396-30-5Relevant academic research and scientific papers
High efficiency microwave-assisted synthesis of quinoline from acrolein diethyl acetal and aniline utilizing Ni/Beta catalyst
Li, An,Yang, Zan,Yang, Tao,Luo, Cai-Wu,Chao, Zi-Sheng,Zhou, Cong-Shan
, p. 21 - 25 (2018)
A facile and solvent-free microwave-assisted approach to quinoline was developed by utilizing both acrolein diethyl acetal and aniline as reagents, firstly employing Ni/Beta zeolite as mild, ecofriendly and low-cost solid catalyst. As high as 83% yield of quinoline was quickly achieved at a short microwave time. The results indicated that the effect of Ni on Beta zeolite not only significantly promoted conversion of acrolein diethyl acetal to effective intermediate but also dramatically accelerated dehydrogenation rate of tetrahydroquinoline/dihydroquinoline to quinoline.
Dehydrogenation of N-Heterocyclic Compounds Using H2O2 and Mediated by Polar Solvents
Llopis, Natalia,Gisbert, Patricia,Baeza, Alejandro,Correa-Campillo, Jara
supporting information, p. 1205 - 1210 (2022/02/25)
The oxidative dehydrogenation of N-heterocyclic compounds by using H2O2 as oxidant in combination with polar solvents such as 1,1,1,3,3,3-hexafluoroisopropanol (HFIP) and H2O is described. Among these two solvents, the best yields for the heteroaromatic compounds were generally achieved in HFIP. However, it is remarkable, that the use of a non toxic solvent such as H2O gave such good yields. Furthermore, the procedure was implemented in larger-scale and HFIP was distilled from the reaction mixture and reused (up to 5 cycles) without a significant detriment in the reaction outcome. (Figure presented.).
Method for realizing oxidative dehydrogenation of nitrogen-containing heterocyclic ring by using biomass-based carbon material
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Paragraph 0010-0011; 0026-0027, (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.
Monomeric vanadium oxide: A very efficient species for promoting aerobic oxidative dehydrogenation of N-heterocycles
Xie, Zhenbing,Chen, Bingfeng,Zheng, Lirong,Peng, Fangfang,Liu, Huizhen,Han, Buxing
, p. 431 - 437 (2021/01/11)
Monomeric active species are very interesting in heterogeneous catalysis. In this work, we proposed a method to prepare VOx-NbOy@C catalysts, which involve the one-pot hydrothermal synthesis of inorganic/organic hybrid materials containing V/Nb followed by thermal treatment under a reducing atmosphere. The prepared catalysts were characterized using different techniques, such as high-angle annular dark-field scanning transmission electron microscopy and X-ray absorption fine structure spectroscopy. It was shown that monomeric VOx species were dispersed homogeneously in the catalysts. The VOx-NbOy@C catalysts displayed high performance in the aerobic oxidative dehydrogenation of N-heterocycles to aromatic heterocycles. It was demonstrated that the selectivity of reaction over the catalyst with a very small amount of V (0.07 wt%) was much higher than that over the NbOy@C, and the catalyst also exhibited excellent stability in the reaction. The detailed study indicated that monomeric VO2 species were the most effective for promoting the reaction. This journal is
Geometric and electronic effects on the performance of a bifunctional Ru2P catalyst in the hydrogenation and acceptorless dehydrogenation of N-heteroarenes
Shao, Fangjun,Yao, Zihao,Gao, Yijing,Zhou, Qiang,Bao, Zhikang,Zhuang, Guilin,Zhong, Xing,Wu, Chuan,Wei, Zhongzhe,Wang, Jianguo
, p. 1185 - 1194 (2021/02/16)
The development of bifunctional catalysts for the efficient hydrogenation and acceptorless dehydrogenation of N-heterocycles is a challenge. In this study, Ru2P/AC effectively promoted reversible transformations between unsaturated and saturated N-heterocycles affording yields of 98% and 99%, respectively. Moreover, a remarkable enhancement in the reusability of Ru2P/AC was observed compared with other Ru-based catalysts. According to density functional theory calculations, the superior performance of Ru2P/AC was ascribed to specific synergistic factors, namely geometric and electronic effects induced by P. P greatly reduced the large Ru-Ru ensembles and finely modified the electronic structures, leading to a low reaction barrier and high desorption ability of the catalyst, further boosting the hydrogenation and acceptorless dehydrogenation processes.
Metal-Free Deoxygenation of Amine N-Oxides: Synthetic and Mechanistic Studies
Lecroq, William,Schleinitz, Jules,Billoue, Mallaury,Perfetto, Anna,Gaumont, Annie-Claude,Lalevée, Jacques,Ciofini, Ilaria,Grimaud, Laurence,Lakhdar, Sami
, p. 1237 - 1242 (2021/06/01)
We report herein an unprecedented combination of light and P(III)/P(V) redox cycling for the efficient deoxygenation of aromatic amine N-oxides. Moreover, we discovered that a large variety of aliphatic amine N-oxides can easily be deoxygenated by using only phenylsilane. These practically simple approaches proceed well under metal-free conditions, tolerate many functionalities and are highly chemoselective. Combined experimental and computational studies enabled a deep understanding of factors controlling the reactivity of both aromatic and aliphatic amine N-oxides.
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).
Highly chemoselective deoxygenation of N-heterocyclic: N -oxides under transition metal-free conditions
Kim, Se Hyun,An, Ju Hyeon,Lee, Jun Hee
supporting information, p. 3735 - 3742 (2021/05/04)
Because their site-selective C-H functionalizations are now considered one of the most useful tools for synthesizing various N-heterocyclic compounds, the highly chemoselective deoxygenation of densely functionalized N-heterocyclic N-oxides has received much attention from the synthetic chemistry community. Here, we provide a protocol for the highly chemoselective deoxygenation of various functionalized N-oxides under visible light-mediated photoredox conditions with Na2-eosin Y as an organophotocatalyst. Mechanistic studies imply that the excited state of the organophotocatalyst is reductively quenched by Hantzsch esters. This operationally simple technique tolerates a wide range of functional groups and allows high-yield, multigram-scale deoxygenation. This journal is
Superacid-promoted synthesis of quinoline derivatives
Klumpp, Douglas A.,Stentzel, Michael R.,Vuong, Hein
supporting information, (2020/01/24)
A series of vinylogous imines have been prepared from anilines and cinnamaldehydes. These substrates react in superacidic media to provide quinolines and related compounds. A mechanism for the conversion is proposed which involves the cyclization of dicationic superelectrophilic intermediates. Aromatization of the quinoline ring is thought to occur by superacid-promoted elimination of benzene.
NCP-Type Pincer Iridium Complexes Catalyzed Transfer-Dehydrogenation of Alkanes and Heterocycles?
Wang, Yulei,Qian, Lu,Huang, Zhidao,Liu, Guixia,Huang, Zheng
supporting information, p. 837 - 841 (2020/05/18)
A series of NCP-type pincer iridium complexes, (RNCCP)IrHCl (2a—2c) and (BQ-NCOP)IrHCl 3, have been studied for catalytic transfer alkane dehydrogenation. Complex 3 containing a rigid benzoquinoline backbone exhibits high activity and robustness in dehydrogenation of alkanes to form alkenes. Even more importantly, this catalyst system was also highly effective in the dehydrogenation of a wide range of heterocycles to furnish heteroarenes.
