-pot, multistep access to the direct synthesis of α-amino boronic acid derivatives from available aldehydes and amines was also developed.
- Xia, Qi,Chang, Hua-Rong,Li, Juan,Wang, Jia-Yi,Peng, Yan-Qing,Song, Gong-Hua
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p. 2716 - 2724
(2020/01/31)
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- Synthesis of Secondary Aldimines from the Hydrogenative Cross-Coupling of Nitriles and Amines over Al2O3-Supported Ni Catalysts
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A heterogeneous Ni catalyst was discovered to be active in the synthesis of secondary cross-imines via hydrogenative coupling of nitriles and amines. The mesoporous Al2O3-supported Ni nanoparticles (abbreviated as Ni/m-Al2O3-600, where 600 represents the reduction temperature) were active in hydrogenative coupling of nitriles and amines reaction at 80 °C and 1 bar H2, affording corresponding cross-imines with yields in the range 64.1-98.1%. Density functional theory calculations reveal the hydrogenation of benzonitrile (PhCN) to benzylamine (PhCH2NH2) has higher activation energy than that for hydrogenative cross-coupling of PhCN and RNH2 on the Ni/m-Al2O3-600 catalyst, suggesting the latter reaction is more favorable. The theoretical calculations are in good agreement with our experimental results.
- Zhou, Peng,Jiang, Liang,Wang, Shuguo,Hu, Xun,Wang, Hongming,Yuan, Ziliang,Zhang, Zehui
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p. 8413 - 8423
(2019/09/07)
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- Integrative Theory/Experiment-Driven Exploration of a Multicomponent Reaction towards Imidazoline-2-(thi)ones
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Predicting reactivity in multicomponent reactions (MCRs) is extremely difficult. These reactions proceed by multiple pathways and are inherently associated with a potentially large variation of reactants and functional groups. To date, theoretical chemist
- Kruithof, Art,Mulder, Jos R.,Ruiz,Janssen, Elwin,Mooijman,Ruijter, Eelco,Fonseca Guerra, Célia,Bickelhaupt, F. Matthias,Orru, Romano V. A.
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supporting information
p. 104 - 112
(2018/01/17)
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- Mechanistic Studies on the Michael Addition of Amines and Hydrazines to Nitrostyrenes: Nitroalkane Elimination via a Retro-aza-Henry-Type Process
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In this article we report on the mechanistic studies of the Michael addition of amines and hydrazines to nitrostyrenes. Under the present conditions, the corresponding N-alkyl/aryl substituted benzyl imines and N-methyl/phenyl substituted benzyl hydrazones were observed via a retro-aza-Henry-type process. By combining organic synthesis and characterization experiments with computational chemistry calculations, we reveal that this reaction proceeds via a protic solvent-mediated mechanism. Experiments in deuterated methanol CD3OD reveal the synthesis and isolation of the corresponding deuterated intermediated Michael adduct, results that support the proposed slovent-mediated pathway. From the synthetic point of view, the reaction occurs under mild, noncatalytic conditions and can be used as a useful platform to yield the biologically important N-methyl pyrazoles in a one-pot manner, simple starting with the corresponding nitrostyrenes and the methylhydrazine.
- Kallitsakis, Michael G.,Tancini, Peter D.,Dixit, Mudit,Mpourmpakis, Giannis,Lykakis, Ioannis N.
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p. 1176 - 1184
(2018/02/09)
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- Direct synthesis of imines by 9-azabicyclo-[3,3,1]nonan-N-oxyl/KOH-catalyzed aerobic oxidative coupling of alcohols and amines
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A simple and efficient method for preparation of imines by the oxidative coupling of benzyl alcohols with aromatic amines or aliphatic amines was developed. The reaction was catalyzed by 9-azabicyclo[3.3.1]nonan-N-oxyl (ABNO)/KOH with air as the economic and green oxidant. Under the optimal reaction conditions, a variety of imines were obtained in 80%-96% isolated yields.
- Wan, Yan,Ma, Jia-Qi,Hong, Chao,Li, Mei-Chao,Jin, Li-Qun,Hu, Xin-Quan,Hu, Bao-Xiang,Mo, Wei-Min,Sun, Nan,Shen, Zhen-Lu
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p. 1269 - 1272
(2017/10/26)
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- The synthesis of α-aryl-α-aminophosphonates and α-aryl-α-aminophosphine oxides by the microwave-assisted Pudovik reaction
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A family of α-aryl-α-aminophosphonates and α-aryl-α-aminophosphine oxides was synthesized by the microwave-assisted solvent-free addition of dialkyl phosphites and diphenylphosphine oxide, respectively, to imines formed from benzaldehyde derivatives and primary amines. After optimization, the reactivity was mapped, and the fine mechanism was evaluated by DFT calculations. Two α-aminophosphonates were subjected to an X-ray study revealing a racemic dimer formation made through a N-H?O=P intermolecular hydrogen bridges pair.
- Bálint, Erika,Tajti, ádám,ádám, Anna,Csontos, István,Karaghiosoff, Konstantin,Czugler, Mátyás,ábrányi-Balogh, Péter,Keglevich, Gy?rgy
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supporting information
p. 76 - 86
(2017/02/15)
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- Method for preparing imine compound from alcohol and amine through catalytic oxidation
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The invention discloses a method for preparing an imine compound from alcohol and amine through catalytic oxidation. According to the method, an alcohol compound and an amine compound are used as reaction substrates, and a feeding mol ratio of the alcohol compound to the amine compound is 100: 100-60; 9-azabicyclo[3.3.1]nonane N-oxyl free radical is used as a catalyst, potassium hydroxide is used as an auxiliary agent, and a feeding mol ratio of the amine compound to the 9-azabicyclo[3.3.1]nonane N-oxyl free radical to potassium hydroxide is 100: 1-6: 10-50; air is used as an oxidizing agent, the reaction substrates are added into an organic solvent, and the mass of the used organic solvent is 2.5 to 5 times of the reaction substrate the amine compound; and a reaction is carried out at normal pressure at a temperature of 70 to 110 DEG C for 2 to 12 h, and aftertreatment is carried out after completion of the reaction so as to obtain the imine compound. The method provided by the invention is simple and safe to operate, reduces environmental cost due to usage of clean oxygen as the oxidizing agent and prevents the problem of transition-metal pollution by discarding usage of any transition-metal catalyst.
- -
-
Paragraph 0056
(2017/08/31)
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- Deep eutectic solvent catalyzed eco-friendly synthesis of imines and hydrobenzamides
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The urea-choline chloride-based deep eutectic solvent was found to be an efficient catalyst and reaction media for the additive-free synthesis of imines (Schiff bases) and hydrobenzamides by the reaction of aldehydes with amines and ammonia in good to high yields. Outstanding features of this protocol were the general and atom-economical reaction, absence of external catalysts and additives, simple workup, and availability and recycling of urea-choline chloride as a green solvent. Graphical abstract: (Chemical Equation Presented).
- Azizi, Najmedin,Edrisi, Mahtab
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p. 1695 - 1698
(2015/09/21)
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- Copper N-Heterocyclic Carbene: A Catalyst for Aerobic Oxidation or Reduction Reactions
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Copper N-heterocyclic carbene complexes can be readily used as catalysts for both aerobic oxidation of alcohols to aldehydes and reduction of imines to amines. Our methodology is universal for aromatic substrates and shows versatile tolerance to potential cascade reactions. A one-pot tandem synthetic strategy could afford useful imines and secondary amines via an oxidation-reduction strategy.
- Zhan, Le-Wu,Han, Lei,Xing, Ping,Jiang, Biao
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supporting information
p. 5990 - 5993
(2016/01/09)
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- AZOLE HETEROCYCLIC COMPOUND, PREPARATION METHOD, PHARMACEUTICAL COMPOSITION AND USE
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The present invention relates to the field of pharmaceutical chemistry, and in particular, to a novel class of azole compounds represented by general formula (I), (II) or (III) and a preparation method thereof, a pharmaceutical composition with the compounds as active components, and a use of the azole compounds and the pharmaceutical composition in the preparation of a medicament for treatment of diseases associated with Lp-PLA2 enzyme activities, wherein each substituent is as defined in the specification.
- -
-
Paragraph 0577
(2014/06/25)
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- Bio-inspired catalytic imine reduction by rhodium complexes with tethered hantzsch pyridinium groups: Evidence for direct hydride transfer from dihydropyridine to metal-activated substrate
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Inspired by Nature: A conceptually new design for a catalyst, combining a metal center abutted to an organic hydride donor, is demonstrated for the formate-driven transfer hydrogenation of imines under ambient conditions. A key step, transfer of hydride from the organohydride donor to the metal-polarized substrate, mirrors that in metallo-(de)hydrogenase enzymes.
- McSkimming, Alex,Bhadbhade, Mohan M.,Colbran, Stephen B.
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supporting information
p. 3411 - 3416
(2013/05/08)
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- Chemical reactivity and skin sensitization potential for benzaldehydes: Can Schiff base formation explain everything?
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Skin sensitizers chemically modify skin proteins rendering them immunogenic. Sensitizing chemicals have been divided into applicability domains according to their suspected reaction mechanism. The widely accepted Schiff base applicability domain covers aldehydes and ketones, and detailed structure-activity-modeling for this chemical group was presented. While Schiff base formation is the obvious reaction pathway for these chemicals, the in silico work was followed up by limited experimental work. It remains unclear whether hydrolytically labile Schiff bases can form sufficiently stable epitopes to trigger an immune response in the living organism with an excess of water being present. Here, we performed experimental studies on benzaldehydes of highly differing skin sensitization potential. Schiff base formation toward butylamine was evaluated in acetonitrile, and a detailed SAR study is presented. o-Hydroxybenzaldehydes such as salicylaldehyde and the oakmoss allergens atranol and chloratranol have a high propensity to form Schiff bases. The reactivity is highly reduced in p-hydroxy benzaldehydes such as the nonsensitizing vanillin with an intermediate reactivity for p-alkyl and p-methoxy-benzaldehydes. The work was followed up under more physiological conditions in the peptide reactivity assay with a lysine-containing heptapeptide. Under these conditions, Schiff base formation was only observable for the strong sensitizers atranol and chloratranol and for salicylaldehyde. Trapping experiments with NaBH3CN showed that Schiff base formation occurred under these conditions also for some less sensitizing aldehydes, but the reaction is not favored in the absence of in situ reduction. Surprisingly, the Schiff bases of some weaker sensitizers apparently may react further to form stable peptide adducts. These were identified as the amides between the lysine residues and the corresponding acids. Adduct formation was paralleled by oxidative deamination of the parent peptide at the lysine residue to form the peptide aldehyde. Our results explain the high sensitization potential of the oakmoss allergens by stable Schiff base formation and at the same time indicate a novel pathway for stable peptide-adduct formation and peptide modifications by aldehydes. The results thus may lead to a better understanding of the Schiff base applicability domain.
- Natsch, Andreas,Gfeller, Hans,Haupt, Tina,Brunner, Gerhard
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p. 2203 - 2215
(2013/01/15)
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- KOH-mediated transition metal-free synthesis of imines from alcohols and amines
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The various imines were prepared from alcohols and amines in moderate to good yields under an air atmosphere promoted by KOH, eliminating the need for toxic transition metal catalysts. Due to its simplicity, this protocol will have wide application in synthesis.
- Xu, Jian,Zhuang, Rongqiang,Bao, Lingling,Tang, Guo,Zhao, Yufen
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p. 2384 - 2387
(2013/02/21)
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- Direct and mild palladium-catalyzed aerobic oxidative synthesis of imines from alcohols and amines under ambient conditions
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By ligand, TEMPO, and base screening, we developed a mild and green one-pot imine synthesis from alcohols and amines via a low-loading palladium-catalyzed tandem aerobic alcohol oxidation-dehydrative condensation reaction that can be readily carried out in open air at room temperature.
- Jiang, Lan,Jin, Luolu,Tian, Haiwen,Yuan, Xueqin,Yu, Xiaochun,Xu, Qing
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supporting information; experimental part
p. 10833 - 10835
(2011/11/04)
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- A new protocol for a one-pot synthesis of α-amino phosphonates by reaction of imines prepared in situ with trialkylphosphites
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Imines prepared in situ by reaction of aldehydes and ketones with primary amines in ethereal solution of LiClO4 react readily at ambient temperature with trialkylphosphite to give high yields of α-amino phosphonates.
- Saidi, Mohammad R.,Azizi, Najmedin
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p. 1347 - 1349
(2007/10/03)
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- Ammonium chloride-promoted four-component synthesis of pyrrolo[3,4-b] pyridin-5-one
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A novel multicomponent synthesis of 5-aminooxazole starting from simple and readily available inputs is described. Thus, simply heating a methanol solution of an aldehyde 3, an amine 4, and an α-isocyanoacetamide 5 provided the 5-aminooxazole (1) in good
- Janvier, Pierre,Sun, Xiaowen,Bienayme, Hugues,Zhu, Jieping
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p. 2560 - 2567
(2007/10/03)
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- A simple one-pot three-component reaction for preparation of secondary amines and amino esters mediated by lithium perchlorate
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The one-pot synthesis of several secondary amines and secondary amino esters are reported. Treatment of aldehydes (aliphatic or aromatic) with (trimethylsilyl)alkylamines, in the presence of 5 M lithium perchlorate in diethyl ether gives intermediate imines. Reaction of these intermediate imines with different nucleophiles and functionalized organozinc reagents, BrZnCH2COOR, produce a variety of secondary amines and N-alkyl- or N-arylamino esters in good yields.
- Saidi, Mohammad R,Azizi, Najmoddin,Zali-Boinee, Hasan
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p. 6829 - 6832
(2007/10/03)
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- Benzylamines: Synthesis and evaluation of antimycobacterial properties
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The synthesis of benzylamines with various N-alkyl chains and substituents in the aromatic system as well as their evaluation on Mycobacterium tuberculosis H 37 Ra are described. The most active compounds in this test, N-methyl-3-chlorobenzylamine (MIC 10.2 μg/mL), N-methyl-3,5-dichlorobenzylamine (93, MIC 10.2 μg/mL), and N-butyl-3,5-difluorobenzylamine (MIC 6.4 μg/mL), also exhibited a marked inhibitory effect on Mycobacterium marinum and Mycobacterium lufu used for the determination of antileprotic properties. The combination of 93 with aminosalicylic acid, streptomycin, or dapsone exert marked supra-additive effects on M. tuberculosis H 37 Ra.
- Meindl,Von Angerer,Schonenberger,Ruckdeschel
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p. 1111 - 1118
(2007/10/02)
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