58960-03-5Relevant articles and documents
Heterogeneous Hydrogenation of Quinoline Derivatives Effected by a Granular Cobalt Catalyst
Timelthaler, Daniel,Topf, Christoph
, p. 629 - 642 (2021/11/22)
We communicate a convenient method for the pressure hydrogenation of quinolines in aqueous solution by using a particulate cobalt-based catalyst that is prepared in situ from simple Co(OAc)2 4H2O through reduction with abundant zinc powder. This catalytic protocol permits a brisk and atom-efficient access to a variety of 1,2,3,4-tetrahydroquinolines thereby relying solely on easy-to-handle reagents that are all readily obtained from commercial sources. Both the reaction setup assembly and the autoclave charging procedure are conducted on the bench outside an inert-gas-operated containment system, thus rendering the overall synthesis time-saving and operationally very simple.
Homogeneous pressure hydrogenation of quinolines effected by a bench-stable tungsten-based pre-catalyst
Heizinger, Christian,Topf, Christoph,Vielhaber, Thomas
, p. 451 - 461 (2021/11/11)
We report on an operationally simple catalytic method for the tungsten-catalyzed hydrogenation of quinolines through the use of the easily handled and self-contained precursor [WCl(η5-Cp)(CO)3]. This half sandwich complex is indefinitely storable on the bench in simple screw-capped bottles or stoppered flasks and can, if required, be prepared on a multi-gram scale while the actual catalytic transformations were performed in the presence of a Lewis acid in order to achieve both decent substrate conversions and product yields. The described method represents a facile and atom-efficient access to a variety of 1,2,3,4-tetrahydroquinolines that circumvents the use of cost-intensive and oxygen-sensitive phosphine ligands as well as auxiliary hydride reagents.
Utilization of renewable formic acid from lignocellulosic biomass for the selective hydrogenation and/or N-methylation
Zhou, Chao-Zheng,Zhao, Yu-Rou,Tan, Fang-Fang,Guo, Yan-Jun,Li, Yang
, p. 4724 - 4728 (2021/09/06)
Lignocellulosic biomass is one of the most abundant renewable sources in nature. Herein, we have developed the utilization of renewable formic acid from lignocellulosic biomass as a hydrogen source and a carbon source for the selective hydrogenation and further N-methylation of various quinolines and the derivatives, various indoles under mild conditions in high efficiencies. N-methylation of various anilines is also developed. Mechanistic studies indicate that the hydrogenation occurs via a transfer hydrogenation pathway.
Cu-Catalyzed Chemoselective Reduction of N-Heteroaromatics with NH3·BH3 in Aqueous Solution
Gao, Chao,Xuan, Qingqing,Song, Qiuling
supporting information, p. 2504 - 2508 (2021/07/31)
An efficient catalytic system was successfully developed on reduction of N-heteroaromatics with H3N?BH3 as hydrogen source in CuSO4 solution, featuring excellent chemoselectivity as well as very broad functional group tolerance. Various challenging substrates, such as OH-, NH2-, Cl-, Br-, etc., contained quinolines, quinoxalines, 1,5-naphthyridines and quinazolines were all reduced smoothly. Mechanistic studies suggested that [Cu-H] intermediate might be generated from NH3?BH3, which was believed to form with H3N?BH3 in CuSO4 solution.
Catalytic Hydrogenation of Substituted Quinolines on Co–Graphene Composites
Asaula, Vitalii M.,Buryanov, Volodymyr V.,Solod, Bohdan Y.,Tryus, Daryna M.,Pariiska, Olena O.,Kotenko, Igor E.,Volovenko, Yulian M.,Volochnyuk, Dmitriy M.,Ryabukhin, Sergey V.,Kolotilov, Sergey V.
, p. 6616 - 6625 (2021/12/24)
A set of 20 composites was prepared by pyrolysis of Co2+ complexes with 1,10-phenanthroline, melamine and 1,2-diaminobenzene. These composites were tested as the catalysts for the hydrogenation of quinolines. As shown by powder X-ray diffraction and TEM, the composited contained Co particles of several dozen nm sizes. The composition (elements content), Raman spectra X-ray photoelectron spectra parameters of the composites were analyzed. It was found that there was no distinct factor that controlled the yield of 1,2,3,4-tetrahydroquinolines in the investigated process. The yields of the respective products were in the range 90–100 %. The three most active composites were selected for scale-up and hydrogenation of a series of substituted quinolines. Up to 97 % yield of 1,2,3,4-tetrahydroquinoline was obtained on a 50 g scale. Five representative substituted quinolines were synthesized on a 10–20 grams scale using the Co-containing composites as the catalysts.
Discovery of tetrahydroquinolines and benzomorpholines as novel potent RORγt agonists
Xia, Yuehan,Yu, Mingcheng,Zhao, Yunpeng,Xia, Li,Huang, Yafei,Sun, Nannan,Song, Meiqi,Guo, Huimin,Zhang, Yunyi,Zhu, Di,Xie, Qiong,Wang, Yonghui
, (2020/12/04)
The retinoic acid receptor-related orphan receptor γt (RORγt) is an important nuclear receptor that regulates the differentiation of Th17 cells and production of interleukin 17(IL-17). RORγt agonists increase basal activity of RORγt and could provide a potential approach to cancer immunotherapy. Herein, hit compound 1 was identified as a weak RORγt agonist during in-house library screening. Changes in LHS core of 1 led to the identification of tetrahydroquinoline compound 6 as a partial RORγt agonist (max. act. = 39.3%). Detailed structure-activity relationship on substituent of the LHS core, amide linker and RHS arylsulfonyl moiety was explored and a novel series of tetrahydroquinolines and benzomorpholines was discovered as potent RORγt agonists. Tetrahydroquinoline compound 8g (EC50 = 8.9 ± 0.4 nM, max. act. = 104.5%) and benzomorpholine compound 9g (EC50 = 7.5 ± 0.6 nM, max. act. = 105.8%) were representative compounds with high RORγt agonistic activity in dual FRET assay, and they showed good activity in cell-based Gal4 reporter gene assay and Th17 cell differentiation assay (104.5% activation at 300 nM of 8g; 59.4% activation at 300 nM of 9g). The binding modes of 8g and 9g as well as the two RORγt inverse agonists accidentally discovered were also discussed.
One-pot dual catalysis for the hydrogenation of heteroarenes and arenes
Chatterjee, Basujit,Kalsi, Deepti,Kaithal, Akash,Bordet, Alexis,Leitner, Walter,Gunanathan, Chidambaram
, p. 5163 - 5170 (2020/09/07)
A simple dinuclear monohydrido bridged ruthenium complex [{(η6-p-cymene)RuCl}2(μ-H-μ-Cl)] acts as an efficient and selective catalyst for the hydrogenation of various heteroarenes and arenes. The nature of the catalytically active species was investigated using a combination of techniques including in situ reaction monitoring, kinetic studies, quantitative poisoning experiments and electron microscopy, evidencing a dual reactivity. The results suggest that the hydrogenation of heteroarenes proceeds via molecular catalysis. In particular, monitoring the reaction progress by NMR spectroscopy indicates that [{(η6-p-cymene)RuCl}2(μ-H-μ-Cl)] is transformed into monomeric ruthenium intermediates, which upon subsequent activation of dihydrogen and hydride transfer accomplish the hydrogenation of heteroarenes under homogeneous conditions. In contrast, carbocyclic aryl motifs are hydrogenated via a heterogeneous pathway, by in situ generated ruthenium nanoparticles. Remarkably, these hydrogenation reactions can be performed using molecular hydrogen under solvent-free conditions or with 1,4-dioxane, and thus give access to a broad range of saturated heterocycles and carbocycles while generating no waste.
Simple manganese carbonyl catalyzed hydrogenation of quinolines and imines
Wang, Zelong,Chen, Lei,Mao, Guoliang,Wang, Congyang
, p. 1890 - 1894 (2020/03/04)
Manganese-catalyzed hydrogenation of unsaturated molecules has made tremendous progresses recently benefiting from non-innocent pincer or bidentate ligands for manganese. Herein, we describe the hydrogenation of quinolines and imines catalyzed by simple manganese carbonyls, Mn2(CO)10 or MnBr(CO)5, thus eliminating the prerequisite pincer-type or bidentate ligands.
Au Nanoparticles Confined in SBA-15 as a Highly Efficient and Stable Catalyst for Hydrogenation of Quinoline to 1,2,3,4-Tetrahydroquinoline
Zhao, Jianbo,Yuan, Haifeng,Qin, Xiaomei,Tian, Kuan,Liu, Yingfan,Wei, Chengzhen,Zhang, Zhiqiang,Zhou, Liming,Fang, Shaoming
, p. 2841 - 2849 (2020/03/30)
Abstract: Au nanoparticles confined within the mesopores of the modified SBA-15 were obtained through adsorption-reduction method and firstly employed as chemoselective catalyst for quinoline hydrogenation. The effects of Au loadings, calcination temperature as well as structure of support on catalytic performances of Au catalysts were explored. The as-obtained 1.2percentAu@SBA-15-500 catalyst exhibited high activity, excellent selectivity towards 1,2,3,4-tetrahydroquinoline and extraordinary sintering-resistant property as high as 800?°C, which is sharp contrast to the 1.3percentAu/SiO2-500 catalyst. It also showed good recyclability and versatility for quinoline derivatives. The observed properties were assigned to small-sized Au nanoparticles and mesopores of SBA-15. Our work provides a facile and promising approach to construct metal nanocatalysts with high catalytic performance by the use of mesoporous materials. Graphic Abstract: [Figure not available: see fulltext.].
O-benzoylhydroxylamines as alkyl nitrene precursors: Synthesis of saturated N-heterocycles from primary amines
Noda, Hidetoshi,Asada, Yasuko,Shibasaki, Masakatsu
supporting information, p. 8769 - 8773 (2020/10/12)
We introduce O-benzoylhydroxylamines as competent alkyl nitrene precursors. The combination of readily available, stable substrates and a proficient rhodium catalyst provides a straightforward means for the construction of various pyrrolidine rings from the corresponding primary amines. Preliminary mechanistic investigation suggests that the structure of the nitrene precursor plays a role in determining the nature of the resulting reactive intermediate.
