- Switching Selectivity in Copper-Catalyzed Transfer Hydrogenation of Nitriles to Primary Amine-Boranes and Secondary Amines under Mild Conditions
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A simple and efficient copper-catalyzed selective transfer hydrogenation of nitriles to primary amine-boranes and secondary amines with an oxazaborolidine-BH3 complex is reported. The selectivity control was achieved under mild conditions by switching the solvent and the copper catalysts. More than 30 primary amine-boranes and 40 secondary amines were synthesized via this strategy in high selectivity and yields of up to 95%. The strategy was applied to the synthesis of 15N labeled in 89% yield.
- Song, Hao,Xiao, Yao,Zhang, Zhuohua,Xiong, Wanjin,Wang, Ren,Guo, Liangcheng,Zhou, Taigang
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p. 790 - 800
(2022/01/11)
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- Nickel Complexes Bearing N,N,O-Tridentate Salicylaldiminato Ligand: Efficient Catalysts for Imines Formation via Dehydrogenative Coupling of Primary Alcohols with Amines
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Treatment of salicylaldiminato ligand L1H-L2H (L1H = 2,4-di-tert-butyl-6-((quinolin-8-ylimino)methyl)phenol; L2H = 2,4-di-tert-butyl-6-(((2-(diethylamino)ethyl)imino)methyl)phenol) with Ni(OAc)2·4H2O in refluxing ethanol afforded nickel complexes [(L1)Ni(OAc)] (1) and [(L2)Ni(OAc)] (2), respectively. Reaction of L3H (L3H = (2,4-di-tert-butyl-6-(((2-(pyridin-2-yl)ethyl)imino)methyl)phenol)) with Ni(OAc)2·4H2O in the presence of excess triethylanmine gave the dual ligands coordinated nickel complex [(L2)2Ni] (3). Complexes 1-3 were well characterized by high-resolution mass spectrometry, infrared spectroscopy, elemental analysis, and X-ray diffraction analysis. All the three Ni(II) complexes exhibited efficient activity and good selectivity in the acceptorless dehydrogenative coupling of alcohols and amines to produce imines and diimines. The present protocol provides an atom-economical and sustainable route for the synthesis of various imine derivatives by employing an earth-abundant nickel salt and easily prepared salicylaldiminato ligands.
- Han, Zhangang,Hao, Zhiqiang,Lin, Jin,Lu, Guo-Liang,Zhang, Junhua,Zhang, Xiaoying
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p. 3843 - 3853
(2021/11/18)
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- Ultra-small cobalt nanoparticles from molecularly-defined Co-salen complexes for catalytic synthesis of amines
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We report the synthesis of in situ generated cobalt nanoparticles from molecularly defined complexes as efficient and selective catalysts for reductive amination reactions. In the presence of ammonia and hydrogen, cobalt-salen complexes such as cobalt(ii)-N,N′-bis(salicylidene)-1,2-phenylenediamine produce ultra-small (2-4 nm) cobalt-nanoparticles embedded in a carbon-nitrogen framework. The resulting materials constitute stable, reusable and magnetically separable catalysts, which enable the synthesis of linear and branched benzylic, heterocyclic and aliphatic primary amines from carbonyl compounds and ammonia. The isolated nanoparticles also represent excellent catalysts for the synthesis of primary, secondary as well as tertiary amines including biologically relevant N-methyl amines.
- Beller, Matthias,Chandrashekhar, Vishwas G.,Gawande, Manoj B.,Jagadeesh, Rajenahally V.,Kalevaru, Narayana V.,Kamer, Paul C. J.,Senthamarai, Thirusangumurugan,Zbo?il, Radek
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p. 2973 - 2981
(2020/03/27)
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- Design, synthesis and identification of N, N-dibenzylcinnamamide (DBC) derivatives as novel ligands for α-synuclein fibrils by SPR evaluation system
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PET imaging of α-synuclein (α-syn) deposition in the brain will be an effective tool for earlier diagnosis of Parkinson's disease (PD) due to α-syn aggregation is the widely accepted biomarker for PD. However, the necessary PET radiotracer for imaging is clinically unavailable until now. The lead compound discovery is the first key step for the study. Herein, we initially established an efficient biologically evaluation system well in high throughput based on SPR technology, and identified a novel class of N, N-dibenzylcinnamamide (DBC) compounds as α-syn ligands through the assay. These compounds were proved to have high affinities against α-syn aggregates (KD D) has been acquired, indicating its potential as a new lead compound for developing PET radiotracer.
- Chen, Yan-Fei,Bian, Jiang,Zhang, Peng,Bu, Lu-Lu,Shen, Yan,Yu, Wen-Bo,Lu, Xiu-Hong,Lin, Xin,Ye, De-Yong,Wang, Jian,Chu, Yong
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- Compound capable of being strongly bound with alpha-synuclein aggregate, and preparation method and use of compound
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The invention belongs to the technical field of medicine, and relates to a compound with a structural general formula I, and a preparation method and use of the compound. In the formula I, R1 is selected from phenyl, substituted phenyl, pyridyl and pyrimidinyl, and i is selected from 0 to 2, and is an integer; R2 is selected from alkyl, phenyl, substituted phenyl and 5-6-membered aromatic heterocyclic rings, and m is selected from 0 to 5, and is an integer; and R3 is selected from phenyl and substituted phenyl, and n is selected from 0 to 3, and is an integer. The compound comprises a cis-isomer, a trans-isomer or a mixture of the cis-isomer and the trans-isomer of the compound with the formula I structure. The compound can be strongly bound to an alpha-synuclein aggregate, can be used asan imaging tracer for the image technology such as PET, SPECT and the like, or can be used for preparing an imaging tracer and a composition containing the imaging tracer, the compound can be used forparticularly detecting Parkinson's disease or neurological disorders associated with the misfolding and aggregation of alpha-synuclein, and the compound has very good application prospects.
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Paragraph 0027; 0029-0031; 0099-0101
(2019/08/30)
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- Hydrogenation and Reductive Amination of Aldehydes using Triphos Ruthenium Catalysts
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An air-stable and readily accessible ruthenium dihydride complex catalyses aldehyde hydrogenation under neutral conditions. A high activity has been shown in a number of examples, and solvent-free conditions are also applicable, which favours industrial-scale applications. The catalyst has also been demonstrated to be active at low catalyst loadings for the reductive amination of aldehydes under mildly acidic conditions. A number of examples of chemoselectivity challenges are also presented in which the catalyst does not reduce carbon?halogen groups, alkene or ketone functionality. The advantage of using the pre-formed complex, Triphos-Ru(CO)H2 (1), over in situ formed catalysts from Triphos and Ru(acac)3 (acac=acetylacetonate) is also shown in terms of both chemoselectivity and activity, in particular this can be seen if low reaction temperatures are used.
- Christie, Francesca,Zanotti-Gerosa, Antonio,Grainger, Damian
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p. 1012 - 1018
(2018/01/27)
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- Preparation of the Ru3(CO)8-pyridine-alcohol cluster and its use for the selective catalytic transformation of primary to secondary amines
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The synthesis of pyridine alcohol based ruthenium carbonyl clusters Ru3(hep)2(CO)8 (1), Ru3(hpp)2(CO)8 (2), and Ru3(bhmp-H)2(CO)8 (3) {hep-H = 2-(2-hydroxyethyl)pyridine, hpp-H = 2-(3-hydroxypropyl)pyridine and bhmp-H2 = 2,6-bis(hydroxymethyl)pyridine} has been carried out by the reaction of the corresponding pyridine-alcohol ligands with Ru3(CO)12. Clusters 1-3 have been characterized using elemental analysis, NMR, FT-IR, mass spectrometry and single-crystal X-ray structures. The clusters were explored for the selective catalytic transformation of primary amines into secondary amines using alcohols as the mono-alkylating agents via hydrogen transfer reactions. All three display efficient catalytic activity with 1 being the most effective.
- Singh, Ajeet,Mobin, Shaikh M.,Mathur, Pradeep
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p. 14033 - 14040
(2018/11/23)
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- Expanding Water/Base Tolerant Frustrated Lewis Pair Chemistry to Alkylamines Enables Broad Scope Reductive Aminations
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Lower Lewis acidity boranes demonstrate greater tolerance to combinations of water/strong Br?nsted bases than B(C6F5)3, this enables Si?H bond activation by a frustrated Lewis pair (FLP) mechanism to proceed in the presence of H2O/alkylamines. Specifically, BPh3has improved water tolerance in the presence of alkylamines as the Br?nsted acidic adduct H2O–BPh3does not undergo irreversible deprotonation with aliphatic amines in contrast to H2O–B(C6F5)3. Therefore BPh3is a catalyst for the reductive amination of aldehydes and ketones with alkylamines using silanes as reductants. A range of amines inaccessible using B(C6F5)3as catalyst, were accessible by reductive amination catalysed by BPh3via an operationally simple methodology requiring no purification of BPh3or reagents/solvent. BPh3has a complementary reductive amination scope to B(C6F5)3with the former not an effective catalyst for the reductive amination of arylamines, while the latter is not an effective catalyst for the reductive amination of alkylamines. This disparity is due to the different pKavalues of the water–borane adducts and the greater susceptibility of BPh3species towards protodeboronation. An understanding of the deactivation processes occurring using B(C6F5)3and BPh3as reductive amination catalysts led to the identification of a third triarylborane, B(3,5-Cl2C6H3)3, that has a broader substrate scope being able to catalyse the reductive amination of both aryl and alkyl amines with carbonyls.
- Fasano, Valerio,Ingleson, Michael J.
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supporting information
p. 2217 - 2224
(2017/02/18)
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- Use of Quantitative Structure - Activity Relationship (QSAR) and ADMET prediction studies as screening methods for design of benzyl urea derivatives for anti-cancer activity
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2D and 3D quantitative structure-activity relationship studies have been carried out for establishing a correlation between the structural properties of benzyl urea derivatives and their anti-tumour activities. From this correlation, the new chemical entities were designed, and their activity and absorption, distribution, metabolism, excretion, and toxicity properties were also predicted. Finally, the most promising compounds from these screening were synthesized and biologically evaluated for their anti-cancer properties. Compound 1-(2, 4-dimethylphenyl)-3, 3-dimethyl-1-(2-nitrobenzyl) urea (7d) showed significant anti-proliferative activity (at 100 μg/mL) in human cancer cell lines-T-cell leukemia (Jurkat J6), myelogenous leukemia (K562), and breast cancer (MCF-7) compared to reference standard 5-flurouracil.
- Lokwani, Deepak,Bhandari, Shashikant,Pujari, Radha,Shastri, Padma,Shelke, Ganesh,Pawar, Vidya
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p. 319 - 331
(2012/02/14)
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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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- 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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