2739-16-4Relevant articles and documents
N-methylation of quinolines with CO2 and H2 catalyzed by Ru-triphos complexes
He, Zhenhong,Liu, Huizhen,Qian, Qingli,Lu, Lu,Guo, Weiwei,Zhang, Lujun,Han, Buxing
, p. 927 - 933 (2017)
N-methyl-tetrahydroquinolines (MTHQs) are a kind of very useful chemicals, which can be obtained from N-methylation of amines. However, the methylation of quinolines which is a kind of highly unsaturated nitrogen-containing heterocyclic aromatic compounds has not been reported. In this work, we report the first work for the synthesis of MTHQs by methylation of quinolines using CO2 and H2. It was found that Ru(acac)3-triphos [triphos: 1,1,1-tris(diphenylphosphinomethyl)ethanl] complex was very active and selective for the N-methylation reaction of quinolines, and the yield of the desired product could reach 99%.
Ru-decorated N-doped carbon nanoflakes for selective hydrogenation of levulinic acid to γ-valerolactone and quinoline to tetrahydroquinoline with HCOOH in water
Chauhan, Arzoo,Kar, Ashish Kumar,Srivastava, Rajendra
, (2022/03/27)
The effective dissociation of biomass-derived formic acid, as a sustainable hydrogen source, in water is explored for the hydrogenation of levulinic acid (LA) and quinoline. Ru decorated carbon nanoflakes prepared by carboreduction (in Ar/H2 atmosphere) of Ru containing N-doped carbon were used as catalysts. The successful formation of Ru-decorated N-doped carbons was confirmed by numerous spectroscopic tools. The catalyst exhibited outstanding activity and selectivity for the hydrogenation of LA and quinoline using formic acid as a hydrogen donor in water under mild conditions. The catalyst afforded 99.8% LA conversion and 100% selectivity for γ-valerolactone (GVL), whereas 99.8% quinoline conversion and 93% selectivity for 1,2,3,4-tetrahydroquinoline (THQ) were obtained. Recycling experiments suggested that the catalyst was stable even after the 5 cycles. Various controlled experiments and characterizations were conducted to demonstrate the structure-activity relations and suggest plausible reaction mechanisms for the hydrogenation of LA and quinoline. The exploration of formic acid as a sustainable H2 source and the development of metal decorated N-doped carbons for hydrogenation of LA and quinoline will be fascinating to catalysis researchers and industrialists.
Quasi-continuous synthesis of cobalt single atom catalysts for transfer hydrogenation of quinoline
Cheng, Yujie,Gan, Tao,He, Qian,He, Xiaohui,Huang, Liyun,Ji, Hongbing,Sun, Qingdi,Zhang, Hao
, (2021/12/02)
Improving the transfer hydrogenation of N-heteroarenes is of key importance for various industrial processes and remains a challenge so far. We reported here a microcapsule-pyrolysis strategy to quasi-continuous synthesis S, N co-doped carbon supported Co single atom catalysts (Co/SNC), which was used for transfer hydrogenation of quinoline with formic acid as the hydrogen donor. Given the unique geometric and electronic properties of the Co single atoms, the excellent catalytic activity, selectivity and stability were observed. Benefiting from the quasi-continuous synthesis method, the as-obtained catalysts provide a reference for the large-scale preparation of single atom catalysts without amplification effect. Highly catalytic performances and quasi-continuous preparation process, demonstrating a new and promising approach to rational design of atomically dispersed catalysts with maximum atomic efficiency in industrial.
Catalytically Active Co?Nx Species Stabilized on Nitrogen-doped Porous Carbon for Efficient Hydrogenation and Dehydrogenation of N-heteroarenes
Xu, Dan,Zhao, Hong,Dong, Zhengping,Ma, Jiantai
, p. 4406 - 4415 (2020/07/06)
The development of bifunctional, highly active and stable non-noble-metal catalysts is important for synthetic chemistry. In this study, a highly dispersed Co catalyst stabilized on the mesoporous N-doped carbon layers was prepared by adsorption and pyrolysis of cobalt complex on dendritic fibrous silica nanospheres (KCC-1@Co?N?C?T). The characterizations of HAADF-STEM, XRD and XPS together with the KSCN poisoning tests determine the absence of Co0 or CoOx nanoparticles and suggest that the Co?Nx species are the active sites. The formation of Co?Nx species results from the properties of N-rich cobalt-phenanthroline complex and dendritic fibrous silica supports, increasing the original spatial distance between Co atoms and thus preventing them from aggregation. The KCC-1@Co?N?C-800 catalyst showed excellent activity and selectivity for the oxidative dehydrogenation (ODH) of saturated N-heterocycles and base-free catalytic transfer hydrogenation (CTH) of unsaturated N-heterocycles.
Biomass-derived N-doped porous carbon: An efficient metal-free catalyst for methylation of amines with CO2
Tang, Feiying,Wang, Liqiang,Liu, You-Nian
supporting information, p. 6252 - 6257 (2019/12/03)
Developing green, efficient, and low-cost catalysts for methylation of N-H by using CO2 as the C1 resource is highly desired yet remains a significant challenge. Herein, N-doped porous carbons (NPCs) were designed, synthesized, and proved to be an excellent metal-free catalyst for CO2-participated methylation conversion. NPCs were prepared via the pyrolysis of a mixture of tannic acid and urea. Both theoretical calculation and experiment demonstrate that the N species especially pyridinic N and pyrrolic N within NPCs can work as Lewis basic sites for attacking CO2 to weaken the CO bonds and lower the molecule conversion barrier, facilitating the subsequent methylation of N-H to produce, for example, N,N-dimethylaniline. Besides, the unique porous structure can enrich CO2 and accelerate mass transfer, synergistically promoting the conversion of CO2. The optimized NPC(1/5) catalyst, integrating the porous structure and strong Lewis basicity, exhibits excellent catalytic activity for CO2-based methylation reaction under mild conditions (1 bar CO2, 75 °C). Our work, for the first time, demonstrates the feasibility of using NPCs to catalyze the methylation of amino compounds to produce N,N-dimethylamine by exploiting CO2 as the C1 resource.
Gold Particles Supported on Amino-Functionalized Silica Catalyze Transfer Hydrogenation of N-Heterocyclic Compounds
Vilhanová, Beáta,van Bokhoven, Jeroen A.,Ranocchiari, Marco
supporting information, p. 677 - 686 (2017/02/23)
In this work we demonstrate that exceptionally small gold particles (d=0.6±0.2 nm) supported on amino-functionalized mesoporous silicate SBA-15 are highly active in transfer hydrogenation of structurally diverse unsaturated N-heterocyclic compounds. The heterocyclic ring is reduced selectively. The gold particles aggregate to a diameter of 4–5 nm in the presence of formic acid/triethylamine (hydrogen donor) during the first catalytic run. In subsequent cycles the nanoparticles maintain their size, yielding a very stable catalytic system that was recycled more than five times. In contrast, analogous SBA catalysts featuring larger (～5–35 nm) gold particles are not active. Excess formic acid also leads to the formation of formamide derivatives of the products of hydrogenation, which can be deformylated quantitatively. Fifteen structurally different substrates, including the scaffolds of quinoline, isoquinoline, quinoxaline, acridine, phenanthroline, quinazoline, and phenanthridine are hydrogenated and deformylated to give the amine products in >90% overall yield. Deuterium labeling experiments indicate that 1,2-addition with subsequent disproportionation of the formed intermediate is the preferred reaction path over the 1,4-addition one, suggesting the participation of a gold hydride species. (Figure presented.).
Heterogeneous gold-catalyzed selective reductive transformation of quinolines with formic acid
Tao, Lei,Zhang, Qi,Li, Shu-Shuang,Liu, Xiang,Liu, Yong-Mei,Cao, Yong
supporting information, p. 753 - 760 (2015/03/18)
Single phase rutile titania supported gold nanoparticles (Au/TiO2-R) are found to be efficient and versatile catalysts for chemo- and regioselective transfer hydrogenation of quinoline derivatives to 1,2,3,4-tetrahydroquinolines (THQs) using formic acid (FA) as a safe and convenient hydrogen source under mild conditions. The activity and chemoselectivity of the Au/TiO2-R catalyst towards THQs is excellent, with a substrate to catalyst ratio (S/C) of 1000 being feasible. Furthermore, a straightforward and selective route to N-formyltetrahydroquinolines (FTHQ) directly from quinoline compounds and FA by one-pot, gold-catalyzed reductive N-formylation protocol is also established.
Tungstate-Catalyzed Oxidation of Tetrahydroquinolines with Hydrogen Peroxide: A Novel Method for the Synthesis of Cyclic Hydroxamic Acids
Murahashi, Shun-Ichi,Oda, Tetsuya,Sugahara, Toshiaki,Masui, Yoshiyuki
, p. 1744 - 1749 (2007/10/02)
The sodium tungstate catalyzed oxidation of 1,2,3,4-tetrahydroquinolines (1) with 30percent aqueous hydrogen peroxide solution in methanol gives 1-hydroxy-3,4-dihydroquinolin-2(1H)-ones (2), which are important biologically active compounds, in good to excellent yields.The cyclic hydroxamic acid 7 is also obtained in good yield.Since reduction of 2 thus obtained gives 3,4-dihydroquinolin-2(1H)-ones (4), the present reaction provides a convenient method for synthesis of 4 from 1.
A Convenient Preparation of N-Acyl-1,2-dihydroquinoline
Katayama, Hajime,Ohkoshi, Mitsuko,Yasue, Masaiti
, p. 2226 - 2228 (2007/10/02)
N-Acetyl- and N-formyl-1,2-dihydroquinolone were conviniently prepared by reductive acylation of quinoline without isolating the labile 1,2-dihydroquinoline.This method was also applied to isoquinoline to prepare N-acetyl-1,2-dihydroisoquinoline.
