- Photoinduced Reduction of Nitroarenes Using a Transition-Metal-Loaded Silicon Semiconductor under Visible Light Irradiation
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We investigated transition-metal-loaded silicon nanoparticles for the photocatalytic reduction of nitroarene derivatives in the presence of formic acid under visible light irradiation. Formic acid assumes the role of both a hydrogen source and a sacrificial reagent for the introduction of electrons into the generated holes of semiconductors. As such, in the presence of formic acid, photocatalytic reactions smoothly proceed under mild conditions without gaseous hydrogen. In particular, palladium-loaded silicon (Pd/Si) was the most suitable catalyst for the conversion of nitrobenzene to aniline, compared to Pt/Si, Ru/Si, and Pd/C.
- Tsutsumi, Ken,Uchikawa, Fumito,Sakai, Kentaro,Tabata, Kenji
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- PqsBC, a condensing enzyme in the biosynthesis of the pseudomonas aeruginosa quinolone signal: Crystal structure, inhibition, and reaction mechanism
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Pseudomonas aeruginosa produces a number of alkylquinolone- type secondary metabolites best known for their antimicrobial effects and involvement in cell-cell communication. In the alkylquinolone biosynthetic pathway, the β-ketoacyl-(acyl carrier protein) synthase III (FabH)-like enzyme PqsBC catalyzes the condensation of octanoyl-coenzyme A and 2-aminobenzoylacetate (2-ABA) to form the signal molecule 2-heptyl- 4(1H)-quinolone. PqsBC, a potential drug target, is unique for its heterodimeric arrangement and an active site different from that of canonical FabH-like enzymes. Considering the sequence dissimilarity between the subunits, a key question was how the two subunits are organized with respect to the active site. In this study, the PqsBC structure was determined to a 2 A¢ resolution, revealing that PqsB and PqsC have a pseudo-2-fold symmetry that unexpectedly mimics the FabH homodimer. PqsC has an active site composed of Cys-129 and His-269, and the surrounding active site cleft is hydrophobic in character and approximately twice the volume of related FabH enzymes that may be a requirement to accommodate the aromatic substrate 2-ABA. From physiological and kinetic studies, we identified 2-aminoacetophenone as a pathway-inherent competitive inhibitor of PqsBC, whose fluorescence properties could be used for in vitro binding studies. In a time-resolved setup,wedemonstrated that the catalytic histidine is not involved in acyl-enzyme formation, but contributes to an acylation-dependent increase in affinity for the second substrate 2-ABA. Introduction of Asn into the PqsC active site led to significant activity toward the desamino substrate analog benzoylacetate, suggesting that the substrate 2-ABA itself supplies the asparagine- equivalent amino function that assists in catalysis.
- Drees, Steffen Lorenz,Li, Chan,Prasetya, Fajar,Saleem, Muhammad,Dreveny, Ingrid,Williams, Paul,Hennecke, Ulrich,Emsley, Jonas,Fetzner, Susanne
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- Synthesis of functionalised 2,3-dihydroquinolin-4(1: H)-ones vs. quinoline or N -alkenylindole derivatives through sequential reactions of 2-alkynylanilines with ketones
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This study describes diversity-oriented synthesis of 2,2,3-substituted-2,3-dihydroquinolin-4(1H)-ones vs. functionalised quinoline or N-alkenylindole derivatives through Br?nsted acid mediated or Lewis acid catalyzed sequential reactions of 2-alkynylanilines with ketones. In particular, a series of challenging quinolin-4-one derivatives are prepared with good functional group tolerance in an atom-economical fashion by using p-toluenesulfonic acid monohydrate as a promoter of the reaction of ketones with 2-alkynylanilines in EtOH at reflux, while the same starting materials give the corresponding 4-substituted quinolines in toluene at 110 °C both in the presence of p-toluenesulfonic acid monohydrate as the promoter and FeCl3 as the catalyst. The divergent formation of N-alkenylindole derivatives occurs by switching to the use of ZnBr2 as the catalyst under the same reaction conditions. Conversely, only 4-methylsubstituted quinoline derivatives were isolated by reacting 2-ethynylanilines and/or 2-trimethylsylilanilines with ketones in all examined cases. This journal is
- Marsicano, Vincenzo,Arcadi, Antonio,Chiarini, Marco,Fabrizi, Giancarlo,Goggiamani, Antonella,Iazzetti, Antonia
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- Catalytic Synthesis of 3-Substituted Indoles using CO as Building Block and Supported Rhodium as Catalyst
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Under hydroformylation conditions, using supported rhodium as catalyst, 2-nitrostyrene is directly converted into skatole in ca. 70percent yield, by a reaction involving formation of 2-(o-nitrophenyl)propionaldehyde by homogeneous catalysis, reduction of the nitro-group by heterogeneous catalysis, then ring closure and thermal dehydration.
- Ucciani, Eugene,Bonfand, Andre
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- Selective hydrogenation of nitroarenes using an electrogenerated polyoxometalate redox mediator
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The 2-electron reduced form of the polyoxometalate silicotungstic acid (H4[SiW12O4]) is shown to be an effective and selective hydrogenation agent for a range of nitroarenes without the need for any co-catalyst. The ease of generation of the active species and its recyclability suggest that a new approach to this important class of chemical conversions is possible.
- Macdonald, Lewis,Rausch, Benjamin,Symes, Mark D.,Cronin, Leroy
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- High catalytic activity of a bimetallic AgPd alloy supported on UiO-66 derived porous carbon for transfer hydrogenation of nitroarenes using formic acid-formate as the hydrogen source
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Bimetallic AgPd nanoparticles anchored on metal-organic framework (UiO-66) derived N-doped porous carbon (NPC-UiO-66) was fabricated and used as a catalyst for the catalytic transfer hydrogenation of nitroarenes using formic acid-formate as the hydrogen source. The results demonstrated that the Ag1Pd9@NPC-UiO-66 composite exhibited extraordinary catalytic activity toward the hydrogenation of nitroarenes to anilines at room temperature. A series of substituted nitroarenes were successfully converted to the corresponding anilines in high yields under ambient conditions with other reducible groups remaining intact. The superior catalytic performance of the prepared catalyst can be attributed to the synergistic effect between the highly dispersed AgPd nanoparticles and the unique structure of the NPC-UiO-66 support, as well as the high adsorption ability of the catalyst for the nitroarenes.
- Cheng, Saisai,Shang, Ningzhao,Zhou, Xin,Feng, Cheng,Gao, Shutao,Wang, Chun,Wang, Zhi
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- A facile reduction of aromatic nitro compounds to aromatic amines with bis(cyclopentadienyl)titanium(IV) dichloride-indium system
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Cp2TiCl2/In system was found to be a new reagent for reducing various aromatic nitro compounds to the corresponding aromatic amines in good yields under mild and neutral conditions.
- Yoo, Byung Woo,Lee, Sung Jae,Yoo, Byoung Seung,Choi, Kyung Il,Kim, Joong Hyup
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- Palladium(II)-mediated oxidative cyclization of N-carbamoyl aminoalkynes: A new route to γ-lactams
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Transformation of N-carbamoyl or acetyl-4-trimethylsilyl-3-alkyn-1-amines to diversely substituted 2-pyrrolidinones, via a Wacker-type reaction, is described.
- Doan, Huynh Dong,Gore, Jacques,Vatele, Jean-Michel
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- Pd nanoparticles supported on a covalent triazine-based framework material: An efficient and highly chemoselective catalyst for the reduction of nitroarenes
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Pd nanoparticles anchored on a covalent triazine framework (Pd@CTF) were fabricated and employed to catalyze the transfer hydrogenation of nitro-compounds with formic acid as the hydrogen source. The results demonstrated that Pd@CTF displayed excellent catalytic activity and high chemoselectivity for the hydrogenation reaction at room temperature. Various substituted nitro-compounds were successfully converted to the corresponding amines in 0.2-2.5 h with other reducible functional moieties remaining intact. The high performance of Pd@CTF can be attributed to the synergistic interaction between the highly dispersed Pd nanoparticles and the covalent triazine framework support. The Pd@CTF catalyst can be readily reused for at least five consecutive runs without an obvious loss of its catalytic activity.
- Li, Jie,Zhang, Lihong,Liu, Xiaotong,Shang, Ningzhao,Gao, Shutao,Feng, Cheng,Wang, Chun,Wang, Zhi
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- Intercalating ultrathin polymer interim layer for charge transfer cascade towards solar-powered selective organic transformation
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Transition metal chalcogenide quantum dots (TMCs QDs) constitute a crucial sector of semiconductors on account of large absorption coefficient for light harvesting, peculiar quantum confinement effect, and abundant active sites stemming from ultra-small size. However, elaborate and tunable modulation of anisotropic photoinduced charge carriers over TMCs QDs represents an enduring challenge in terms of sluggish charge transfer kinetic and ultra-short charge lifetime compared with nanoparticulate counterparts, thereby rendering maneuvering charge transfer of TMCs QDs a tough issue. We herein conceptually unlock the unanticipated charge transport capability of solid-state non-conductive poly(diallyl dimethylammonium chloride) (PDDA) for constructing cascade charge transfer pathway over self-assembled wide bandgap semiconductors (WBS)/PDDA/TMCs QDs multilayered heterostructures, by which unidirectional and accelerated electron transfer from TMCs QDs to WBS support mediums was spontaneously activated, markedly boosting the charge separation/migration efficiency. The integrated roles of such ultrathin insulating PDDA intermediate layer as simultaneous surface charge modifying agent and interfacial charge transfer mediator have been evidenced to be universal. The unexpected electron-withdrawing capability of ultrathin PDDA layer endows WBS (SnO2, TiO2)@PDDA@TMCs (CdSe, CdS) QDs heterostructures with significantly enhanced net efficiency of photoactivities toward selective anaerobic reduction of nitroaromatics to amino derivatives under visible light irradiation. Our work would feature a promising scope for rational design of multifarious novel insulating polymers-based photosystems for solar energy conversion.
- Fu, Xiao-Yan,Hou, Shuo,Lin, Hua-Jian,Lin, Xin,Mo, Qiao-Ling,Wei, Zhi-Quan,Xiao, Fang-Xing,Xu, Shuai
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- Confinement of Quantum Dots in between Monolayered Graphene Nanosheets for Arousing Boosted Multifarious Photoredox Selective Organic Transformation
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Transition metal chalcogenide quantum dots (TMC QDs) represent promising light-harvesting antennas because of their fascinating physicochemical properties including quantum confinement effect and suitable energy band structures. However, TMC QDs generally suffer from poor photoactivities and photostability due to deficiency of active sites and ultrafast recombination rate of photoinduced charge carriers. Here, we demonstrate how to rationally arouse the charge transfer kinetic of TMC QDs by close monolayered graphene (GR) encapsulation via a ligand-dominated layer-by-layer (LbL) assembly utilizing oppositely charged TMC QDs and GR nanosheets as the building blocks. The assembly units were spontaneously and intimately integrated in an alternate integration mode, thereby resulting in the multilayered three-dimensional (3D) TMC QDs/GR ensembles. It was unveiled that multifarious photoactivities of TMC QDs/GR nanocomposites toward versatile photoredox organic catalysis including photocatalytic aromatic alcohols oxidation to aldehydes and nitroaromatics reduction to amino derivatives under visible light irradiation are conspicuously boosted because of spatially multilayered monolayered GR encapsulation which are superior to those of TMC QDs counterparts. The substantially enhanced photoactivities of TMC QDs/GR nanocomposites arise from reasons including improved light absorption and enhanced charge separation efficacy because of GR encapsulation together with unique stacking mode between TMC QDs and GR endowed by LbL assembly. Our work would provide a promising and efficacious route to smartly accelerate the charge transfer kinetic of TMC QDs for solar energy conversion.
- Hou, Shuo,Huang, Ming-Hui,Li, Yu-Bing,Xu, Shuai,Lin, Xin,Fu, Xiao-Yan,Xiao, Fang-Xing
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- Hollow Nano-Mesosilica Spheres Containing Rhodium Nanoparticles Supported on Nitrogen-Doped Carbon: An Efficient Catalyst for the Reduction of Nitroarenes under Mild Conditions
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Atom efficiency, low temperature, low pressure, and a nontoxic hydrogen source as a reducing agent are ideal reaction conditions for the reduction of nitroarenes. In this work, an efficient catalyst comprising hollow nano-mesosilica spheres loaded with Rh nanoparticles supported on nitrogen-doped carbon was developed. Rh nanoparticles were stabilized and uniformly dispersed by nitrogen atoms, and the inner N-doped carbon shell was used to adsorb reaction substrates and improve catalytic activity. The catalyst showed remarkable activity (maximum yield at 1.5 h) and selectivity (100 %) for the reduction of nitrobenzene at lower temperature (80 °C), atmospheric pressure (1 atm), and without base under aqueous conditions. Moreover, the hydrothermal stability of this nanocatalyst was better than other catalysts in boiling water at 100 °C for 48 h and effectively prevented the aggregation and leaching of Rh NPs during the reaction.
- Wang, Shihan,Dai, Jinyu,Shi, Zhiqiang,Xiong, Zeshan,Zhang, Zongtao,Qiu, Shilun,Wang, Runwei
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- Catalytic Deoxygenation of Nitroarenes Mediated by High-Valent Molybdenum(VI)-NHC Complexes
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The high-valent molybdenum(VI) N-heterocyclic carbene complexes, (NHC)MoO2 (1) and (NHC)MoO(NtBu) (2) (NHC = 1,3-bis(3,5-di-tert-butyl-2-phenolato)-benzimidazol-2-ylidene), are investigated toward their catalytic potential in the deoxygenation of nitroarenes. Using pinacol as the sacrificial and green reductant, both complexes are shown to be very active (pre)catalysts for this transformation allowing a reduction of the catalyst loading down to 0.25 mol %. Mechanistic investigations show μ-oxo bridged molybdenum(V) complexes [(NHC)MoO]2O (4) and [(NHC)Mo(NtBu)]2O (5) as well as zwitterionic pinacolate benzimidazolium complex 6, with a doubly protonated NHC ligand, to be potentially active species in the catalytic cycle. Both 4 and 5 can be prepared independently by the deoxygenation of 1 and 2 using triethyl phosphine (PEt3) or triphenyl phosphine (PPh3) and were shown to exhibit an unusual multireferenced ground state with a very small singlet-triplet gap at room temperature. Computational studies show that the spin state plays an unneglectable role in the catalytic process, efficiently lowering the reaction barrier of the deoxygenation step. Mechanistic details, putting special emphasis on the fate of the catalyst will be presented and potential routes how nitroarene reduction is facilitated are evaluated.
- Liu, Shenyu,Amaro-Estrada, Jorge Ivan,Baltrun, Marc,Douair, Iskander,Schoch, Roland,Maron, Laurent,Hohloch, Stephan
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supporting information
p. 107 - 118
(2021/02/05)
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- Cobalt nanoclusters coated with N-doped carbon for chemoselective nitroarene hydrogenation and tandem reactions in water
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The development of active and selective non-noble metal-based catalysts for the chemoselective reduction of nitro compounds in aquo media under mild conditions is an attractive research area. Herein, the synthesis of subnanometric and stable cobalt nanoclusters, covered by N-doped carbon layers as core-shell (Co@NC-800), for the chemoselective reduction of nitroarenes is reported. TheCo@NC-800catalyst was prepared by the pyrolysis of the Co(tpy)2complex impregnated on Vulcan carbon. In fact, the use of a molecular complex based on six N-Co bonds drives the formation of a well-defined and distributed cobalt core-shell nanocluster covered by N-doped carbon layers. In order to elucidate its nature, it has been fully characterized by using several advanced techniques. In addition, this as-prepared catalyst showed high activity, chemoselectivity and stability toward the reduction of nitro compounds with H2and under mild reaction conditions; water was used as a green solvent, improving the previous results based on cobalt catalysts. Moreover, theCo@NC-800catalyst is also active and selective for the one-pot synthesis of secondary aryl amines and isoindolinones through the reductive amination of nitroarenes. Finally, based on diffraction and spectroscopic studies, metallic cobalt nanoclusters with surface CoNxpatches have been proposed as the active phase in theCo@NC-800material.
- Agostini, Giovanni,Calvino, Jose. J.,Corma, Avelino,Gutiérrez-Tarri?o, Silvia,Lopes, Christian W.,O?a-Burgos, Pascual,Rojas-Buzo, Sergio
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supporting information
p. 4490 - 4501
(2021/06/28)
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- Unlocking Amides through Selective C–N Bond Cleavage: Allyl Bromide-Mediated Divergent Synthesis of Nitrogen-Containing Functional Groups
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We report a new set of reactions based on the unlocking of amides through simple treatment with allyl bromide, creating a common platform for accessing a diverse range of nitrogen-containing functional groups such as primary amides, sulfonamides, primary amines, N-acyl compounds (esters, thioesters, amides), and N-sulfonyl esters. The method has potential industrial applicability, as demonstrated through gram-scale syntheses in batch and in a continuous flow system.
- Govindan, Karthick,Chen, Nian-Qi,Chuang, Yu-Wei,Lin, Wei-Yu
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supporting information
p. 9419 - 9424
(2021/11/30)
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- Metal-Free and syn-Selective Hydrohalogenation of Alkynes through a Pseudo-Intramolecular Process
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A new metal-free hydrohalogenation method for alkynes has been developed, which proceeds through a pseudo-intramolecular process. In this reaction, ethynylaniline serves as a substrate to quantitatively form an anilinium salt upon treatment with hydrochloric acid. The spatial proximity facilitates the efficient electrophilic addition of HCl to the ethynyl group in syn-mode, affording the corresponding chloroalkene without overaddition. This protocol was applied to HBr and HI, and the corresponding bromo- and iodoalkenes were obtained, respectively. The obtained chloroalkene was converted to tri-substituted alkenes possessing different aryl/alkynyl groups through Pd-catalyzed cross-coupling reactions.
- Asahara, Haruyasu,Mukaijo, Yusuke,Muragishi, Kengo,Iwai, Kento,Ito, Akitaka,Nishiwaki, Nagatoshi
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p. 5747 - 5755
(2021/10/20)
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- Highly selective hydrogenation of aromatic ketones to alcohols in water: effect of PdO and ZrO2
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Pd/ZrO2and PdO/ZrO2composites, containing Pd or PdO nanoparticles, were prepared using an original one-step methodology. These nanocomposites catalyze the hydrogenation of acetophenone (AP) at 1 bar and 10 bar of H2in an aqueous solution. Compared to unsupported Pd or PdO nanoparticles, a remarkable increase in their activity was achieved as a result of interaction with zirconia. An unsupported PdO hydrogenated AP mainly to ethylbenzene (EB), while excellent regioselectivity towards 1-phenylethanol (PE) was obtained with PdO/ZrO2and it was preserved during recycling. Similarly, regioselectivity to PE was higher with Pd/ZrO2compared to unsupported Pd NPs. PdO and zirconia resulted in high selectivity to alcohols in the hydrogenation of substituted acetophenones.
- Alsalahi, W.,Trzeciak, A. M.,Tylus, W.
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p. 10386 - 10393
(2021/08/09)
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- A Convenient Formal [4+2] Heterocylization Route to Bis(triflyl)tetrahydroquinolines
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We report the sustainable and efficient synthesis of a new type of quinoline derivatives bearing one or two SO2CF3 groups. The protocol is metal-, catalyst- and irradiation-free, involves the use of readily available and stable precursors, and avoids the formation of side products. Also, the mild conditions of the process allow the tolerance of a wide range of functional groups.
- Lázaro-Milla, Carlos,Almendros, Pedro
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supporting information
p. 13534 - 13538
(2021/08/13)
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- Rapid, chemoselective and mild oxidation protocol for alcohols and ethers with recyclable N-chloro-N-(phenylsulfonyl)benzenesulfonamide
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Chlorine is the 20th most abundant element on the earth compared to bromine, iodine, and fluorine, a sulfonimide reagent, N-chloro-N-(phenylsulfonyl)benzenesulfonamide (NCBSI) was identified as a mild and selective oxidant. Without activation, the reagent was proved to oxidize primary and secondary alcohols as well as their symmetrical and mixed ethers to corresponding aldehydes and ketones. With recoverable PS-TEMPO catalyst, selective oxidation over chlorination of primary and secondary alcohols and their ethers with electron-donating substituents was achieved. The reagent precursor of NCBSI was recovered quantitatively and can be reused for synthesizing NCBSI.
- Badani, Purav,Chaturbhuj, Ganesh,Ganwir, Prerna,Misal, Balu,Palav, Amey
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supporting information
(2021/06/03)
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- Copper-Catalyzed Chemoselective Cyclization Reaction of 2-Isocyanoacetophenone: Synthesis of 4-Hydroxyquinoline Compounds
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A copper-catalyzed intramolecular cyclization reaction of 2-isocyanoacetophenone derivatives to afford 4-hydroxyquinolines chemoselectively is described. The transformation proceeds through enol tautomerism and a subsequent C-C bond formation. Compared to previous methods, this study provides a new protocol for the construction of 4-hydroxyquinoline compounds from functionalized isocyanides under mild conditions.
- Yuan, Qing,Rao, Weidong,Wang, Shun-Yi,Ji, Shun-Jun
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p. 1279 - 1284
(2020/01/22)
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- Preparation method of O-aminoacetophenone
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The invention relates to the technical field of organic intermediate synthesis, in particular to a preparation method of o-aminoacetophenone. The preparation method of o-aminoacetophenone provided bythe invention comprises the following steps: adding potassium permanganate into o-nitroethylbenzene in batches in an acidic environment of dilute sulfuric acid to carry out oxidation reaction to generate o-nitroacetophenone; reducing the o-nitroacetophenone into o-aminoacetophenone by using iron powder; and distilling off o-aminoacetophenone by using water vapor. The reaction conditions are mild,the production cost is low, the method is suitable for industrial mass production, the yield of the o-nitroacetophenone can reach 70% or above, the yield of the o-aminoacetophenone can reach 90% or above, and the yield of the o-nitroacetophenone and the yield of the o-aminoacetophenone can both reach 95% or above when weak acid glacial acetic acid is adopted as a catalyst and all the raw materialsare kept in the optimal proportion and react under the optimal reaction condition.
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Paragraph 0037; 0039-0040; 0042-0043; 0045-0046; 0048-0049
(2020/09/30)
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- Hydrogenation reaction method
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The invention relates to a hydrogenation reaction method, and belongs to the technical field of organic synthesis. The hydrogenation reaction method provided by the invention comprises the following steps: carrying out a hydrogen transfer reaction on a hydrogen acceptor compound, pinacol borane and a catalyst in a solvent in the presence of proton hydrogen, so that the hydrogen acceptor compound is subjected to a hydrogenation reaction; the catalyst is one or more than two of a palladium catalyst, an iridium catalyst and a rhodium catalyst; the hydrogen acceptor compound comprises one or morethan two functional groups of carbon-carbon double bonds, carbon-carbon triple bonds, carbon-oxygen double bonds, carbon-nitrogen double bonds, nitrogen-nitrogen double bonds, nitryl, carbon-nitrogentriple bonds and epoxy. The method is mild in reaction condition, easy to operate, high in yield, short in reaction time, wide in substrate application range, suitable for carbon-carbon double bonds,carbon-carbon triple bonds, carbon-oxygen double bonds, carbon-nitrogen double bonds, nitrogen-nitrogen double bonds, nitryl, carbon-nitrogen triple bonds and epoxy functional groups, good in selectivity and high in reaction specificity.
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Paragraph 0034; 0305-0308
(2020/05/14)
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- Generalized Chemoselective Transfer Hydrogenation/Hydrodeuteration
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A generalized, simple and efficient transfer hydrogenation of unsaturated bonds has been developed using HBPin and various proton reagents as hydrogen sources. The substrates, including alkenes, alkynes, aromatic heterocycles, aldehydes, ketones, imines, azo, nitro, epoxy and nitrile compounds, are all applied to this catalytic system. Various groups, which cannot survive under the Pd/C/H2 combination, are tolerated. The activity of the reactants was studied and the trends are as follows: styrene'diphenylmethanimine'benzaldehyde'azobenzene'nitrobenzene'quinoline'acetophenone'benzonitrile. Substrates bearing two or more different unsaturated bonds were also investigated and transfer hydrogenation occurred with excellent chemoselectivity. Nano-palladium catalyst in situ generated from Pd(OAc)2 and HBPin extremely improved the TH efficiency. Furthermore, chemoselective anti-Markovnikov hydrodeuteration of terminal aromatic olefins was achieved using D2O and HBPin via in situ HD generation and discrimination. (Figure presented.).
- Wang, Yong,Cao, Xinyi,Zhao, Leyao,Pi, Chao,Ji, Jingfei,Cui, Xiuling,Wu, Yangjie
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supporting information
p. 4119 - 4129
(2020/08/10)
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- Method for synthesizing O-aminoacetophenone (by machine translation)
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The invention discloses a method for synthesizing a medical intermediate o-aminoacetophenone, wherein o-ethyl nitrobenzene is taken as a starting raw material, and the compound is obtained by reacting an ethyl oxide with a reducing nitro 2 step. To the synthesis method, o-aminoacetophenone is synthesized, a novel oxidizing agent and a reducing agent are adopted, the yield 56% is around, and the method has the characteristics of high process safety, low material price, easiness in production and amplification and the like. (by machine translation)
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Paragraph 0038; 0050-0054; 0057; 0063-0066
(2020/09/20)
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- Transfer Hydrogenation of Nitroarenes Catalyzed by CoCu Anchored on Nitrogen-doped Porous Carbon
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The non-precious metal catalysts with high catalytic activity is extremely desirable but still full of challenges. In this paper, CoCu bimetal immobilized on nitrogen-doped porous carbon (CoCu-N-C) was prepared by an effective ligand-stabilized pyrolysis strategy. CoCu-N-C exhibited excellent catalytic efficiency for the transfer hydrogenation of nitroarenes with ammonia borane as hydrogen source, which can be ascribed to the well dispersed metal nanoparticles, the synergetic interaction of CoCu bimetal and nitrogen-doped carbon. The durability and recyclability experiments of the recycled CoCu-N-C catalyst indicated that no obvious change in catalytic performance was observed after five consecutive cycles. To gain insight into the catalytic mechanism of CoCu-N-C for the hydrogenation reaction, density functional theory calculations was also conducted. This work provides an universal approach for constructing highly efficient non-precious metal heterogeneous catalysts and which may find diverse high performance applications.
- Liu, Xiaotong,Zhang, Longkang,Wang, Junmin,Shang, Ningzhao,Gao, Shutao,Wang, Chun,Gao, Yongjun
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- Preparation method of O-aminoacetophenone
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The invention discloses a preparation method of o-aminoacetophenone. The preparation method comprises the following steps: (1) mixing o-nitroethylbenzene, an oxidant, a cocatalyst and an organic solvent, heating the obtained mixed solution to a certain temperature for a reaction, and subjecting the reacted solution to cooling, quenching and extracting to obtain o-nitroacetophenone; and (2) addinga polar solvent and a metal catalyst into the obtained o-nitroacetophenone, carrying out a hydrogenation reduction reaction to obtain a crude o-aminoacetophenone product, and filtering and rectifyingthe crude o-aminoacetophenone product to obtain a refined o-aminoacetophenone product. According to the invention, used raw materials are low in price and easy to obtain, and steps are simple and easyto operate. The o-aminoacetophenone obtained by the method disclosed by the invention is high in purity and high in yield.
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Paragraph 0047; 0049; 0050; 0052; 0053; 0055; 0056; 0058
(2020/04/17)
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- Differences in the selective reduction mechanism of 4-nitroacetophenone catalysed by rutile- And anatase-supported ruthenium catalysts
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Ru/TiO2 catalysts exhibit excellent catalytic performance for selective reduction of 4-nitroacetophenone to 4-aminoacetophenone at normal temperature and atmospheric hydrogen pressure. Moreover, 99.9% selectivity to 4-aminoacetophenone can be obtained over 2.7 wt% Ru/TiO2(anatase) catalyst even in a relatively wide temperature (55-115 °C) and time (1-12 h) range. Its excellent catalytic performance is derived from the activation of H2 on the Ru nanoparticles at atmospheric pressure and the strong interaction of nitro groups with the support surface. Additionally, Ru nanoparticles supported on different crystalline TiO2 phases (anatase and rutile) result in different reaction pathways for 4-nitroacetophenone. Since the Ti-Ti distance on the rutile surface is smaller than that on the anatase surface, the hydroxylamine species adsorbed on the Ti atoms of rutile are more susceptible to the coupling reaction. Therefore, Ru/TiO2(rutile) causes a series of intermediates to accumulate during the conversion process, while Ru/TiO2(anatase) allows the highly selective conversion of 4-nitroacetophenone to 4-aminophenone. In addition, Ru/TiO2(anatase) can achieve chemoselective reduction of nitroaromatics to the corresponding anilines in the presence of -CN, -CHO, and -COOH, especially nitroaromatics containing CC and CC, indicating the excellent applicability.
- Gu, Xianmo,Pei, Linjuan,Wang, Jie,Zhang, Jin,Zheng, Zhanfeng,Zhu, Pengqi
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p. 1518 - 1528
(2020/03/26)
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- Highly efficient one-pot multi-directional selective hydrogenation and N-alkylation catalyzed by Ru/LDH under mild conditions
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Atomic economy, non-toxicity, harmlessness and multidirectional selectivity advocated by green chemistry have increasingly become a hot and difficult research topic. Herein, we present a highly efficient, one-pot tandem and easy-to-operate method through which we could directly produce a broad range of multi-directional selective hydrogenated amines or N-alkyl aliphatic amines using aromatic nitro compounds as raw materials. Ru/LDH with characteristics of layered mesoporous structure, well dispersed small Ru nanoparticles and LDH stabilization to the Ru NPs was employed as the catalyst. It is remarkable that multi-directional superb chemoselectivity to aromatic amines, alicyclic amines as well as N-alkyl aliphatic amines could be achieved with excellent catalytic activity and recyclability by tuning reaction conditions over 5wt%Ru/LDH-2. Additionally, this catalytic system also exhibited attractive activity and multi-directional chemoselectivity in the hydrogenation of quinoline and its derivatives with solvents of different polarity. Chemoselectivity to 5,6,7,8-tetrahydroquinoline derivatives could reach as high as 95.6 %.
- Zhang, Sishi,Xu, Jie,Cheng, Hongmei,Zang, Cuicui,Sun, Bin,Jiang, Heyan,Bian, Fengxia
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supporting information
(2020/03/30)
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- Modulating charge migration in photoredox organic transformationviaexquisite interface engineering
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Modulating photo-induced charge separation/transfer constitutes a central challenge in heterogeneous photocatalysis. Despite advancements in this area, finely tuning directional electron migration without involving conventional co-catalysts [e.g., metal nanocrystals and transition metal dichalcogenides (TMDs)] for boosted photoredox catalysis has not yet been explored. Herein, we report the exquisite design of a novel and general macromolecule-modulated photoredox selective organic transformation system, wherein an ultrathin macromolecular poly(diallyldimethylammonium chloride) (PDDA) layer was integrated at the interface of wide-band-gap (WBG) and narrow-band-gap (NBG) semiconductors to construct heterostructured photocatalysts. The ultra-thin PDDA interim layer expedites interfacial unidirectional electron transfer from the NBG to WBG semiconductor, resulting in a cascade electron transfer channel. The favorable energy level alignment among the building blocks, intimate interfacial integration and multilayered nanoarchitecture endow the WBG@PDDA@NBG heterostructures with substantially enhanced and versatile photoredox performance toward the selective oxidation of aromatic alcohols to aldehydes and the anaerobic reduction of nitroaromatics to amino compounds under visible light irradiation. This can be ascribed to the crucial role of the ultrathin intermediate PDDA layer as a highly efficient metal and TMD-free charge transfer mediator, relaying the electrons from the NBG to WBG semiconductor and slowing charge recombination. Our work could open up new frontiers to exploit diverse metal and TMD-free photocatalytic systems and provide a first insight into the fine tuning of charge transport utilizing non-conductive ionic polymers for solar energy conversion.
- Xu, Shuai,Huang, Ming-Hui,Li, Tao,Wei, Zhi-Quan,Lin, Xin,Dai, Xiao-Cheng,Hou, Shuo,Fu, Xiao-Yan,Xiao, Fang-Xing
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supporting information
p. 8360 - 8375
(2020/05/16)
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- Selective organic transformation over a self-assembled all-solid-state Z-scheme core-shell photoredox system
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Z-Scheme artificial photosystems, resembling the natural photosynthesis procedure, circumvent the disadvantage of a single-ingredient photosystem and hold fascinating prospects for solar energy conversion. Despite the advancements, bottom-up elaborate design of composite heterostructured Z-scheme photosystems by flexible interface engineering for photoredox organic transformation has been poorly investigated. We herein report the construction of a metal-based Z-scheme photoredox systemviaa progressive self-assembly strategy integrated with a facile photo-deposition. Tailor-made hierarchically branched ligand-capped Pd nanocrystals (NCs) sandwiched in-between a WO3nanorod (NR) core and CdS shell are harnessed as the charge transport modulator to regulate the interfacial oxidation-reduction kinetics for boosted Z-scheme photocatalysis. The intermediate Pd NCs as Schottky-type electron flow mediators considerably accelerate the unidirectional Z-scheme charge motion rate, endowing multilayered WO3?Pd?CdS core-shell heterostructures with significantly boosted net efficiency of photoactivities toward anaerobic selective nitroaromatic reduction to amino derivatives and aromatic alcohol oxidation to aldehydes under visible light illumination. The predominant active species produced in the versatile photocatalytic selective organic transformation were explored and photocatalytic mechanisms were thus ascertained. Our endeavor could offer a promising route for smartly crafting diverse heterostructured Z-scheme photoredox systems for solar energy conversion.
- Fu, Xiao-Yan,Hou, Shuo,Lin, Xin,Mo, Qiao-Ling,Wei, Zhi-Quan,Xiao, Fang-Xing,Xu, Shuai
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p. 20151 - 20161
(2020/10/18)
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- High-Density and Thermally Stable Palladium Single-Atom Catalysts for Chemoselective Hydrogenations
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Single-atom catalysts (SACs) have shown superior activity and/or selectivity for many energy- and environment-related reactions, but their stability at high site density and under reducing atmosphere remains unresolved. Herein, we elucidate the intrinsic driving force of a Pd single atom with high site density (up to 5 wt %) under reducing atmosphere, and its unique catalytic performance for hydrogenation reactions. In situ experiments and calculations reveal that Pd atoms tend to migrate into the surface vacancy-enriched MoC surface during the carburization process by transferring oxide crystals to carbide crystals, leading to the surface enrichment of atomic Pd instead of formation of particles. The Pd1/α-MoC catalyst exhibits high activity and excellent selectivity for liquid-phase hydrogenation of substituted nitroaromatics (>99 %) and gas-phase hydrogenation of CO2 to CO (>98 %). The Pd1/α-MoC catalyst could endure up to 400 °C without any observable aggregation of single atoms.
- Baaziz, Walid,Chu, Wei,Ersen, Ovidiu,Greiner, Mark,Liu, Wei,Liu, Yuefeng,Ma, Ying,Pham-Huu, Cuong,Ren, Yujing,Wang, Aiqin,Zhang, Tao,Zhou, Yanan
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supporting information
p. 21613 - 21619
(2020/09/21)
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- Experimental and Computational Studies on Cp*CyRh(III)/KOPiv-Catalyzed Intramolecular Dehydrogenative Cross-Couplings for Building Eight-Membered Sultam/Lactam Frameworks
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Described herein is an unusual Cp*CyRh(III)-catalyzed intramolecular site-specific aryl C-H annulation, a highly chemoselective protocol providing direct access to eight-membered sultams/lactams with broad substrate/functional group tolerance. Experimental and computational studies reveal that such a transformation involves a unique PivOH-assisted aryl C-H activation/alkene insertion/β-H elimination/hydrogen-transfer process involving the Rh(III)-hydride species as the active intermediate with the concomitant release of H2 as the major byproduct, thus enabling the developed Cp*CyRh(III) catalysis with redox-neutral and highly atom-economical features.
- Li, Liping,Gao, Hui,Sun, Ming,Zhou, Zhi,Yi, Wei
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supporting information
p. 5473 - 5478
(2020/07/14)
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- Superhydrophobic nickel/carbon core-shell nanocomposites for the hydrogen transfer reactions of nitrobenzene and N-heterocycles
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In this work, catalytic hydrogen transfer as an effective, green, convenient and economical strategy is for the first time used to synthesize anilines and N-heterocyclic aromatic compounds from nitrobenzene and N-heterocycles in one step. Nevertheless, how to effectively reduce the possible effects of water on the catalyst by removal of the by-product water, and to further introduce water as the solvent based on green chemistry are still challenges. Since the structures and properties of carbon nanocomposites are easily modified by controllable construction, a one step pyrolysis process is used for controllable construction of micro/nano hierarchical carbon nanocomposites with core-shell structures and magnetic separation performance. Using various characterization methods and model reactions the relationship between the structure of Ni?NCFs (nickel-nitrogen-doped carbon frameworks) and catalytic performance was investigated, and the results show that there is a positive correlation between the catalytic performance and hydrophobicity of catalysts. Besides, the possible catalytically active sites, which are formed by the interaction of pyridinic N and graphitic N in the structure of nitrogen-doped graphene with the surfaces of Ni nanoparticles, should be pivotal to achieving the relatively high catalytic performance of materials. Due to its unique structure, the obtained Ni?NCF-700 catalyst with superhydrophobicity shows extraordinary performances toward the hydrogen transfer reaction of nitrobenzene and N-heterocycles in the aqueous state; meanwhile, it was also found that Ni?NCF-700 still retained its excellent catalytic activity and structural integrity after three cycles. Compared with traditional catalytic systems, our catalytic systems offer a highly effective, green and economical alternative for nitrobenzene and N-heterocycle transformation, and may open up a new avenue for simple construction of structure and activity defined carbon nanocomposite heterogeneous catalysts with superhydrophobicity.
- Duan, Zhiying,Liu, Fangfang,Pang, Shaofeng,Su, Qiong,Wang, Yanbin,Xie, Xin,Zhang, Ping,Zhang, Yujing,Zhou, Feng
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p. 1996 - 2010
(2020/04/07)
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- Visible Light Induced Cyclization to Spirobi[indene] Skeletons from Functionalized Alkylidienecyclopropanes
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In this paper, we revealed a metal-free and visible light photoinduced method for the rapid construction of spirobi[indene] skeletons, providing a simple and efficient way for easy access to spirobi[indene] scaffolds under mild conditions along with a broad substrate scope and good functional group tolerance.
- Li, Quanzhe,Liu, Jiaxin,Shi, Min,Wei, Yin
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- Rapid construction of cyclopenta[: B] naphthalene frameworks from propargylic alcohol tethered methylenecyclopropanes
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We have developed a new synthetic methodology for the rapid construction of cyclopenta[b]naphthalene frameworks from the reaction of propargylic alcohol tethered methylenecyclopropanes with mesyl chloride in the presence of triethylamine through cascade cyclization. The reaction can be performed under mild conditions without the use of transition metals, affording the target products in moderate to good yields, and this cyclization reaction process can be scaled up to a gram-scale synthesis.
- Wei, Hao-Zhao,Li, Quan-Zhe,Wei, Yin,Shi, Min
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p. 7396 - 7400
(2020/10/13)
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- Novel 4-(1H-1,2,3-triazol-4-yl)methoxy)cinnolines as potent antibacterial agents: Synthesis and molecular docking study
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A new series of cinnoline-1,2,3-triazole derivatives were designed and synthesized by adopting Cu(1) catalyzed regeoselective1,3-dipolar cycloaddition reaction of terminal alkyne and azide. The in vitro antibacterial activity of all these compounds revealed that compounds 9d, 10a, 10b, and 10c are more potent antibacterial agents. Among the series, compound 4-(3-(4-((cinnolin-4-yloxy)methyl)-1H-1,2,3-triazol-1-yl)propyl)morpholine (10b) exhibited the most potent antibacterial activity against all tested gram-positive and gram-negative bacterial strains. Furthermore, molecular docking studies were also performed to understand the binding interactions of the most active analogs 9d, 10a, 10b, and 10c with Elastase of Pseudomonas aeruginosa (PDB: 1U4G). The results indicated that these classes of compounds have potential antibacterial activity, especially the compound 10b may serve as a promising antibacterial lead compound that could be further optimized for the further development of antibacterial drugs.
- Boda, Sathish Kumar,Bommagani, Mohan Babu,Chitneni, Prasad Rao,Mokenapelli, Sudhakar,Yerrabelli, Jayaprakash Rao
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- Redox-driven deracemization of secondary alcohols by sequential ether/O2-mediated oxidation and Ru-catalyzed asymmetric reduction
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The deracemization of benzylic alcohols has been achieved using a redox-driven one-pot two-step process. The racemic alcohols were oxidized by bis(methoxypropyl) ether and oxygen to give the ketone intermediates, followed by an asymmetric transfer hydrogenation with a chiral ruthenium catalyst. This compatible oxidation/reduction process gave the enantiomerically enriched alcohols with up to 95% ee values.
- Yang, Bing,Cui, Peng,Chen, Yongsheng,Liu, Qixing,Zhou, Haifeng
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supporting information
(2020/10/14)
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- One-Pot Synthesis of Spirocyclopenta[ a]indene Derivatives via a Cascade Ring Expansion and Intramolecular Friedel-Crafts-Type Cyclization
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A one-pot efficient synthetic approach for the rapid construction of spirocyclopenta[a]indene derivatives has been developed via an iodine-initiated cascade ring expansion and intramolecular Friedel-Crafts-type cyclization from propargyl alcohol-tethered alkylidenecyclobutanes under mild conditions with broad substrate scope. This cascade process can be elegantly conducted on a gram scale. A plausible reaction mechanism has been proposed on the basis of a series of deuterium labeling and control experiments.
- Li, Quanzhe,Liu, Jiaxin,Wei, Yin,Shi, Min
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supporting information
p. 2438 - 2455
(2020/01/31)
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- Metal-free chemoselective reduction of nitroaromatics to anilines via hydrogen transfer strategy
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A novel protocol for chemoselective reduction of aromatic nitro compounds to aromatic amines has been established. The metal-free reduction goes through a hydrogen transfer process. Various easily reducible functional groups can be well tolerated under the optimized reaction conditions.
- Shuai, Qi,Li, Jun,Zhao, Feng,Su, Weike,Deng, Guojun
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p. 965 - 975
(2019/04/13)
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- MODULATORS OF STIMULATOR OF INTERFERON GENES (STING)
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The present invention relates to compounds of formula (I) and salts, stereoisomers, tautomers or N-oxides thereof that are useful as modulators of STING (Stimulator of Interferon Genes). The present invention further relates to the compounds of formula (I) for use as a medicament and to a pharmaceutical composition comprising said compounds.
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Page/Page column 63
(2020/01/08)
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- Synthesis of Diiodinated All-Carbon 3,3′-Diphenyl-1,1′-spirobiindene Derivatives via Cascade Enyne Cyclization and Electrophilic Aromatic Substitution
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A synthetic method for the construction of diiodinated all-carbon spirobiindene derivatives has been developed from the reaction of propargyl alcohol-tethered alkylidenecyclopropanes with iodine. The reaction proceeded through an iodination-initiated cascade intramolecular enyne cyclization and electrophilic aromatic substitution reaction process in 1,2-dichloroethane upon heating, giving desired spirocyclic products in moderate to excellent yields. Further transformation of the obtained products has also been presented.
- Li, Quanzhe,Yu, Liuzhu,Wei, Yin,Shi, Min
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p. 9282 - 9296
(2019/08/12)
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- The Reaction of o-Aminoacetophenone N-Tosylhydrazone and CO2 toward 1,4-Dihydro-2H-3,1-benzoxazin-2-ones
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A transition-metal-free reaction of o-aminoacetophenone N-tosylhydrazone and CO2 has been developed, leading to a series of 1,4-dihydro-2H-3,1-benzoxazin-2-ones in moderate to good yields. This procedure proceeds with the sequential fixation of CO2 by amino leading to carbamic acid and the intra- molecular insertion of hydroxyl to carbene. (Figure presented.).
- Xiong, Hao,Wu, Xiaopeng,Wang, Hepan,Sun, Song,Yu, Jin-Tao,Cheng, Jiang
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supporting information
p. 3538 - 3542
(2019/07/10)
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- Weakly Coordinating, Ketone-Directed (η5-Pentamethylcyclopentadienyl)cobalt(III)- and (η5-Pentamethylcyclopentadienyl)rhodium(III)-Catalyzed C?H Amidation of Arenes: A Route to Acridone Alkaloids
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The weakly coordinating, ketone-directed, regioselective monoamidation of aromatic ketones, chalcone, carbazole, and benzophenones was achieved by employing high-valent cobalt and rhodium catalysis to access numerous biologically important molecular building blocks. This amidation proceeded smoothly with a variety of ketones and several amidating partners. The application of the products in the synthesis of various heterocycles, including acridones, indoles, quinoline, quinolones, quinolinones, and quinazolines, was also explored. The total synthesis of acridone-based alkaloids, namely, toddaliopsin A, toddaliopsin D, and arborinine, and the formal synthesis of acronycine and noracronycin were also accomplished by applying this method. A mechanistic study revealed this amidation reaction follows a base-assisted intermolecular electrophilic substitution pathway.
- Bera, Sourav Sekhar,Sk, Md Raja,Maji, Modhu Sudan
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supporting information
p. 1806 - 1811
(2019/01/14)
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- Method for synthesizing chiral alcohol through deracemization
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The invention relates to a method for synthesizing chiral alcohol (formula I) through deracemization. The preparation method provided by the invention is one-pot asymmetric cascade reaction, and comprises the following steps: 1), with racemic alcohol (formula II) as a raw material and dipropylene glycol dimethyl ether as a solvent, reacting at 120 DEG C for 12 hours, and performing a dehydrogenation reaction to produce intermediate ketone (formula III); and 2), directly adding 2.5mol% of a chiral diamine metal ruthenium complex as a catalyst into a reaction system, with 5 equivalents of sodiumformate as a hydrogen source and a mixed solution of methanol and water as a solvent, reacting at 50 DEG C for 12 hours under the protection of nitrogen, and performing asymmetric transfer hydrogenation to obtain the chiral alcohol (formula I). The method has the advantages of environment-friendly synthesis such as a simple and mild reaction condition, step economy and atomic economy; and in addition, a substrate has a wide application range, the enantioselectivity is high, and the method has a broad application prospect in synthesis of chiral alcohol pharmaceutical intermediates and fine chemical raw materials.
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Paragraph 0050-0052
(2019/07/29)
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- Copper-catalyzed tandem annulation/enol nucleophilic addition to access multisubstituted indoles
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A method to access various multisubstituted indoles from propargylic alcohols and readily available enol nucleophiles by copper-catalyzed tandem annulation/enol nucleophilic addition has been developed. Compared to the expensive metal catalysts such as platinum, gold, silver, and palladium used previously, the most economical copper(i) catalyst could achieve this reaction efficiently. The fused heterocyclic compounds, pyrrolo[1,2-a] indoles, could be afforded by further transformation of the products. The allyl cation intermediate may be involved in the mechanism.
- Song, Wangze,Li, Ming,He, Junnan,Li, Junhao,Dong, Kun,Zheng, Yubin
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supporting information
p. 2663 - 2669
(2019/03/13)
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- Gold-catalyzed cyclization of 1-(2′-Azidoaryl) propynols: Synthesis of polysubstituted 4-quinolones
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An unprecedented gold-catalyzed procedure for the synthesis of polysubstituted 4-quinolones from 1-(2′-Azidoaryl) propynols is described. The reaction undergoes an intramolecular nucleophilic attack of the azide group to the Au-Activated triple bonds in a 6-endo-dig manner and subsequent gold-Assisted expulsion of N2 to furnish an α-imino gold carbene intermediate, which triggers a 1,2-carbon migration and finally is converted to 2,3-disubstituted 4-quinolone.
- Wu, Xiang,Zheng, Lang-Lang,Zhao, Li-Ping,Zhu, Cheng-Feng,Li, You-Gui
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supporting information
p. 14769 - 14772
(2019/12/24)
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- 3 - Methyl - 1 H - indazole synthesis process
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The invention relates to a synthesizing process of 3-methyl-1 H-indazole. The synthesizing process comprises the following steps: acetophenone is dropped into a sulfuric acid and nitric acid mixture solution, then calcium metasilicate powder is added, the mixture is kept to be stirred at lower temperature and passes through the night, the mixture is added into ice water and filtered, and 2-nitroacetophenone is obtained; the 2-nitroacetophenone, iron powder and ammonium chloride are synthesized into white solid 2-aminoacetophenone; the 2-aminoacetophenone is added to hydrochloric acid, then an NaNO2 aqueous solution is added, the mixture is stirred, then a hydrochloric acid solution of SnCl2.H2O is added, the mixture is stirred, the mixture is added to ice water and filtered, and filtrate is adjusted to alkalescence, filtered and dried so that the 3-methyl-1 H-indazole is obtained. According to the synthesizing process of the 3-methyl-1 H-indazole, calcium silicate is taken as a catalyst, the yield of the 2-nitroacetophenone is increased remarkably, the raw material of calcium silicate is easy to obtain, the cost is low, the operation and the use are simple, later synthesis of 2-aminoacetophenone and the 3-methyl-1 H-indazole is further facilitated, and the synthesizing process is suitable for industrial large-scale synthesis of 3-methyl-1 H-indazole.
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- 2-aryl-2,3-dihydro-4(1H)-quinolinone semicarbazone compound and application thereof
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The invention relates to the field of medicine technology, and a series of novel 2-aryl-2,3-dihydrogen-4(1H)-quinolinone semicarbazone derivatives (I) and pharmaceutically acceptable salts, solvates,optical isomers or polymorphs are designed and synthesized. The derivative (I) and its pharmaceutically acceptable salt, solvate, optical isomer or polymorph can be mixed as an active ingredient witha pharmaceutically acceptable carrier to prepare a pharmaceutical composition. A double dilution method is used for test of the antifungal activity of the derivative (I) and its pharmaceutically acceptable salt, solvate, optical isomer or polymorph, and the results show that the derivative has stronger killing effect on clinically common pathogenic fungi, and is expected to overcome the defects oflarge toxic and side effects, easy generation of drug resistance of azole antifungal medicines which are widely used clinically. The specific formula is shown in the description.
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Paragraph 0054; 0055; 0056
(2018/10/19)
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- Chemoselective hydrogenation of nitroarenes catalyzed by cellulose-supported Pd NPs
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Cellulose-supported palladium nanoparticles (NPs) were prepared by straightforward deposition of metal NPs on modified cellulose. The catalyst exhibited excellent catalytic activity and selectivity in room-temperature hydrogenation of various nitroarenes to arylamines under atmospheric hydrogen pressure in neat water without any additives. High chemoselectivity was also achieved in the hydrogenation of substituted nitroarenes with multiple reducible groups. The catalyst can be recycled by simple centrifugation and reused for at least 4 times without significant decline of yields.
- Li, Dan-dan,Zhang, Jia-wei,Cai, Chun
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- Nitro group reduction and Suzuki reaction catalysed by palladium supported on magnetic nanoparticles modified with carbon quantum dots generated from glycerol and urea
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Glycerol and urea were used as green and cheap sources of carbon quantum dots (CQD) for modifying Fe3O4 nanoparticles (NPs). The obtained CQD@Fe3O4 NPs were used for the stabilization of palladium species and the prepared catalyst, Pd@CQD@Fe3O4, was characterized using various techniques. This magnetic supported palladium was applied as an efficient catalyst for the reduction of aromatic nitro compounds to primary amines at room temperature using very low palladium loading (0.008?mol%) and also for the Suzuki–Miyaura cross-coupling reaction of aryl halides as well as challenging heteroaryl bromides and aryl diazonium salts with arylboronic acids and with potassium phenyltrifluoroborate. This magnetically recyclable catalyst was recovered and reused for seven consecutive runs in the reduction of 4-nitrotoluene to p-toluidine and for ten consecutive runs in the reaction of 4-iodoanisole with phenylboronic acid with small decrease of activity. The catalyst reused in the Suzuki reaction was characterized using transmission electron microscopy, vibrating sample magnetometry and X-ray photoelectron spectroscopy. Using experiments such as hot filtration and poisoning tests, it has been shown that the true catalyst works under homogeneous conditions according to the release–return pathway of active palladium species.
- Gholinejad, Mohammad,Zareh, Fatemeh,Nájera, Carmen
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- Pd supported on g-C3N4 nanosheets: Mott-Schottky heterojunction catalyst for transfer hydrogenation of nitroarenes using formic acid as hydrogen source
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Well-dispersed Pd nanoparticles were anchored on g-C3N4 nanosheets, which were prepared by a liquid-phase exfoliation method. The hybrid material displayed excellent catalytic activity for the transfer hydrogenation of nitroarenes. The reactions can be conducted smoothly in water at room temperature with formic acid as hydrogen source. Aniline was produced in excellent yield (>99%; turnover frequency: 853), surpassing the majority of reported heterogeneous catalysts using formic acid or formates as hydrogen source. The increased activity of such a hybrid catalyst can be ascribed to the nitrogen-rich and amphipathic property of the carbon nitride support, the stable and uniform dispersed Pd nanoparticles and the Mott-Schottky effect between the g-C3N4 nanosheets and the metal nanoparticles. The heterogeneous Mott-Schottky catalyst can be reused for five cycles without any obvious loss of its catalytic activity.
- Cheng, Saisai,Meng, Xufeng,Shang, Ningzhao,Gao, Shutao,Feng, Cheng,Wang, Chun,Wang, Zhi
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p. 1771 - 1778
(2018/02/09)
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- Domino Aryne Annulation via a Nucleophilic-Ene Process
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1,2-Benzdiyne equivalents possess the unique property that they can react with two arynophiles through iteratively generated 1,2- and 2,3-aryne intermediates. Upon rational modification on the second leaving group of these aryne precursors, a domino aryne annulation approach was developed through a nucleophilic-ene reaction sequence. Various benzo-fused N-heterocyclic frameworks were achievable under transition metal-free conditions with a broad substrate scope.
- Xu, Hai,He, Jia,Shi, Jiarong,Tan, Liang,Qiu, Dachuan,Luo, Xiaohua,Li, Yang
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supporting information
p. 3555 - 3559
(2018/03/21)
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- Highly efficient aqueous phase reduction of nitroarenes catalyzed by phosphine-decorated polymer immobilized ionic liquid stabilized PdNPs
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Palladium nanoparticles stabilized by lightly cross-linked phosphine-decorated polymer immobilized ionic liquids (PIIL) and their PEGylated counterparts (PEGPIIL) are highly effective catalysts for the aqueous phase hydrogenation and sodium borohydride-based reduction of a wide range of nitroaromatic and heteroaromatic compounds under mild conditions with low catalyst loadings. Introduction of extensive cross-linking with tris(4-vinylphenyl)phosphine to isolate the phosphine-based heteroatom and limit the number of surface Pd?P interactions did not have a significant influence on catalyst performance. Comparative testing revealed PdNPs immobilized on lightly cross-linked phsophine-decoarted PEGylated polymer to be a highly efficient catalyst for the aqueous phase reduction of nitroarenes with a TON of 36000 (TOF = 2580 h-1) for hydrogenation and a TON of 274000 (TOF = 17125 h-1) for transfer hydrogenation. Even though these reactions occur under diffusion control due the poor solubility of the substrate these values are the highest to be reported for the room temperature aqueous phase reduction of nitroarenes catalyzed by a nanoparticle-based system. A continuous flow reduction of nitrobenzene in a packed bed reactor operated over a period of 250 min with no sign of catalyst deactivation and the corresponding space-time-yield of 0.738 g L-1 min-1 is a marked improvement on that of 0.384 g L-1 min-1 obtained in batch. The same system also catalyzes a tandem Suzuki-Miyaura cross coupling-nitroarene reduction sequence to afford high yields of biaryl amine in an operationally straightforward single-pot procedure. This is a highly versatile protocol which will enable the aromatic nitro fragment to be introduced as a nitro-substituted aryl or heteroaryl halide and as such will lend itself to rapid diversification for the synthesis of a wide range of amines.
- Doherty,Knight,Backhouse,Bradford,Saunders,Bourne,Chamberlain,Stones,Clayton,Lovelock
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p. 1454 - 1467
(2018/03/13)
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- Molybdenum-Catalyzed Sustainable Friedl?nder Synthesis of Quinolines
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Polysubstituted quinolines have been efficiently synthesized from nitroarenes and glycols, as reducing agents, under dioxomolybdenum(VI)-catalysis. Interestingly, the waste reduction byproduct is incorporated into the final heterocycle. This method repres
- Rubio-Presa, Rubén,Suárez-Pantiga, Samuel,Pedrosa, María R.,Sanz, Roberto
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supporting information
p. 2216 - 2220
(2018/06/14)
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- Water-Soluble Hypervalent Iodine(III) Having an I-N Bond. A Reagent for the Synthesis of Indoles
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A readily accessible and bench-stable water-soluble hypervalent iodine(III) reagent (phenyliodonio)sulfamate (PISA) with an I-N bond was synthesized, and its structure was characterized by X-ray crystallography. With PISA, various indoles were synthesized via C-H amination of 2-alkenylanilines involving an aryl migration/intramolecular cyclization cascade with excellent regioselectivity in aqueous CH3CN. Notably, using this new method as the key step, not only two drug molecules, indometacin and zidometacin, but also another bioactive molecule, pravadoline, were synthesized.
- Xia, Hai-Dong,Zhang, Yan-Dong,Wang, Yan-Hui,Zhang, Chi
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supporting information
p. 4052 - 4056
(2018/07/15)
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- Indium-Catalyzed Annulation of o-Acylanilines with Alkoxyheteroarenes: Synthesis of Heteroaryl[b]quinolines and Subsequent Transformation to Cryptolepine Derivatives
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We disclose herein the first synthetic method that is capable of offering heteroaryl[b]quinolines (HA[b]Qs) with structural diversity, which include tricyclic and tetracyclic structures with (benzo)thienyl, (benzo)furanyl, and indolyl rings. The target HA[b]Q is addressed by the annulation of o-acylanilines and MeO-heteroarenes with the aid of an indium Lewis acid that effectively works to make two different types of the N-C and C-C bonds in one batch. A series of indolo[3, 2-b]quinolines prepared here can be subsequently transformed to structurally unprecedented cryptolepine derivatives. Mechanistic studies showed that the N-C bond formation is followed by the C-C bond formation. The indium-catalyzed annulation reaction thus starts with the nucleophilic attack of the NH2 group of o-acylanilines to the MeO-connected carbon atom of the heteroaryl ring in an SNAr fashion, and thereby the N-C bond is formed. The resulting intermediate then cyclizes to make the C-C bond through the nucleophilic attack of the heteroaryl-ring-based carbon atom to the carbonyl carbon atom, providing the HA[b]Q after aromatizing dehydration.
- Yonekura, Kyohei,Shinoda, Mika,Yonekura, Yuko,Tsuchimoto, Teruhisa
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