24463-30-7Relevant academic research and scientific papers
Phosphane-decorated Platinum Nanoparticles as Efficient Catalysts for H2 Generation from Ammonia Borane and Methanol
Lara, Patricia,Philippot, Karine,Suárez, Andrés
, p. 766 - 771 (2019)
A series of narrowly dispersed Pt nanoparticles of 1.5–2.2 nm in size stabilized by bulky terphenylphosphane ligands has been synthesized by the organometallic method using [Pt(dba)2] as platinum source. These nanoparticles are highly efficient catalysts for hydrogen generation by methanolysis of ammonia borane (H3N ? BH3), providing notable TOF values of up to 284 min?1 at 30 °C and low catalyst loadings (0.14–0.19 mol %). Furthermore, catalyst separation (after distillation of the H2-depleted ammonium tetramethoxyborate (NH4B(OMe)4) and methanol) and recycling were proven to be feasible, although an erosion of the catalytic activity was observed after three catalytic runs. These Pt nanoparticles have also been used as catalysts for tandem dehydrogenation of ammonia borane and hydrogenation of N-heterocycles, providing the reduction products of quinoline, phenanthridine, 2-methylquinoxaline and acridine in >90 % yields under mild reaction conditions.
Dendrimer-Stabilized Metal Nanoparticles as Efficient Catalysts for Reversible Dehydrogenation/Hydrogenation of N-Heterocycles
Deraedt, Christophe,Ye, Rong,Ralston, Walter T.,Toste, F. Dean,Somorjai, Gabor A.
, p. 18084 - 18092 (2017)
Nanoparticles (Pd, Pt, Rh) stabilized by G4OH PAMAM dendrimers and supported in SBA-15 (MNPs/SBA-15 with M = Pd, Pt, Rh) were efficiently used as catalysts in the acceptorless dehydrogenation of tetrahydroquinoline/indoline derivatives in toluene (release of H2) at 130 °C. These catalysts are air stable, very active, robust, and recyclable during the process. The reverse hydrogenation reaction of quinoline derivatives (H2 storage) was also optimized and successfully performed in the presence of the same catalysts in toluene at 60 °C under only 1 atm of hydrogen gas. Such catalysts may be essential for the adoption of organic hydrogen-storage materials as an alternative to petroleum-derived fuels. Hot filtration test confirmed that the reaction follows a heterogeneous pathway. Moreover, PdNPs/SBA-15 was an excellent catalyst for the direct arylation at the C-2 position (via C-H activation) of indole in water in the presense of a hypervalent iodine oxidant. Thus, a one-pot dehydrogenation/direct arylation cascade reaction between indoline and an arylated agent was efficaciously performed in water, demonstrating the potential of the system to catalyze tandem heterogeneous/homogeneous processes by choice of the appropriate oxidant/reductant.
Rhodium(III)-Catalyzed Oxidative Annulation of 2,2′-Bipyridine N-Oxides with Alkynes via Dual C-H Bond Activation
Xu, Xin,Zhao, Haoqiang,Xu, Jianbin,Chen, Changjun,Pan, Yixiao,Luo, Zhenli,Zhang, Zongyao,Li, Huanrong,Xu, Lijin
, p. 3843 - 3847 (2018)
Rh(III)-catalyzed switchable annulation of 2,2′-bipyridine N-oxides with internal alkynes via dual C-H bond activation has been developed. Tuning the reaction conditions enabled the reaction pathway to be switched between rollover and nonrollover annulation, delivering 5,6-disubstituted-1,10-phenanthrolines and 5,6,7,8-tetrasubstituted-1-(pyridin-2-yl)isoquinoline 2-oxides in high yields, respectively. The procedures feature excellent regioselectivity, broad substrate scope, and high tolerance of functional groups. The synthetic utilities of these obtained products were demonstrated in the catalytic reactions.
Tetrabutylammonium Bromide-Catalyzed Transfer Hydrogenation of Quinoxaline with HBpin as a Hydrogen Source
Guo, Qi,Chen, Jingchao,Shen, Guoli,Lu, Guangfu,Yang, Xuemei,Tang, Yan,Zhu, Yuanbin,Wu, Shiyuan,Fan, Baomin
supporting information, p. 540 - 546 (2021/12/27)
A metal-free environmentally benign, simple, and efficient transfer hydrogenation process of quinoxaline has been developed using the HBpin reagent as a hydrogen source. This reaction is compatible with a variety of quinoxalines offering the desired tetrahydroquinoxalines in moderate-to-excellent yields with Bu4NBr as a noncorrosive and low-cost catalyst.
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.
A quantum-chemical approach to develop tetrahydroquinoxaline as potent ferroptosis inhibitors
Lei, Hong-Xu,Zhang, KaiLi,Qin, Yu-Xi,Dong, Rong-Jian,Chen, De-Zhan,Zhou, HaiFeng,Sheng, Xie-Huang
, (2020/11/10)
Ferroptosis is a recently characterized form of regulated necrosis with the iron-dependent accumulation of (phospho)lipid hydroperoxides (LOOH). It has attracted considerable attention for its putative involvement in diverse pathophysiological processes, such as cardiovascular disease and neurodegeneration. Here we describe the discovery of tetrahydroquinoxaline, a novel scaffold of ferroptosis inhibitors based on quantum chemistry methods. Tetrahydroquinoxaline deviates showed very good inhibition of ferroptosis, while being non cytotoxic for human cancer cells. And, the advantage of them is their small molecular weight (MW. = 148 Da) that can be coupled with other drugs to form multi-target drugs to better meet the treatment of complicated diseases.
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.
Hydrogenation or Dehydrogenation of N-Containing Heterocycles Catalyzed by a Single Manganese Complex
Borghs, Jannik C.,Rueping, Magnus,Zubar, Viktoriia
supporting information, (2020/05/19)
A highly chemoselective base-metal catalyzed hydrogenation and acceptorless dehydrogenation of N-heterocycles is presented. A well-defined Mn complex operates at low catalyst loading (as low as 2 mol %) and under mild reaction conditions. The described catalytic system tolerates various functional groups, and the corresponding reduced heterocycles can be obtained in high yields. Experimental studies indicate a metal-ligand cooperative catalysis mechanism.
Hydrogenation/dehydrogenation of N-heterocycles catalyzed by ruthenium complexes based on multimodal proton-responsive CNN(H) pincer ligands
álvarez, Eleuterio,Hernández-Juárez, Martín,López-Serrano, Joaquín,Paneque, Margarita,Rendón, Nuria,Sánchez, Práxedes,Santos, Laura L.,Suárez, Andrés
supporting information, p. 9583 - 9587 (2020/07/30)
Ru complexes based on lutidine-derived pincer CNN(H) ligands having secondary amine side donors are efficient precatalysts in the hydrogenation and dehydrogenation of N-heterocycles. Reaction of a Ru-CNN(H) complex with an excess of base produces the formation of a Ru(0) derivative, which is observed under catalytic conditions.
