1721-89-7Relevant articles and documents
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.
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Key,Bailey
, p. 763 (1938)
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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.
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.
