613-50-3Relevant articles and documents
Method for realizing oxidative dehydrogenation of nitrogen-containing heterocyclic ring by using biomass-based carbon material
-
Paragraph 0010-0011; 0028-0029, (2021/06/26)
The invention provides a method for realizing oxidative dehydrogenation of a nitrogen-containing heterocyclic ring by using a biomass-based carbon material, and belongs to the field of organic synthesis. According to the method, the raw materials of the biomass-based carbon material comprise wheat, sorghum, rice, corn straw, wheat straw, peanut shells, sesame shells, bean shells and the like, and are crushed and then ground into powder, the powder is fully mixed with an inorganic alkali, and calcination is performed in an inert gas atmosphere to prepare the biomass-based carbon material; and by using air as an oxygen source, at a temperature of 50-120 DEG C, oxidative dehydrogenation of nitrogen-containing heterocyclic compounds to synthesize quinoline compounds, isoquinoline compounds, acridine compounds, quinazoline compounds, indole compounds, imine compounds, and even quinoline compounds with pharmaceutical activity can be achieved. According to the present invention, easily available wheat flour is adopted as a raw material to prepare a non-metal catalyst, the alkali is not added during the reaction process, and a remarkable industrial application prospect is achieved.
Photoinduced Iron-Catalyzed ipso-Nitration of Aryl Halides via Single-Electron Transfer
Wu, Cunluo,Bian, Qilong,Ding, Tao,Tang, Mingming,Zhang, Wenkai,Xu, Yuanqing,Liu, Baoying,Xu, Hao,Li, Hai-Bei,Fu, Hua
, p. 9561 - 9568 (2021/08/06)
A photoinduced iron-catalyzed ipso-nitration of aryl halides with KNO2 has been developed, in which aryl iodides, bromides, and some of aryl chlorides are feasible. The mechanism investigations show that the in situ formed iron complex by FeSO4, KNO2, and 1,10-phenanthroline acts as the light-harvesting photocatalyst with a longer lifetime of the excited state, and the reaction undergoes a photoinduced single-electron transfer (SET) process. This work represents an example for the photoinduced iron-catalyzed Ullmann-type couplings.
Highly Chemoselective Deoxygenation of N-Heterocyclic N-Oxides Using Hantzsch Esters as Mild Reducing Agents
An, Ju Hyeon,Kim, Kyu Dong,Lee, Jun Hee
supporting information, p. 2876 - 2894 (2021/02/01)
Herein, we disclose a highly chemoselective room-temperature deoxygenation method applicable to various functionalized N-heterocyclic N-oxides via visible light-mediated metallaphotoredox catalysis using Hantzsch esters as the sole stoichiometric reductant. Despite the feasibility of catalyst-free conditions, most of these deoxygenations can be completed within a few minutes using only a tiny amount of a catalyst. This technology also allows for multigram-scale reactions even with an extremely low catalyst loading of 0.01 mol %. The scope of this scalable and operationally convenient protocol encompasses a wide range of functional groups, such as amides, carbamates, esters, ketones, nitrile groups, nitro groups, and halogens, which provide access to the corresponding deoxygenated N-heterocycles in good to excellent yields (an average of an 86.8% yield for a total of 45 examples).
Visible-Light-Promoted Efficient Aerobic Dehydrogenation of N-Heterocycles by a Tiny Organic Semiconductor Under Ambient Conditions
Su, Chenliang,Yu, Kunyi,Zhang, Hanjie,Zhu, Yongfa
supporting information, p. 1956 - 1960 (2020/04/10)
An efficient reusable catalytic system has been developed based on perylene diimide (PDI) organic semiconductor for the aerobic dehydrogenation of N-heterocycles with visible light. This practical catalytic system without any additives proceeds under ambient conditions. The minute aggregates of PDI molecules on the surface of SiO2 nanospheres form tiny organic semiconductors, resulting in high-efficiency photo-oxidative activity. Notably, the robustness of this method is demonstrated by the synthesis of a wide range of N-heteroarenes, gram-scale experiments as well as reusability tests.
Metal–Organic Frameworks for the Exploitation of Distance between Active Sites in Efficient Photocatalysis
Deng, Hexiang,Gong, Xuan,Jiang, Zhuo,Lu, Lingxiang,Shu, Yufei,Wang, Chao,Xu, Xiaohui
supporting information, p. 5326 - 5331 (2020/02/18)
Discoveries of the accurate spatial arrangement of active sites in biological systems and cooperation between them for high catalytic efficiency are two major events in biology. However, precise tuning of these aspects is largely missing in the design of artificial catalysts. Here, a series of metal–organic frameworks (MOFs) were used, not only to overcome the limit of distance between active sites in bio-systems, but also to unveil the critical role of this distance for efficient catalysis. A linear correlation was established between photocatalytic activity and the reciprocal of inter active-site distance; a smaller distance led to higher activity. Vacancies created at selected crystallographic positions of MOFs promoted their photocatalytic efficiency. MOF-525-J33 with 15.6 ? inter active-site distance and 33 % vacancies exhibited unprecedented high turnover frequency of 29.5 h?1 in visible-light-driven acceptorless dehydrogenation of tetrahydroquinoline at room temperature.
Nitrogen-coordinated cobalt nanocrystals for oxidative dehydrogenation and hydrogenation of N-heterocycles
Wu, Yue,Chen, Zheng,Cheong, Weng-Chon,Zhang, Chao,Zheng, Lirong,Yan, Wensheng,Yu, Rong,Chen, Chen,Li, Yadong
, p. 5345 - 5352 (2019/05/29)
To endow non-noble metals with the high catalytic activity that is typically exhibited by noble metals is the central yet challenging aim for substituting noble metals. In this regard, by exploiting the coordination effect of nitrogen, we prepared cobalt nanocrystals stabilized by nitrogen-doped graphitized carbon (Co NCs/N-C). The obtained Co NC/N-C catalyst showed extraordinary performances toward both oxidative dehydrogenation of N-heterocycles and its reverse hydrogenation process under extremely mild conditions. A nearly quantitative conversion could be achieved for oxidative dehydrogenation even at room temperature (25 °C), for which the coordination effect of nitrogen is responsible: the interaction of Co-N induces a partial positive charge on the Co surface, thereby promoting the reaction. In contrast, cobalt nanocrystals supported by pristine carbon (Co NCs/C) proved to be inactive for oxidative dehydrogenation, owing to the lack of nitrogen. Moreover, in Co NCs/N-C, the N-doped graphitized carbon formed a protective layer for Co NCs, which preserved the active valence of Co species and prevented the catalyst from leaching. It was found that the catalyst still retained its excellent catalytic activity after five regeneration cycles; in comparison, its cobaltous oxide counterpart (CoOx/N-C) was barely active. As for the mechanism, electron paramagnetic resonance (EPR) analysis revealed the formation of superoxide anion radicals during the dehydrogenation process. Interestingly, the pressure of feed hydrogen had little effect on the hydrogenation process. Our Co NC/N-C catalyst is capable of activating molecular oxygen and hydrogen as effectively as noble metals; the coordination effect of nitrogen and the protection by the carbon layer in combination confer tremendous potential on the Co NCs/N-C for substituting noble-metal-based catalysts and soluble catalysts for homogeneous reactions.
Metal-Free Dehydrogenation of N-Heterocycles by Ternary h-BCN Nanosheets with Visible Light
Zheng, Meifang,Shi, Jiale,Yuan, Tao,Wang, Xinchen
supporting information, p. 5487 - 5491 (2018/04/02)
An efficient metal-free catalytic system has been developed based on hexagonal boron carbon nitride (h-BCN) nanosheets for the dehydrogenation of N-heterocycles with visible light; hydrogen gas is released in the process, and thus no proton acceptor is needed. This acceptorless dehydrogenation of hydroquinolines, hydroisoquinolines, and indolines to the corresponding aromatic N-heterocycles occurred in excellent yield under visible-light irradiation at ambient temperature. With h-BCN as the photocatalyst and water as the solvent, this environmentally benign protocol shows broad substitution tolerance and high efficiency.
Method for preparing quinoline derivative by catalyzing oxidative dehydrogenation of nitrogen-containing heterocyclic ring through carbon nitride material
-
Paragraph 0018; 0019, (2017/08/29)
The invention belongs to the field of chemical synthesis, and particularly relates to a method for preparing a quinoline derivative by catalyzing oxidative dehydrogenation of a nitrogen-containing heterocyclic ring through a carbon nitride material. The carbon nitride material is prepared by using a nitrogen-containing organic macrocyclic compound as a precursor and calcining in an inert atmosphere. During a reaction, oxygen or air is used as an oxidant, and in the presence or absence of a solvent, the reaction is performed at 50-120 DEG C and the carbon nitrogen material can convert the nitrogen-containing heterocyclic ring into the corresponding quinoline derivative. According to the invention, no metal is introduced into a reaction system, and the method is easy to amplify; after being recycled for at least 9 times, a catalyst still maintain good selectivity and activity; therefore, the method has a significant practical prospect during industrial production.
Synthesis and Characterization of Iron-Nitrogen-Doped Graphene/Core-Shell Catalysts: Efficient Oxidative Dehydrogenation of N-Heterocycles
Cui, Xinjiang,Li, Yuehui,Bachmann, Stephan,Scalone, Michelangelo,Surkus, Annette-Enrica,Junge, Kathrin,Topf, Christoph,Beller, Matthias
supporting information, p. 10652 - 10658 (2015/09/28)
An important goal for nanocatalysis is the development of flexible and efficient methods for preparing active and stable core-shell catalysts. In this respect, we present the synthesis and characterization of iron oxides surrounded by nitrogen-doped-graphene shells immobilized on carbon support (labeled FeOx@NGr-C). Active catalytic materials are obtained in a simple, scalable and two-step method via pyrolysis of iron acetate and phenanthroline and subsequent selective leaching. The optimized FeOx@NGr-C catalyst showed high activity in oxidative dehydrogenations of several N-heterocycles. The utility of this benign methodology is demonstrated by the synthesis of pharmaceutically relevant quinolines. In addition, mechanistic studies prove that the reaction progresses via superoxide radical anions (·O2-).
Quinoline and phenanthroline preparation starting from glycerol via improved microwave-assisted modified Skraup reaction
Saggadi, Hanen,Luart, Denis,Thiebault, Nicolas,Polaert, Isabelle,Estel, Lionel,Len
, p. 21456 - 21464 (2014/06/10)
An efficient "green" modified Skraup reaction in neat water was developed using inexpensive, abundant and environmentally-friendly glycerol under microwave irradiation conditions. Starting from aniline derivatives, various quinolines were obtained in 10-66% yields. The use of nitroaniline led to the corresponding phenanthrolines in 15-52% yields, respectively. This journal is the Partner Organisations 2014.
