5278-43-3Relevant academic research and scientific papers
Visible-Light-Mediated Oxidative Cyclization of 2-Aminobenzyl Alcohols and Secondary Alcohols Enabled by an Organic Photocatalyst
Xu, Jing-Xiu,Pan, Nan-Lian,Chen, Jia-Xi,Zhao, Jin-Wu
, p. 10747 - 10754 (2021/08/16)
This paper describes a visible-light-mediated oxidative cyclization of 2-aminobenzyl alcohols and secondary alcohols to produce quinolines at room temperature. This photocatalytic method employed anthraquinone as an organic small-molecule catalyst and DMSO as an oxidant. According to this present procedure, a series of quinolines were prepared in satisfactory yields.
Copper-catalyzed formal [3 + 3] annulations of arylketoximes and o-fluorobenzaldehydes: An entry to quinoline compounds
Xu, Zhenhua,Chen, Hongbiao,Deng, Guo-Jun,Huang, Huawen
supporting information, p. 936 - 942 (2021/02/01)
A copper-based catalytic system has been developed to enable efficient cyclization of ketoxime acetates with ofluorobenzaldehydes. This protocol offers an efficient method for the synthesis of substituted quinoline derivatives with a broad range of compatible functionalities. The present system also provides a rapid access to synthetically and pharmaceutically useful quinoline-fused polycycles such as benzo[c]acridines.
Modular Access to Spiro-dihydroquinolines via Scandium-Catalyzed Dearomative Annulation of Quinolines with Alkynes
Lou, Shao-Jie,Luo, Gen,Yamaguchi, Shigeru,An, Kun,Nishiura, Masayoshi,Hou, Zhaomin
supporting information, p. 20462 - 20471 (2021/12/03)
The catalytic enantioselective construction of three-dimensional molecular architectures from planar aromatics such as quinolines is of great interest and importance from the viewpoint of both organic synthesis and drug discovery, but there still exist many challenges. Here, we report the scandium-catalyzed asymmetric dearomative spiro-annulation of quinolines with alkynes. This protocol offers an efficient and selective route for the synthesis of spiro-dihydroquinoline derivatives containing a quaternary carbon stereocenter with an unprotected N-H group from readily accessible quinolines and diverse alkynes, featuring high yields, high enantioselectivity, 100% atom-efficiency, and broad substrate scope. Experimental and density functional theory studies revealed that the reaction proceeded through the C-H activation of the 2-aryl substituent in a quinoline substrate by a scandium alkyl (or amido) species followed by alkyne insertion into the Sc-aryl bond and the subsequent dearomative 1,2-addition of the resulting scandium alkenyl species to the C=N unit in the quinoline moiety. This work opens a new avenue for the dearomatization of quinolines, leading to efficient and selective construction of spiro molecular architectures that were previously difficult to access by other means.
Kinetic Resolution of 2,2-Disubstituted Dihydroquinolines through Chiral Phosphoric Acid-Catalyzed C6-Selective Asymmetric Halogenations
Chen, Yunrong,He, Yu-Peng,Liu, Wei,Tao, Houchao,Yang, Xiaoyu,Zhao, Fei,Zhu, Chaofan
supporting information, p. 4104 - 4108 (2021/06/27)
A novel kinetic resolution of 2,2-disubstituted dihydroquinolines was achieved by regioselective asymmetric halogenations enabled by chiral phosphoric acid catalysis. A series of dihydroquinolines bearing 2,2-disubstitutions were well-tolerated in these reactions, generating both the recovered dihydroquinolines and C-6-brominated products with high enantioselectivities, with s-factors up to 149. In addition, this kinetic resolution protocol is also applicable for 2,2-disubstituted tetrahydroquinoline and asymmetric iodonation reaction.
Mild and efficient copper-catalyzed oxidative cyclization of oximes with 2-aminobenzyl alcohols at room temperature: synthesis of polysubstituted quinolines
Liu, Yan-Yun,Wei, Yang,Huang, Zhi-Hui,Liu, Yilin
supporting information, p. 659 - 666 (2021/02/06)
A simple and efficient ligand-free Cu-catalyzed protocol for the synthesis of polysubstituted quinolinesviaoxidative cyclization of oxime acetates with 2-aminobenzyl alcohols at room temperature has been developed. The presented approach provides a new synthetic pathway leading to polysubstituted quinolines with good functional group tolerance under mild conditions. Moreover, this transformation can be applied for the preparation of quinolines on a gram scale. Oxime acetates serve as the internal oxidants in the reactions, thus making this method very attractive.
NiH-Catalyzed Hydroamination/Cyclization Cascade: Rapid Access to Quinolines
Chen, Qian,Gao, Yang,Hu, Xiao-Qiang,Huo, Yanping,Li, Xianwei,Yang, Simin
, p. 7772 - 7779 (2021/06/30)
Despite the significant success of metal-H-catalyzed hydroamination methodologies, considerable limitations still exist in the selective hydroamination of alkynes, especially for terminal alkynes. Herein, we develop a highly efficient NiH catalytic system that activates readily available alkynes for a cascade hydroamination/cyclization reaction with anthranils. This mild, operationally simple protocol is amenable to a wide array of alkynes including terminal and internal, aryl and alkyl, electron-deficient and electron-rich ones, delivering structurally diverse quinolines in useful to excellent yields (>80 examples, up to 93% yield). The utility of this procedure is exhibited in the late-stage functionalization of several natural products and in the concise synthesis of an antitumor molecule graveolinine and a triplex DNA intercalator. Preliminary mechanistic experiments suggest an alkenylnickel-mediated alkyne hydroamination and an intramolecular cyclization/aromatization of putative enamine intermediates.
Quinoline derivative as well as preparation method and application thereof
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Paragraph 0129-0136, (2021/07/17)
The invention belongs to the technical field of chemical drug synthesis, and particularly relates to a quinoline derivative as well as a preparation method and application thereof. In a reaction system, firstly, a metal catalyst, a ligand and a silicon hydrogen reagent interact to generate metal hydride, the metal hydride and an alkyne compound are subjected to addition, the metal hydride and an anthranil compound are subjected to an electrophilic amination reaction, and then the polysubstituted quinoline derivative is obtained through intramolecular cyclization. According to the invention, the starting raw materials such as the alkyne and the anthranil compound of the reaction are cheap and easily available, a variety of different polysubstituted quinoline derivatives can be constructed by using the one-step method, and can be rapidly converted into other compounds through the oxidation, the reduction, the coupling and other approaches of the target molecule so as to provide the good application prospect in the fields of drug development and material preparation; and the method is mild in condition, green, efficient, simple to operate and very suitable for large-scale industrial production.
Ruthenium(II) Complexes of Heteroditopic N-Heterocyclic Carbene Ligands: Efficient Catalysts for C-N Bond Formation via a Hydrogen-Borrowing Strategy under Solvent-Free Conditions
Donthireddy,Mathoor Illam, Praseetha,Rit, Arnab
supporting information, p. 1835 - 1847 (2020/01/31)
Both imidazol-2-ylidene (ImNHC) and 1,2,3-triazol-5-ylidene (tzNHC) have evolved to be elite groups of N-heterocyclic carbene (NHC) ligands for homogeneous catalysis. To develop efficient ruthenium(II)-based catalysts incorporating these ligands for C-N bond-forming reactions via hydrogen-borrowing methodology, we utilized chelating ligands integrated with ImNHC and mesoionic tzNHC donors connected via a CH2 spacer with a diverse triazole backbone. The synthesized ruthenium(II) complexes 3 are found to be highly efficient for C-N bond formation across a wide range of primary amine and alcohol substrates under solvent-free conditions, and among all of the complexes studied here, catalyst 3a with a mesityl substituent displayed maximum activity. To our delight, catalyst 3a is also effective for the selective mono-N-methylation of various anilines utilizing methanol as a coupling partner, known to be relatively more difficult than other alcohols. Furthermore, complex 3a also delivers various substituted quinolines successfully via the reaction of 2-aminobenzyl alcohol with several secondary alcohols. Importantly, catalyst 3a exhibited the highest activity among the reported ruthenium(II) complexes for both the N-benzylation of aniline [achieving a turnover number (TON) of 50000] and the realization of quinoline 8a by reacting 2-aminobenzyl alcohol with 2-phenylethanol (attaining a TON of 30000).
Enantioselective Synthesis of Tetrahydroquinolines via One-Pot Cascade Biomimetic Reduction?
Zhao, Zi-Biao,Li, Xiang,Chen, Mu-Wang,Wu, Bo,Zhou, Yong-Gui
, p. 1691 - 1695 (2020/11/03)
A novel and efficient protocol for the synthesis of chiral tetrahydroquinoline derivatives with excellent enantioselectivities and high yields has been developed through one-pot cascade biomimetic reduction. The detailed reaction pathway includes the acid-catalyzed and ruthenium-catalyzed formation of aromatic quinoline intermediates and biomimetic asymmetric reduction.
Fe2O3@[proline]–CuMgAl–LDH: A magnetic bifunctional copper and organocatalyst system for one-pot synthesis of quinolines and 2H-indazoles in green media
Esfandiary, Naghmeh,Heydari, Akbar
, (2020/05/25)
A novel magnetic core–shell Fe2O3@[proline]–CuMgAl–L(ayered)D(ouble)H(ydroxide) was designed as an efficient bifunctional catalytic system. To this end, Cu (II) was combined with Mg and Al in the LDH structure and l-proline was intercalated between LDH layers in order to perform a straightforward synthesis of quinolines and 2H-indazoles as two important pharmaceutical N-aryl-substituted heterocyclic compounds. In this regard, a facile method was employed through consecutive condensation under a mild conditions in choline azide media, which played the role of a reagent and a solvent to avoid toxic solvents and hazardous azidation reagents. These techniques provided considerable improvement in terms of using green media, reducing starting materials, reaching higher yields and offering a shorter reaction time and lower temperature. In conclusion, it was found that the catalyst could be reused five times with no significant loss of activity.
