24698-70-2Relevant academic research and scientific papers
Method for synthesizing quinoline derivatives by copper catalysis
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Paragraph 0038-0043, (2021/03/24)
The invention relates to a method for synthesizing quinoline derivatives by copper catalysis. The method comprises the following steps: mixing 2-aminobenzyl alcohol, acetophenone derivatives, an alkaline reagent, a copper catalyst and a nitrogen-containing ligand in an organic solvent, and reacting at room temperature for 6-12h; and after the reaction is finished, sequentially carrying out concentration and column chromatography separation on the obtained reaction solution to obtain the corresponding quinoline derivative. Compared with the prior art, the method has the advantages that 2-aminobenzyl alcohol and acetophenone derivatives which are cheap and easy to obtain are used as raw materials, cuprous iodide CuI or cuprous bromide CuBr with stable properties is used as a catalyst, the quinoline skeleton-containing derivatives are directly constructed, use of toxic reagents is avoided, and the method conforms to the development concept of green chemistry; and the method has the advantages of simple operation, mild reaction conditions, good substrate universality and the like, and has huge application potential in the aspect of drug intermediate synthesis.
Zinc Stabilized Azo-anion Radical in Dehydrogenative Synthesis of N-Heterocycles. An Exclusively Ligand Centered Redox Controlled Approach
Das, Siuli,Mondal, Rakesh,Chakraborty, Gargi,Guin, Amit Kumar,Das, Abhishek,Paul, Nanda D.
, p. 7498 - 7512 (2021/06/30)
Herein we report an exclusively ligand-centered redox controlled approach for the dehydrogenation of a variety of N-heterocycles using a Zn(II)-stabilized azo-anion radical complex as the catalyst. A simple, easy-to-prepare, and bench-stable Zn(II)-complex (1b) featuring the tridentate arylazo pincer, 2-((4-chlorophenyl)diazenyl)-1,10-phenanthroline, in the presence of zinc-dust, undergoes reduction to form the azo-anion radical species [1b]- which efficiently dehydrogenates various saturated N-heterocycles such as 1,2,3,4-tetrahydro-2-methylquinoline, 1,2,3,4-tetrahydro-isoquinoline, indoline, 2-phenyl-2,3-dihydro-1H-benzoimidazole, 2,3-dihydro-2-phenylquinazolin-4(1H)-one, and 1,2,3,4-tetrahydro-2-phenylquinazolines, among others, under air. The catalyst has further been found to be compatible with the cascade synthesis of these N-heterocycles via dehydrogenative coupling of alcohols with other suitable coupling partners under air. Mechanistic investigation reveals that the dehydrogenation reactions proceed via a one-electron hydrogen atom transfer (HAT) pathway where the zinc-stabilized azo-anion radical ligand abstracts the hydrogen atom from the organic substrate(s), and the whole catalytic cycle proceeds via the exclusive involvement of the ligand-centered redox events where the zinc acts only as the template.
Ruthenium complex and preparation method thereof and catalytic application
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Paragraph 0104-0106; 0113-0114, (2021/01/24)
The invention discloses a ruthenium complex and a preparation method thereof and catalytic application. The ruthenium complex is reported for the first time. Research finds that the ruthenium complexhas the activity of catalytically synthesizing quinazoline and derivatives thereof or catalytically synthesizing quinoline and derivatives thereof. When the ruthenium complex provided by the inventionis used for catalytic synthesis of quinazoline and derivatives thereof or quinoline and derivatives thereof, the ruthenium complex has the advantages of mild reaction conditions, wide substrate range, high catalytic product yield and good functional group tolerance, and is significantly superior to the prior art.
Designed pincer ligand supported Co(ii)-based catalysts for dehydrogenative activation of alcohols: Studies onN-alkylation of amines, α-alkylation of ketones and synthesis of quinolines
Singh, Anshu,Maji, Ankur,Joshi, Mayank,Choudhury, Angshuman R.,Ghosh, Kaushik
, p. 8567 - 8587 (2021/06/30)
Base-metal catalystsCo1,Co2andCo3were synthesized from designed pincer ligandsL1,L2andL3having NNN donor atoms respectively.Co1,Co2andCo3were characterized by IR, UV-Vis. and ESI-MS spectroscopic studies. Single crystal X-ray diffraction studies were investigated to authenticate the molecular structures ofCo1andCo3. CatalystsCo1,Co2andCo3were utilized to study the dehydrogenative activation of alcohols forN-alkylation of amines, α-alkylation of ketones and synthesis of quinolines. Under optimized reaction conditions, a broad range of substrates including alcohols, anilines and ketones were exploited. A series of control experiments forN-alkylation of amines, α-alkylation of ketones and synthesis of quinolines were examined to understand the reaction pathway. ESI-MS spectral studies were investigated to characterize cobalt-alkoxide and cobalt-hydride intermediates. Reduction of styrene by evolved hydrogen gas during the reaction was investigated to authenticate the dehydrogenative nature of the catalysts. Probable reaction pathways were proposed forN-alkylation of amines, α-alkylation of ketones and synthesis of quinolines on the basis of control experiments and detection of reaction intermediates.
Porous FeO(OH) Dispersed on Mg-Al Hydrotalcite Surface for One-Pot Synthesis of Quinoline Derivatives
Motokura, Ken,Ozawa, Nao,Sato, Risako,Manaka, Yuichi,Chun, Wang-Jae
, p. 2915 - 2921 (2021/05/27)
The use of ubiquities elements such as iron instead of expensive precious metals as catalysts is one goal toward realizing environmentally benign synthetic chemistry. Here, we report that porous FeO(OH) dispersed on Mg?Al hydrotalcite acts as a bifunctional heterogeneous catalyst in the one-pot synthesis of 2-substituted quinoline derivatives through dehydrogenative oxidation-cyclization reactions. The catalyst was prepared by a simple grafting method using FeCl3 and Mg?Al hydrotalcite. The prepared porous FeO(OH) possesses a higher surface area than those previously reported for α-FeO(OH) particles. The one-pot quinoline synthesis proceeded effectively under non-noble-metal catalysis in air without requiring additional homogeneous bases or solvents.
Ruthenium-catalyzed acceptorless dehydrogenative coupling of o-aminobenzyl alcohols with ketones to quinolines in the presence of carbonate salt
Xu, Xiangchao,Ai, Yao,Wang, Rongzhou,Liu, Liping,Yang, Jiazhi,Li, Feng
, p. 340 - 349 (2021/02/27)
A ruthenium complex bearing a functional 2,2′-bibenzimidazole ligand [(p-cymene)Ru(BiBzImH2)Cl][Cl] was designed, synthesized and found to be a general and highly efficient catalyst for the synthesis of quinolines via acceptorless dehydrogenative coupling of o-aminobenzyl alcohols with ketones in the presence of carbonate salt. It was confirmed that NH units in the ligand are crucial for catalytic activity. The application of this catalytic system for the scale-gram synthesis of biologically active molecular was also undertaken. Notably, this research exhibits new potential of metal–ligand bifuctional catalysts for acceptorless dehydrogenative reactions.
A cobalt-catalyzed method for synthesizing quinoline and quinazoline compounds
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Paragraph 0011; 0038, (2022/01/10)
The present invention discloses a cobalt-catalyzed synthesis of quinoline and quinazoline compounds, by a benzene compound with amino and hydroxyl groups or benzonitrile compounds as raw materials, in the presence of a catalyst and a base by a receptor-fr
[(PPh3)2NiCl2]-Catalyzed C-N bond formation reaction via borrowing hydrogen strategy: Access to diverse secondary amines and quinolines
Donthireddy,Pandey, Vipin K.,Rit, Arnab
, p. 6994 - 7001 (2021/06/09)
Commercially available [(PPh3)2NiCl2] was found to be an efficient catalyst for the mono-N-alkylation of (hetero)- A romatic amines, employing alcohols to deliver diverse secondary amines, including the drug intermediates chloropyramine (5b) and mepyramine (5c), in excellent yields (up to 97%) via the borrowing hydrogen strategy. This method shows a superior activity (TON up to 10000) with a broad substrate scope at a low catalyst loading of 1 mol % and a short reaction time. Further, this strategy is also successful in accessing various quinoline derivatives following the acceptorless dehydrogenation pathway.
The preparation of a Co@C3N4catalyst and applications in the synthesis of quinolines from 2-aminobenzyl alcohols with ketones
Cao, Fei,Mao, Anruo,Yang, Bobin,Ge, Chenyang,Wang, Dawei
supporting information, p. 6768 - 6772 (2021/04/22)
An unsymmetrical diphenylphosphino-pyridinyl-triazole ligand was synthesized and characterized through IR, NMR and MS and the corresponding earth-abundant metal complex (cobalt) was prepared. Considering energy consumption and environmental friendliness, it is necessary to turn this diphenylphosphino-pyridinyl-triazole cobalt complex into a recyclable catalyst, which could easily be reused. Therefore, a heterogeneous catalyst was synthesized through Co-doping of C3N4, and the Co-nanoparticles on C3N4revealed high catalytic activity for the synthesis of quinolines with good recovery performance.
Efficient access to quinolines and quinazolines by ruthenium complexes catalyzed acceptorless dehydrogenative coupling of 2-aminoarylmethanols with ketones and nitriles
Feng, Qi,Han, Zhangang,Hao, Zhiqiang,Huo, Shuaicong,Kong, Siqi,Lin, Jin,Lu, Guo-Liang,Zeng, Guang
, (2021/09/08)
Treatment of N,N,O-tridentate pyrazolyl-pyridinyl-alcohol ligands, 2-(CR1R2OH)-6-[3,5-(R3)2C3HN2]C5H3N (R1 = R2 = Me, R3 = H (L1H); R1 = Me, R2 = Ph, R3 = H (L2H); R1 = R2 = Ph, R3 = H (L3H); R1 = R2 = R3 = Me (L4H)) with RuCl3?xH2O in refluxing EtOH afforded the corresponding Ru(III) complexes L2RuCl (1a-1d), which were well characterized by IR, HR-MS and X-ray single crystal structural determination. These Ru complexes showed similarly high catalytic performance for both dehydrogenative couplings of 2-aminoarylmethanols with ketones and nitriles, giving the quinolines and quinazolines in good to excellent yields. This protocol provides an atom-economical and sustainable route to access various structurally important quinoline and quinazoline derivatives by using phosphine-free ligand based Ru catalysts.
