635-46-1Relevant articles and documents
Correction to: Halogen-Bonding-Induced Hydrogen Transfer to C=N Bond with Hantzsch Ester (Org. Lett. (2014) 16:12 (3244-3247) DOI: 10.1021/ol501259q)
He, Wei,Ge, Yi-Cen,Tan, Choon-Hong
, p. 7684 - 7684 (2019)
The structure of C1 has been revised in the Graphical Abstract/Table of Contents graphic.(Figure presented)
Medium-Sized-Ring Analogues of Dibenzodiazepines by a Conformationally Induced Smiles Ring Expansion
Costil, Romain,Lefebvre, Quentin,Clayden, Jonathan
, p. 14602 - 14606 (2017)
Analogues of dibenzodiazepines, in which the seven-membered nitrogen heterocycle is replaced by a 9–12-membered ring, were made by an unactivated Smiles rearrangement of five- to eight-membered heterocyclic anthranilamides. The conformational preference of the tertiary amide in the starting material leads to intramolecular migration of a range of aryl rings, even those lacking electron-withdrawing activating groups, and provides a method for n→n+4 ring expansion. The medium-ring products adopt a chiral ground state with an intramolecular, transannular hydrogen bond. The rate of interconversion of their enantiomeric conformers depends on solvent polarity. Ring size and adjacent steric hindrance modulate this hidden hydrophilicity, thus making this scaffold a good candidate for drug development.
Study of Hydrodesulfurization by the Use of 35S-Labeled Dibenzothiophene. 2. Behavior of Sulfur in HDS, HDO, and HDN on Sulfided Mo/Al2O3 Catalyst
Kabe, Toshiaki,Quian, Weihua,Ishihara, Atsushi
, p. 912 - 916 (1994)
To investigate the behavior of sulfur during the hydrodesulfurization (HDS), 35S-labeled dibenzothiophene (DBT) was reacted on sulfided Mo/Al2O3.It was found that 35S in DBT was accommodated on the catalyst and the concentration of 35S on the catalyst always reached a steady state under fixed reaction conditions. 35S accommodated on the catalyst cannot be removed without the incorporation of sulfur from HDS of sulfur compounds such as DBT, benzothiophene, thiophene, and thiophenol.The removal rate of 35S from the catelyst depended upon the rate of HDS of these compounds, that is, the amount of sulfur incorporated into the catalyst.It was suggested that H2S is formed from some portion of sulfur on the surface of the catalyst othe than from that in the sulfur compounds.When hydrodenitrogenation (HDN) and hydrodeoxygenation (HDO) reactions were carried out on the catalyst containing 35S, some portion of 35S could be replaced by oxygen atoms and released as H2S; in contrast to this, 35S was hardly replaced by N atoms.
Chemoselective and Tandem Reduction of Arenes Using a Metal–Organic Framework-Supported Single-Site Cobalt Catalyst
Antil, Neha,Kumar, Ajay,Akhtar, Naved,Begum, Wahida,Chauhan, Manav,Newar, Rajashree,Rawat, Manhar Singh,Manna, Kuntal
supporting information, p. 1031 - 1040 (2022/01/19)
The development of heterogeneous, chemoselective, and tandem catalytic systems using abundant metals is vital for the sustainable synthesis of fine and commodity chemicals. We report a robust and recyclable single-site cobalt-hydride catalyst based on a porous aluminum metal–organic framework (DUT-5 MOF) for chemoselective hydrogenation of arenes. The DUT-5 node-supported cobalt(II) hydride (DUT-5-CoH) is a versatile solid catalyst for chemoselective hydrogenation of a range of nonpolar and polar arenes, including heteroarenes such as pyridines, quinolines, isoquinolines, indoles, and furans to afford cycloalkanes and saturated heterocycles in excellent yields. DUT-5-CoH exhibited excellent functional group tolerance and could be reusable at least five times without decreased activity. The same MOF-Co catalyst was also efficient for tandem hydrogenation–hydrodeoxygenation of aryl carbonyl compounds, including biomass-derived platform molecules such as furfural and hydroxymethylfurfural to cycloalkanes. In the case of hydrogenation of cumene, our spectroscopic, kinetic, and density functional theory (DFT) studies suggest the insertion of a trisubstituted alkene intermediate into the Co–H bond occurring in the turnover limiting step. Our work highlights the potential of MOF-supported single-site base–metal catalysts for sustainable and environment-friendly industrial production of chemicals and biofuels.
Dehydrogenative and Redox-Neutral N-Heterocyclization of Aminoalcohols Catalyzed by Manganese Pincer Complexes
Brzozowska, Aleksandra,Rueping, Magnus,Sklyaruk, Jan,Zubar, Viktoriia
, (2022/03/17)
A new manganese catalyzed heterocyclization of aminoalcohols has been accomplished. A wide range of heterocycles were synthesized, including 1,2,3,4-tetrahydroquinolines, dihydroquinolinones, and 2,3,4,5-tetrahydro-1H-benzo[b]azepines. The reaction is performed under mild reaction conditions using air and moisture stable manganese catalysts. The desired heterocycles were obtained in good to excellent yields.
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.
CO2-tuned highly selective reduction of formamides to the corresponding methylamines
Chao, Jianbin,Guo, Zhiqiang,Pang, Tengfei,Wei, Xuehong,Xi, Chanjuan,Yan, Leilei
supporting information, p. 7534 - 7538 (2021/10/12)
We herein describe an efficient, CO2-tuned and highly selective C-O bond cleavage of N-methylated formanilides. With easy-to-handle and commercially available NaBH4 as the reductant, a variety of formanilides could be turned into the desired tertiary amines in moderate to excellent yields. The role of CO2 has been investigated in detail, and the mechanism is proposed on the basis of experiments.
Zirconium-hydride-catalyzed site-selective hydroboration of amides for the synthesis of amines: Mechanism, scope, and application
Han, Bo,Jiao, Haijun,Wu, Lipeng,Zhang, Jiong
, p. 2059 - 2067 (2021/09/02)
Developing mild and efficient catalytic methods for the selective synthesis of amines is a longstanding research objective. In this respect, catalytic deoxygenative amide reduction has proven to be promising but challenging, as this approach necessitates selective C–O bond cleavage. Herein, we report the selective hydroboration of primary, secondary, and tertiary amides at room temperature catalyzed by an earth-abundant-metal catalyst, Zr-H, for accessing diverse amines. Various readily reducible functional groups, such as esters, alkynes, and alkenes, were well tolerated. Furthermore, the methodology was extended to the synthesis of bio- and drug-derived amines. Detailed mechanistic studies revealed a reaction pathway entailing aldehyde and amido complex formation via an unusual C–N bond cleavage-reformation process, followed by C–O bond cleavage.
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.
Palladium supported on magnesium hydroxyl fluoride: An effective acid catalyst for the hydrogenation of imines and N-heterocycles
Agbossou-Niedercorn, Francine,Corre, Yann,Dongare, Mohan K.,Kemnitz, Erhard,Kokane, Reshma,Michon, Christophe,Umbarkar, Shubhangi B.
supporting information, p. 19572 - 19583 (2021/11/04)
Palladium catalysts supported on acidic fluorinated magnesium hydroxide Pd/MgF2-x(OH)x were prepared through precipitation or impregnation methods. Applications to the hydrogenation of various aldimines and ketimines resulted in good catalytic activities at mild temperatures using one atmosphere of hydrogen. Quinolines, pyridines and other N-heterocycles were successfully hydrogenated at higher temperature and hydrogen pressure using low palladium loadings and without the use of any acid additive. Such reactivity trend confirmed the positive effect of the Br?nsted and Lewis acid sites from the fluorinated magnesium hydroxide support resulting in the effective pre-activation of N-heterocycle substrates and therefore in the good catalytic activity of the palladium nanoparticles during the hydrogenations. As demonstrated in the hydrogenation of imines, the catalyst was recycled up to 10 times without either loss of activity or palladium leaching. This journal is
