1721-89-7Relevant academic research and scientific papers
Synthesis of quinolines from aniline and propanol over modified USY zeolite: Catalytic performance and mechanism evaluated by: In situ Fourier transform infrared spectroscopy
Huang, Chen,Li, An,Li, Li-Jun,Chao, Zi-Sheng
, p. 24950 - 24962 (2017)
The reaction of aniline and propanol to quinolines was conducted in a fixed-bed flow-type reactor, using a series of modified USY zeolite catalysts. The structural, textural and acidic properties of the catalyst were characterized by XRD, N2-physisorption, 27Al MAS NMR, NH3-TPD and pyridine-FTIR, while the mechanism for the reaction of aniline and propanol was investigated by in situ FTIR. It was identified that the reaction of aniline and propanol generated predominantly quinolines, including 2-ethyl-3-methylquinoline and other alkyl quinoline, N-alkyl aniline and other byproducts. Among others, the ZnCl2/Ni-USY catalyst exhibited the best performance, providing a 96.4% conversion of aniline and a 78.3% total yield of quinolines with 81.2% total selectivity to quinolines and 60.1% selectivity to 2-ethyl-3-methylquinoline at 683 K. This was attributed to the larger concentration ratio of Lewis acid sites to Bronsted acid sites over the ZnCl2/Ni-USY catalyst, relative to other catalysts. There were predominantly two possible routes for the formation of quinolines, which required predominantly Lewis acid sites and Bronsted acid sites, respectively. In both the routes, N-phenylpropan-1-imine was proposed as the key intermediate. Relative to that based on Bronsted acid sites, the route based on Lewis acid sites appeared to contribute much more in the generation of quinolines from the reaction of aniline and propanol.
Heterogeneous catalytic synthesis of quinoline compounds from aniline and C1-C4 alcohols over zeolite-based catalysts
Huang, Chen,Li, An,Chao, Zi-Sheng
, p. 48275 - 48285 (2017)
The synthesis of quinolines from aniline and a C1-C4 alcohol was conducted under gas-phase reaction conditions over a series of zeolite-based catalysts. The texture and acid properties of catalysts were characterized by XRD, FT-IR, BET and NH3-TPD techniques. It was found that the total yield of quinolines was positively related to the relative content of Lewis acid sites of the catalyst. Among others, the ZnCl2/Ni-USY-acid catalyst possessed the best performance. Over this catalyst, the reactions of aniline and most of the alcohols provided a 42.3-79.7% total yield of quinolones under mild conditions, however, those of aniline and methanol, ethanol and iso-propanol predominantly led to N-alkylanilines. Furthermore, the reaction pathways for synthesizing quinolines via aniline reacting with polyhydric alcohols or monohydric alcohols was proposed in our work.
Oxygen-implanted MoS2 nanosheets promoting quinoline synthesis from nitroarenes and aliphatic alcohols via an integrated oxidation transfer hydrogenation-cyclization mechanism
Gao, Zhuyan,Huang, Zhipeng,Lu, Jianmin,Mu, Junju,Ren, Puning,Su, Kaiyi,Wang, Feng,Zhang, Chaofeng,Zhang, Shichao
, p. 1704 - 1713 (2022/03/08)
We herein report that MoS2 with oxygen-implanting modification (O-MoS2) can work as a multifunctional catalyst to achieve the one-pot quinoline synthesis from basic nitroarenes and aliphatic alcohols. Different from common knowledge that the application of MoS2-based catalysts and above quinoline synthesis need anaerobic conditions, we conduct the heterogeneous catalysis under an unusual air atmosphere. Catalyst characterization and experimental results indicate that the MoOx clusters implanted in the MoS2 skeleton, not the coordinatively unsaturated Mo sites (CUS Mo), dominate the generation of quinolines. By overturning the catalysis perception that O2 adsorption on MoSx can deactivate the MoS2-based catalysts using an efficient method for in situ healing of the MoOx structure in O-MoS2 and protecting the O-MoS2 catalyst by inhibiting unwanted MoOx elimination with extra H*, we innovatively introduce O2 into the quinoline synthesis. The robust O-MoS2 can be consecutively used ten times without regeneration and it offers 69-75% yields of 2-methylquinoline from nitrobenzene and ethanol. Furthermore, different from the traditional transfer hydrogenation-condensation mechanism, an integrated oxidation-transfer hydrogenation-cyclization mechanism is proposed over the O-MoS2 catalyst.
ZnMe2-Mediated, Direct Alkylation of Electron-Deficient N-Heteroarenes with 1,1-Diborylalkanes: Scope and Mechanism
Jo, Woohyun,Baek, Seung-Yeol,Hwang, Chiwon,Heo, Joon,Baik, Mu-Hyun,Cho, Seung Hwan
supporting information, p. 13235 - 13245 (2020/09/01)
The regioselective, direct alkylation of electron-deficient N-heteroarenes is, in principle, a powerful and efficient way of accessing alkylated N-heteroarenes that are important core structures of many biologically active compounds and pharmaceutical agents. Herein, we report a ZnMe2-promoted, direct C2- or C4-selective primary and secondary alkylation of pyridines and quinolines using 1,1-diborylalkanes as alkylation sources. While substituted pyridines and quinolines exclusively afford C2-alkylated products, simple pyridine delivers C4-alkylated pyridine with excellent regioselectivity. The reaction scope is remarkably broad, and a range of C2- or C4-alkylated electron-deficient N-heteroarenes are obtained in good yields. Experimental and computational mechanistic studies imply that ZnMe2 serves not only as an activator of 1,1-diborylalkanes to generate (α-borylalkyl)methylalkoxy zincate, which acts as a Lewis acid to bind to the nitrogen atom of the heterocycles and controls the regioselectivity, but also as an oxidant for rearomatizing the dihydro-N-heteroarene intermediates to release the product.
Rh-Catalyzed C-H Amination/Annulation of Acrylic Acids and Anthranils by Using -COOH as a Deciduous Directing Group: An Access to Diverse Quinolines
Gao, Yang,Nie, Jianhong,Li, Yibiao,Li, Xianwei,Chen, Qian,Huo, Yanping,Hu, Xiao-Qiang
supporting information, p. 2600 - 2605 (2020/04/02)
A method for the synthesis of diverse polysubstituted quinolines from readily available acrylic acids and anthranils has been developed. The weakly coordinating -COOH directing group, which can be tracelessly removed in the cascade cyclization, is essential for this reaction. Diverse polysubstituted quinolines were obtained under mild reaction conditions with simple H2O and CO2 as byproducts. More importantly, 1,2,3,4-tetrahydroacridine, which is the core skeleton of tacrine (an Alzheimer's disease drug), was conveniently synthesized.
Highly Diastereo- And Enantioselective Ir-Catalyzed Hydrogenation of 2,3-Disubstituted Quinolines with Structurally Fine-Tuned Phosphine-Phosphoramidite Ligands
Hu, Xin-Hu,Hu, Xiang-Ping
supporting information, p. 10003 - 10006 (2019/12/24)
A highly diastereo- and enantioselective Ir-catalyzed hydrogenation of unfunctionalized 2,3-disubstituted quinolines, especially 3-alkyl-2-arylquinolines, has been realized. The success of this hydrogenation is ascribed to the use of a structurally fine-tuned chiral phosphine-phosphoramidite ligand with a (Sa)-3,3′-dimethyl H8-naphthyl moiety and (Rc)-1-phenylethylamine backbone. The hydrogenation displayed broad functional group tolerance, thus furnishing a wide range of optically active 2,3-disubstituted tetrahydroquinolines in up to 96% ee and with perfect cis-diastereoselectivity.
Phosphine Ligand-Free Ruthenium Complexes as Efficient Catalysts for the Synthesis of Quinolines and Pyridines by Acceptorless Dehydrogenative Coupling Reactions
Guo, Bin,Yu, Tian-Qi,Li, Hong-Xi,Zhang, Shi-Qi,Braunstein, Pierre,Young, David J.,Li, Hai-Yan,Lang, Jian-Ping
, p. 2500 - 2510 (2019/05/10)
A series of phosphine-free Ru(III)/Ru(II) complexes of NH functionalized N?N?N pincer ligands exhibit excellent activity for acceptorless dehydrogenative coupling (ADC) of secondary alcohols with 2-aminobenzyl or γ-amino alcohols to quinolines and pyridines. Ru(III) complexes [LRuCl3] (L=6-(3-R1,5-R2-1H-pyrazol-1-yl)-N-(pyridin-2-yl)pyridin-2-amine; 1 a: R1=R2=H (L1); 1 b: R1=R2=Me (L2); 1 c: R1=H, R2=CF3 (L3); 1 d: R1=H, R2=Ph (L4); 1bMe: L=6-(3,5-dimethyl-1H-pyrazol-1-yl)-N-methyl-N-(pyridin-2-yl)pyridin-2-amine (L2Me)) were obtained by refluxing RuCl3 ? xH2O with the corresponding ligand in EtOH. Five Ru(II) complexes [LRu(DMSO-κS)Cl2] (2 a: L=L1; 2 b: L=L2; 2 c: L=L3; 2 d: L=L4; 2bMe: L=L2Me) were formed by reducing the corresponding Ru(III) complex in refluxing EtOH. The latter complexes could also be prepared directly by refluxing Ru(DMSO)4Cl2 with the corresponding ligand in EtOH. These Ru(III) and Ru(II) complexes, especially 1 b/2 b, exhibited high catalytic efficiency and broad functional group tolerance in ADC reactions of secondary alcohols with 2-aminobenzyl or γ-amino alcohols to quinolines and pyridines. A detail mechanistic study indicated the Ru(III) complex was reduced into the Ru(II) species, which is the active catalytic center for ADC via a Ru?H/N?H bifunctional outer-sphere mechanism. This protocol provides a reliable, atom-economical and environmentally benign procedure for C?N and C?C bond formation.
Method for catalyzing nitrogen heterocyclic ring compound for oxidative dehydrogenation with hydrotalcite-like material
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Paragraph 0048; 0049; 0050; 0051; 0053, (2017/10/27)
The invention relates to a method for catalyzing a nitrogen heterocyclic ring compound for oxidative dehydrogenation with a hydrotalcite-like material, and belongs to the application aspect of a hydrotalcite-like component. The hydrotalcite-like component can be expressed as: A-MxM-LDHs (A=OH or CO3; M=Ni, Co, Cu, Mg or Zn; M=Fe, Mn, Al; M/M=(2 to 4)). Under existence of the catalyst and without adding any additives, oxidative dehydrogenation reaction is performed on the heterocyclic ring compound under a mild condition to prepare a corresponding aromatic compound. According to the method provided by the invention, the hydrotalcite-like material is based on non-noble metal, can be synthesized largely, and can be recycled; the method has the advantages of being high in catalytic reaction efficiency, mild in reaction condition, low in cost, easy to industrialize and the like.
Blue-light-promoted carbon-carbon double bond isomerization and its application in the syntheses of quinolines
Chen, Xinzheng,Qiu, Shuxian,Wang, Sasa,Wang, Huifei,Zhai, Hongbin
supporting information, p. 6349 - 6352 (2017/08/10)
A blue-light-promoted carbon-carbon double bond isomerization in the absence of any photoredox catalyst is reported. It provides rapid access to a series of quinolines in good to excellent yields under simple aerobic conditions. The protocol is direct, catalyst-free and operationally convenient.
Copper-catalyzed retro-aldol reaction of β-hydroxy ketones or nitriles with aldehydes: Chemo- and stereoselective access to (E)-enones and (E)-acrylonitriles
Zhang, Song-Lin,Deng, Zhu-Qin
, p. 7282 - 7294 (2016/08/05)
A copper-catalyzed transfer aldol type reaction of β-hydroxy ketones or nitriles with aldehydes is reported, which enables chemo- and stereoselective access to (E)-α,β-unsaturated ketones and (E)-acrylonitriles. A key step of the in situ copper(i)-promoted retro-aldol reaction of β-hydroxy ketones or nitriles is proposed to generate a reactive Cu(i) enolate or cyanomethyl intermediate, which undergoes ensuing aldol condensation with aldehydes to deliver the products. This reaction uses 1.2 mol% Cu(IPr)Cl (IPr denotes 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene) as the catalyst in the presence of 6.0 mol% NaOtBu cocatalyst at room temperature or 70 °C. A range of aryl and heteroaryl aldehydes as well as acrylaldehydes are compatible with many useful functional groups being tolerated. Under the mild and weakly basic conditions, competitive Cannizzaro-type reaction of benzaldehydes and side reactions of base-sensitive functional groups can be effectively suppressed, which show synthetic advantages of this reaction compared to classic aldol reactions. The synthetic potential of this reaction is further demonstrated by the one-step synthesis of biologically active quinolines and 1,8-naphthyridine in excellent yields (up to 91%). Finally, a full catalytic cycle for this reaction has been constructed using DFT computational studies in the context of a retro-aldol/aldol two-stage mechanism. A rather flat reaction energy profile is found indicating that both stages are kinetically facile, which is consistent with the mild reaction conditions.
