- Selective synthesis of Rh5 carbonyl clusters within a polyamine dendrimer for chemoselective reduction of nitro aromatics
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The selective synthesis of the [Rh5(CO)15] - cluster within the PPI dendrimer was successfully demonstrated. The dendrimer-encapsulated [Rh5(CO)15]- was resistant to decomposition under the catalytic reaction conditions and exhibited extremely high selectivity for the chemoselective reduction of nitro groups of various nitro aromatics with other reducible groups using CO/H2O as a reductant. This journal is the Partner Organisations 2014.
- Maeno, Zen,Mitsudome, Takato,Mizugaki, Tomoo,Jitsukawa, Koichiro,Kaneda, Kiyotomi
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- In situ mosaic strategy generated Co-based N-doped mesoporous carbon for highly selective hydrogenation of nitroaromatics
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The development of heterogeneous non-noble metal catalytic architectures that can realize the high selective and stable hydrogenation of nitroaromatics under mild conditions is a profound challenge in the catalysis community. Here we report a facile synthesis of highly nitrogen doped and uniformly embedded Co-based mesoporous carbon catalyst through a thermolysis and etching combined strategy, in which the commercial cobalt phthalocyanine and colloidal silica serve as precursor and hard template, respectively. The protocol allows for simultaneous optimization of porous features and cobalt nanoparticles of N-doped mesoporous carbon catalyst by fine-tuning thermolysis temperature. Among the as-prepared catalysts, Co@NMC-800 with lower dosage of cobalt exhibits outstanding catalytic activity and chemoselectivity for various nitroaromatics under mild condition (2.0?mol% Co, 1.0?MPa H2, 80?°C, xand Co NPs surface wrapped thin carbon layers plays a crucial role in providing the excellent selectivity for hydrogenation of vulnerable nitroaromatics via preferential adsorption of polar nitro group.
- Li, Huan,Yang, Hengquan,Zhang, Fengwei,Zhang, Xian-Ming,Zhao, Chao,Chen, Shuai
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- Nickel Boride Reduction of Aryl Nitro Compounds
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Nickel boride smoothly reduces aryl nitro compounds to the corresponding anilines in the presence of iodo and ortho carboalkoxy groups in contrast to the problematic reductions by other methods.
- Seltzman, Herbert H.,Berrang, Bertold D.
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- Characterization of different commercial soybean peroxidase preparations and use of the enzyme for N-demethylation of methyl N-methylanthranilate to produce the food flavor methylanthranilate
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The potential of different peroxidase preparations for the N- demethylation of methyl N-methylanthranilate to produce the food flavor methylanthranilate (MA) was investigated. All tested peroxidase preparations were able to catalyze the N-dealkylation. The tested soybean preparations vary widely with respect to their heme content. Furthermore, the operational stability of purified soybean peroxidase (SP) is at least 25-fold lower than that of horseradish peroxidase and only 5-fold higher than that of microperoxidase 8. Thus, the presence of a large protein chain around a porphyrin cofactor in a peroxidase is, by itself, insufficient to explain the observed differences in operational stability. Despite its relatively low operational stability, SP proved to be the most efficient biocatalyst for the production of MA with high yield and purity, especially observed at the high temperature and low pH values at which SP appeared to be optimally active.
- Van Haandel, Marjon J. H.,Saraber, Florence C. E.,Boersma, Marelle G.,Laane, Colja,Fleming, Yvette,Weenen, Hugo,Rietjens, Ivonne M. C. M.
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- Competitive homolytic and heterolytic decomposition pathways of gas-phase negative ions generated from aminobenzoate esters
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An alkyl-radical loss and an alkene loss are two competitive fragmentation pathways that deprotonated aminobenzoate esters undergo upon activation under mass spectrometric conditions. For the meta and para isomers, the alkyl-radical loss by a homolytic cleavage of the alkyl-oxygen bond of the ester moiety is the predominant fragmentation pathway, while the contribution from the alkene elimination by a heterolytic pathway is less significant. In contrast, owing to a pronounced charge-mediated ortho effect, the alkene loss becomes the predominant pathway for the ortho isomers of ethyl and higher esters. Results from isotope-labeled compounds confirmed that the alkene loss proceeds by a specific γ-hydrogen transfer mechanism that resembles the McLafferty rearrangement for radical cations. Even for the para compounds, if the alkoxide moiety bears structural motifs required for the elimination of a more stable alkene molecule, the heterolytic pathway becomes the predominant pathway. For example, in the spectrum of deprotonated 2-phenylethyl 4-aminobenzoate, m/z 136 peak is the base peak because the alkene eliminated is styrene. Owing to the fact that all deprotonated aminobenzoate esters, irrespective of the size of the alkoxy group, upon activation fragment to form an m/z 135 ion, aminobenzoate esters in mixtures can be quantified by precursor ion discovery mass spectrometric experiments.
- Xia, Hanxue,Zhang, Yong,Pavlov, Julius,Jariwala, Freneil B.,Attygalle, Athula B.
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- Novel VEGFR-2 inhibitors with an N-acylhydrazone scaffold
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Vascular endothelial growth factor receptor 2 (VEGFR-2) is a tyrosine kinase that mediates a large number of cell responses associated with angiogenesis. The control of the angiogenic pathway in tumorigenesis by the inhibition of VEGFR-2 is considered a p
- Pauli, Fernanda P.,Martins, Juliana R.,Paschoalin, Thaysa,Ionta, Marisa,Barbosa, Maria Leticia C.,Barreiro, Eliezer J.
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- An ecofriendly catalytic route for the preparation of perfumery grade methyl anthranilate from anthranilic acid and methanol
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Methyl anthranilate is a very important perfumery ester and also a precursor to a number of Schiff bases which are used in several fragrance formulations. The current practice is to use homogeneous acids as catalysts in the manufacture of methyl anthranil
- Yadav,Krishnan
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- Reductive carbodiazenylation of nonactivated olefins via aryl diazonium salts
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The reduction of aryl diazonium salts in the presence of nonactivated olefins provides rapid entry to carbodiazenylation products. The regioselective functionalization of double bonds is achieved in a one-pot process starting from aniline derivatives. Car
- Heinrich, Markus R.,Blank, Olga,Woelfel, Sabrina
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- Self-Template Construction of High-Performance Co, N-Decorated Carbon Nanotubes from a Novel Cobalt Dicyandiamide Molecule
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N-doped carbon nanotubes (NCNTs) based composites have shown great prospect in catalysis relevant communities, which are often evolved from commercial CNTs and nitrogenous hybrid precursors. However, the direct fabrication of high-performance and non-nobl
- Li, Jingjing,Chen, Shuai,Liu, Mengmeng,Li, Zhihong,Dong, Zhengping,Zhang, Fengwei,Zhang, Xian-Ming
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- A facile reduction of aromatic nitro compounds to aromatic amines by samarium and iodine
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A simple method for the reduction of aromatic nitro compounds to aromatic amines was developed using samarium and catalytic amounts of iodine.
- Banik, Bimal K.,Mukhopadhyay, Chhanda,Venkatraman,Becker, Frederick F.
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- N-Doped Hierarchical Porous Carbon Embedded Synergistic Bimetallic CoCu NPs with Unparalleled Catalytic Performance
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By virtue of the structural diversity, electronic tunability and synergetic effect, heterogeneous non-noble bimetallic catalysts have demonstrated excellent catalytic performance in Fischer-Tropsch synthesis, biomass conversion and fine chemicals synthesi
- Zhang, Fengwei,Li, Zhihong,Ma, Chunlan,Han, Xu,Dong, Xue,Dong, Zhengping,Zhang, Xian-Ming
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- ALKYL AND ARYL ISOTHIOCYANATES AS MASKED PRIMARY AMINES
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Primary and secondary (but not tertiary) alkyl as well as aryl isothiocyanates react rapidly with 4-methyl-1,2-benzenedithiol (1) in methanol at room temperature, releasing the corresponding amines in good yields.This mild and simple procedure for unmasking amines proceeds chemospecifically with isothiocyanates even in the presence of such normally electrophilic and reactive functionalities as carboxylate ester and N-alkylphthalimide.
- Cho, Cheon-Gyu,Posner, Gary H.
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- High-affinity recognition of the human C-reactive protein independent of phosphocholine
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A high-affinity polypeptide conjugate 4-C25L22-DQ, has been developed for the molecular recognition of the human C-reactive protein, CRP, a well-known inflammation biomarker. CRP is one of the most frequently quantified targets in diagnostic applications and a target in drug development. With the exception of antibodies, most molecular constructs take advantage of the known affinity for CRP of phosphocholine that depends on Ca2+ for its ability to bind. 4-C25L22-DQ which is unrelated to phosphocholine binds in the absence of Ca2+ with a dissociation constant of 760 nM, an order of magnitude lower than that of phosphocholine, the KD of which is 5 μM. The small organic molecule 2-oxo-1,2-dihydroquinoline-8-carboxylic acid (DQ) was designed based on the structural similarities between three hits from a set of compounds selected from a building block collection and evaluated with regards to affinity for CRP by NMR spectroscopy. 4-C25L22-DQ was shown in a competition experiment to bind CRP three orders of magnitude more strongly than DQ itself, and in a pull-down experiment 4-C25L22-DQ was shown to extract CRP from human serum. The development of a robust and phosphocholine-independent recognition element provides unprecedented opportunities in bioanalytical applications in vivo and in vitro under conditions where the concentration of Ca2+ ions is low, or where Ca2+ binding agents such as EDTA or heparin are needed to prevent blood coagulation. The identification from a compound library of a small organic molecule and its conjugation to a small set of polypeptides, none of which were previously known to bind CRP, illustrates a convenient and general route to selective high-affinity binders for proteins with dissociation constants in the μM to nM range for which no small molecule ligands are known.
- Yang, Jie,Gustavsson, Anna-Lena,Haraldsson, Martin,Karlsson, G?ran,Norberg, Thomas,Baltzer, Lars
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- Production of natural methyl anthranilate by microbial N-demethylation of N-methyl methyl anthranilate by the topsoil-isolated bacterium Bacillus megaterium
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Bacillus megaterium, isolated in a screening process from topsoil, was used for N-demethylation of natural N-methyl methyl anthranilate to produce natural methyl anthranilate. Maximal productivity of 70 mg/L/day was achieved under laboratory-scale conditions without further optimization. No byproducts were observed. Thus, production of natural methyl anthranilate using B. megaterium is a significant improvement over comparable already existing procedures.
- Taupp, Marcus,Harmsen, Dag,Heckel, Frank,Schreier, Peter
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- Novel applications of ethyl glyoxalate with the Ugi MCR
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This letter describes novel high-yielding solution phase preparations of 1,4-benzodiazepine-2,5-dione, diketopiperazine, ketopiperazine and dihydroquinoxalinone libraries via a UDC (Ugi/de-Boc/cyclization) strategy in combination with ethylglyoxalate. The
- Hulme, Christopher,Cherrier
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- Structural elucidation of thermolysis products of methyl N-methyl-N-nitrosoanthranilate
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Although it is common knowledge that N-nitroso compounds are thermally (and otherwise chemically) labile, little or nothing is known about the specific reactions that occur during thermal treatment of a compound possessing this functionality. Methyl N-met
- Miltojevi?, Ana B.,Radulovi?, Niko S.
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- Tunable Electrosynthesis of Anthranilic Acid Derivatives via a C-C Bond Cleavage of Isatins
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A facile and direct electrocatalytic C-C bond cleavage/functionalization reaction of isatins was developed. With isatins as the amino-attached C1 sources, a variety of aminobenzoates, and aminobenzamides were synthesized in moderate to good yields under mild conditions.
- Qian, Peng,Liu, Jiaojiao,Zhang, Yan,Wang, Zhiyong
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p. 16008 - 16015
(2021/07/31)
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- Development of phenyltriazole thiol-based derivatives as highly potent inhibitors of DCN1-UBC12 interaction
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Defective in cullin neddylation 1(DCN1) is a co-E3 ligase that is important for cullin neddylation. Dysregulation of DCN1 highly correlates with the development of various cancers. Herein, from the initial high-throughput screening, a novel hit compound 5a containing a phenyltriazole thiol core (IC50 value of 0.95 μM for DCN1-UBC12 interaction) was discovered. Further structure-based optimization leads to the development of SK-464 (IC50 value of 26 nM). We found that SK-464 not only directly bound to DCN1 in vitro, but also engaged cellular DCN1, suppressed the neddylation of cullin3, and hindered the migration and invasion of two DCN1-overexpressed squamous carcinoma cell lines (KYSE70 and H2170). These findings indicate that SK-464 may be a novel lead compound targeting DCN1-UBC12 interaction.
- Zhou, Wenjuan,Xu, Chenhao,Dong, Guanjun,Qiao, Hui,Yang, Jing,Liu, Hongmin,Ding, Lina,Sun, Kai,Zhao, Wen
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- Ni2P Nanoalloy as an Air-Stable and Versatile Hydrogenation Catalyst in Water: P-Alloying Strategy for Designing Smart Catalysts
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Non-noble metal-based hydrogenation catalysts have limited practical applications because they exhibit low activity, require harsh reaction conditions, and are unstable in air. To overcome these limitations, herein we propose the alloying of non-noble metal nanoparticles with phosphorus as a promising strategy for developing smart catalysts that exhibit both excellent activity and air stability. We synthesized a novel nickel phosphide nanoalloy (nano-Ni2P) with coordinatively unsaturated Ni active sites. Unlike conventional air-unstable non-noble metal catalysts, nano-Ni2P retained its metallic nature in air, and exhibited a high activity for the hydrogenation of various substrates with polar functional groups, such as aldehydes, ketones, nitriles, and nitroarenes to the desired products in excellent yields in water. Furthermore, the used nano-Ni2P catalyst was easy to handle in air and could be reused without pretreatment, providing a simple and clean catalyst system for general hydrogenation reactions.
- Fujita, Shu,Yamaguchi, Sho,Yamasaki, Jun,Nakajima, Kiyotaka,Yamazoe, Seiji,Mizugaki, Tomoo,Mitsudome, Takato
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supporting information
p. 4439 - 4446
(2021/02/09)
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- Development and Application of Efficient Ag-based Hydrogenation Catalysts Prepared from Rice Husk Waste
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The development of strategies for the sustainable management and valorization of agricultural waste is of outmost importance. With this in mind, we report the use of rice husk (RH) as feedstock for the preparation of heterogeneous catalysts for hydrogenation reactions. The catalysts were prepared by impregnating the milled RH with a silver nitrate solution followed by carbothermal reduction. The composition and morphology of the prepared catalysts were fully assessed by IR, AAS, ICP-MS, XPS, XRD and STEM techniques. This novel bio-genic silver-based catalysts showed excellent activity and remarkable selectivity in the hydrogenation of nitro groups in both aromatic and aliphatic substrates, even in the presence of reactive functionalities like halogens, carbonyls, borate esters or nitriles. Recycling experiments showed that the catalysts can be easily recovered and reused multiple times without significant drop in performance and without requiring re-activation.
- Unglaube, Felix,Kreyenschulte, Carsten Robert,Mejía, Esteban
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p. 2583 - 2591
(2021/04/09)
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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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- A mild and selective Cu(II) salts-catalyzed reduction of nitro, azo, azoxy, N-aryl hydroxylamine, nitroso, acid halide, ester, and azide compounds using hydrogen surrogacy of sodium borohydride
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The first mild, in situ, single-pot, high-yielding well-screened copper (II) salt-based catalyst system utilizing the hydrogen surrogacy of sodium borohydride for selective hydrogenation of a broad range of nitro substrates into the corresponding amine under habitancy of water or methanol like green solvents have been described. Moreover, this catalytic system can also activate various functional groups for hydride reduction within prompted time, with low catalyst-loading, without any requirement of high pressure or molecular hydrogen supply. Notably, this system explores a great potential to substitute expensive traditional hydrogenation methodologies and thus offers a greener and simple hydrogenative strategy in the field of organic synthesis.
- Kalola, Anirudhdha G.,Prasad, Pratibha,Mokariya, Jaydeep A.,Patel, Manish P.
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supporting information
p. 3565 - 3589
(2021/10/12)
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- A Metal-Free Direct Arene C?H Amination
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The synthesis of aryl amines via the formation of a C?N bond is an essential tool for the preparation of functional materials, active pharmaceutical ingredients and bioactive products. Usually, this chemical connection is only possible by transition metal-catalyzed reactions, photochemistry or electrochemistry. Here, we report a metal-free arene C?H amination using hydroxylamine derivatives under benign conditions. A charge transfer interaction between the aminating reagents TsONHR and the arene substrates enables the chemoselective amination of the arene, even in the presence of various functional groups. Oxygen was crucial for an effective conversion and its accelerating role for the electron transfer step was proven experimentally. In addition, this was rationalized by a theoretical study which indicated the involvement of a dioxygen-bridged complex with a “Sandwich-like” arrangement of the aromatic starting materials and the aminating agents at the dioxygen molecule. (Figure presented.).
- Wang, Tao,Hoffmann, Marvin,Dreuw, Andreas,Hasagi?, Edina,Hu, Chao,Stein, Philipp M.,Witzel, Sina,Shi, Hongwei,Yang, Yangyang,Rudolph, Matthias,Stuck, Fabian,Rominger, Frank,Kerscher, Marion,Comba, Peter,Hashmi, A. Stephen K.
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supporting information
p. 2783 - 2795
(2021/04/05)
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- Minimization of Back-Electron Transfer Enables the Elusive sp3 C?H Functionalization of Secondary Anilines
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Anilines are some of the most used class of substrates for application in photoinduced electron transfer. N,N-Dialkyl-derivatives enable radical generation α to the N-atom by oxidation followed by deprotonation. This approach is however elusive to monosubstituted anilines owing to fast back-electron transfer (BET). Here we demonstrate that BET can be minimised by using photoredox catalysis in the presence of an exogenous alkylamine. This approach synergistically aids aniline SET oxidation and then accelerates the following deprotonation. In this way, the generation of α-anilinoalkyl radicals is now possible and these species can be used in a general sense to achieve divergent sp3 C?H functionalization.
- Zhao, Huaibo,Leonori, Daniele
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supporting information
p. 7669 - 7674
(2021/03/08)
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- Scaffold Hopping of Natural Product Evodiamine: Discovery of a Novel Antitumor Scaffold with Excellent Potency against Colon Cancer
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Inspired by the natural product evodiamine, a novel antitumor indolopyrazinoquinazolinone scaffold was designed by scaffold hopping. Structure-activity relationship studies led to the discovery of compound 15j, which shows low nanomolar inhibitory activity against the HCT116 cell line. Further antitumor mechanism studies indicated that compound 15j acted by the dual inhibition of topoisomerase 1 and tubulin and induced apoptosis with G2 cell-cycle arrest. The quaternary ammonium salt of compound 15j (compound 15js) exhibited excellent in vivo antitumor activity (TGI = 66.6%) in the HCT116 xenograft model with low toxicity. Indolopyrazinoquinazolinone derivatives represent promising multitargeting antitumor leads for the development of novel antitumor agents.
- Wang, Lei,Fang, Kun,Cheng, Junfei,Li, Yu,Huang, Yahui,Chen, Shuqiang,Dong, Guoqiang,Wu, Shanchao,Sheng, Chunquan
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p. 696 - 713
(2020/02/04)
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- Method for reducing aromatic nitro into arylamine
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The invention relates to a method for reducing aromatic nitro to arylamine. The method comprises the following steps: (1) taking an aromatic nitro compound as a raw material, water as a hydrogen source, a palladium compound, cheap and easy to obtain, as a catalyst and tetrahydroxydiboron as an additive to reduce nitro to obtain a product; (2) taking the aromatic nitro compound as the raw material, a copper salt, cheap and easy to obtain, as the catalyst, the tetrahydroxydiboron as the additive to reduce the nitro to obtain a product; and (3) taking the aromatic nitro compound as the raw material, water as the hydrogen source, and the tetrahydroxydiboron as the additive, without needing a metal catalyst, to reduce the nitro to obtain a product. A preparation method for the arylamine, which is provided by the invention, is mild in reaction condition, low in costs, environment-friendly, high in yield, and suitable for industrial production.
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Paragraph 0149-0152
(2020/07/15)
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- Method for preparing 2-amino-3-methyl nitrobenzoate
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The invention discloses a method for preparing methyl 2-amino-3-nitrobenzoate, which comprises the following steps: pumping a phthalimide solution and a sodium hypochlorite solution into a micro-reaction mixer, reacting, reacting with water in a tubular reactor to obtain methyl anthranilate, and continuously separating to obtain a crude product; pumping the methyl anthranilate crude product, an acetic anhydride solution and fuming nitric acid into a micro-channel reactor, mixing, reacting to obtain N-methyl nitrobenzoate, and continuously separating to obtain a crude product; pumping an N-methyl nitrobenzoate solution, concentrated sulfuric acid and water into a micro-channel reactor, mixing, and reacting to obtain a 2-amino-3-methyl nitrobenzoate crude product; recrystallizing the crude product in methanol to obtain a product, namely methyl 2-amino-3-nitrobenzoate; and the method is high in yield, good in safety and suitable for industrial production.
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Paragraph 0053-0055; 0059-0060; 0064-0065; 0069-0070; 0073
(2020/06/30)
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- Pd(OAc)2-catalyzed one-pot preparation of anthranilates from acyclic unsaturated β-enamino esters
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A one-pot synthesis of anthranilates from acyclic unsaturated β-enamino esters with a catalytic amount of Pd(OAc)2 was achieved for the first time. The substrates for the key catalytic reaction were easily prepared from acetoacetate esters and amines, and functionalized anthranilates were obtained in moderate to good chemical yields. A simple assembly of a 13C-labeled anthranilate was demonstrated by applying this protocol. In addition, bioactive NNI-5 was synthesized using this catalytic process.
- Kishimoto, Ryo,Mikami, Shunya,Okada, Sho,Takabatake, Tetsuhiko,Toyota, Masahiro
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- Synthesis of 3-phenylbenzo[c]isoxazoles by thermocyclization of 2-azidobenzophenones
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3-Phenylbenzo[c]isoxazoles were synthesized by non-catalytic thermolysis of 2-azidobenzophenones in dry xylene with quantitative yields. The trace content of water in solvents reduces the yields of the reaction products. 2-Azidobenzoic acid esters are sta
- Odinokov,Plekhovich,Budruev
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p. 1298 - 1300
(2019/07/15)
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- Oxidative ring-opening of isatins for the synthesis of 2-aminobenzamides and 2-aminobenzoates
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An efficient and practical isatin-based oxidative domino protocol has been developed for the facile synthesis of 2-aminobenzamides and 2-aminobenzoates. The robust nature of this reaction system is reflected by accessible starting materials, room temperature and high-yield gram-scale synthesis.
- Wang, Yu-Wei,Zheng, Lei,Jia, Feng-Cheng,Chen, Yun-Feng,Wu, An-Xin
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p. 1497 - 1503
(2019/02/13)
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- Chemoselectivity for Alkene Cleavage by Palladium-Catalyzed Intramolecular Diazo Group Transfer from Azide to Alkene
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Alkenes can be cleaved by means of the (3+2) cycloaddition and subsequent cycloreversion of 1,3-dipoles, classically ozone (O3), but the azide (R?N3) variant is rare. Chemoselectivity for these azide to alkene diazo group transfers (DGT) is typically disfavored, thus limiting their synthetic utility. Herein, this work discloses a palladium-catalyzed intramolecular azide to alkene DGT, which grants chemoselectivity over competing aziridination. The data support a catalytic cycloreversion mechanism distinct from other known metal-catalyzed azide/alkene reactions: nitrenoid/metalloradical and (3+2) cycloadditions. Kinetics experiments reveal an unusual mechanistic profile in which the catalyst is not operative during the rate-controlling step, rather, it is active during the product-determining step. Catalytic DGT was used to synthesize N-heterocyclic quinazolinones, a medicinally relevant structural core. We also report on the competing aziridination and subsequent ring expansion to another N-heterocyclic core structure of interest, benzodiazepinones.
- Frost, Grant B.,Mittelstaedt, Michaela N.,Douglas, Christopher J.
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supporting information
p. 1727 - 1732
(2019/01/09)
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- Utilization of a Hydrogen Source from Renewable Lignocellulosic Biomass for Hydrogenation of Nitroarenes
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Exploring of hydrogen source from renewable biomass, such as glucose in alkaline solution, for hydrogenation reactions had been studied since 1860s. According to proposed pathway, only small part of hydrogen source in glucose was utilized. Herein, the utilization of a hydrogen source from renewable lignocellulosic biomass, one of the most abundant renewable sources in nature, for a hydrogenation reaction is described. The hydrogenation is demonstrated by reduction of nitroarenes to arylamines in up to 95 % yields. Mechanism studies suggest that the hydrogenation occurs via a hydrogen transformation pathway.
- Tan, Fang-Fang,Tang, Kai-Li,Zhang, Ping,Guo, Yan-Jun,Qu, Mengnan,Li, Yang
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p. 4189 - 4195
(2019/03/07)
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- Rapid and reversible hydrazone bioconjugation in cells without the use of extraneous catalysts
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The amenability of hydrazone linkages to disassemble via either hydrolysis in mildly acidic aqueous solutions or transimination upon treatment with amine nucleophiles renders them extremely attractive for applications in chemical biology, drug delivery and materials science. Unfortunately, however, the use of hydrazones is hampered by the extremely slow intrinsic rates of their formation from their hydrazine and carbonyl precursors. Consequently, hydrazone formation is typically performed in the presence of a large excess of cytotoxic aniline-based nucleophilic catalysts, rendering hydrazones unsuitable for biological applications that entail their formation in cells. Herein, we report a hydrazine scaffold - o-amino benzyl hydrazine - that rapidly forms hydrazones via intramolecular nucleophilic catalysis, thereby obviating the use of extraneous catalysts. We demonstrate the use of this scaffold for rapid and reversible peptide and protein hydrazone bioconjugation and also for reversible fluorescent labeling of sialylated glycoproteins and choline lipids in mammalian cells.
- Nisal, Rahul,Jose, Gregor,Shanbhag, Chitra,Kalia, Jeet
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supporting information
p. 4304 - 4310
(2018/06/22)
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- Structure-Guided Synthesis and Mechanistic Studies Reveal Sweetspots on Naphthyl Salicyl Hydrazone Scaffold as Non-Nucleosidic Competitive, Reversible Inhibitors of Human Ribonucleotide Reductase
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Ribonucleotide reductase (RR), an established cancer target, is usually inhibited by antimetabolites, which display multiple cross-reactive effects. Recently, we discovered a naphthyl salicyl acyl hydrazone-based inhibitor (NSAH or E-3a) of human RR (hRR) binding at the catalytic site (C-site) and inhibiting hRR reversibly. We herein report the synthesis and biochemical characterization of 25 distinct analogs. We designed each analog through docking to the C-site of hRR based on our 2.7 ? X-ray crystal structure (PDB ID: 5TUS). Broad tolerance to minor structural variations preserving inhibitory potency is observed. E-3f (82% yield) displayed an in vitro IC50 of 5.3 ± 1.8 μM against hRR, making it the most potent in this series. Kinetic assays reveal that E-3a, E-3c, E-3t, and E-3w bind and inhibit hRR through a reversible and competitive mode. Target selectivity toward the R1 subunit of hRR is established, providing a novel way of inhibition of this crucial enzyme.
- Huff, Sarah E.,Mohammed, Faiz Ahmad,Yang, Mu,Agrawal, Prashansa,Pink, John,Harris, Michael E.,Dealwis, Chris G.,Viswanathan, Rajesh
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supporting information
p. 666 - 680
(2018/02/16)
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- Iodine(III) Reagent-Mediated Intramolecular Amination of 2-Alkenylanilines to Prepare Indoles
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A variety of 3-substituted and 2,3-disubstituted indoles were synthesized efficiently in good yields through the intramolecular amination of 2-alkenylanilines promoted by readily available iodine(III) reagents in a short reaction time. Mechanistic studies showed that the reaction pathway went through a nitrenium ion and that 3-acetoxy indoline was the key intermediate in the indole formation. The indole product was easily prepared on a gram scale and amination also proceeded smoothly using catalytic 3,5-dimethylphenyl iodine in the presence of mCPBA. Furthermore, the indolo[3,2-a]carbazole scaffold was prepared in good yield in six steps from commercial ortho-iodoaniline. (Figure presented.).
- Zhao, Chun-Yang,Li, Kun,Pang, Yu,Li, Jia-Qing,Liang, Cui,Su, Gui-Fa,Mo, Dong-Liang
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supporting information
p. 1919 - 1925
(2018/03/28)
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- Gold promoted arylative cyclization of alkynoic acids with arenediazonium salts
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Alkynoic acids derived from salicylic acid and analogues undergo arylative cyclization with arenediazonium salts promoted by gold in the absence of external ligands. The reaction is thermally induced and proceeds even in the absence of light. A difference in regioselectivity has been found compared with that observed in the cycloisomerization process of the same type of compounds.
- Carrillo-Arcos, Ulises A.,Porcel, Susana
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supporting information
p. 1837 - 1842
(2018/03/23)
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- Structural design, synthesis and substituent effect of hydrazone-N-acylhydrazones reveal potent immunomodulatory agents
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4-(Nitrophenyl)hydrazone derivatives of N-acylhydrazone were synthesized and screened for suppress lymphocyte proliferation and nitrite inhibition in macrophages. Compared to an unsubstituted N-acylhydrazone, active compounds were identified within initial series when hydroxyl, chloride and nitro substituents were employed. Structure-activity relationship was further developed by varying the position of these substituents as well as attaching structurally-related substituents. Changing substituent position revealed a more promising compound series of anti-inflammatory agents. In contrast, an N-methyl group appended to the 4-(nitrophenyl)hydrazone moiety reduced activity. Anti-inflammatory activity of compounds is achieved by modulating IL-1β secretion and prostaglandin E2 synthesis in macrophages and by inhibiting calcineurin phosphatase activity in lymphocytes. Compound SintMed65 was advanced into an acute model of peritonitis in mice, where it inhibited the neutrophil infiltration after being orally administered. In summary, we demonstrated in great details the structural requirements and the underlying mechanism for anti-inflammatory activity of a new family of hydrazone-N-acylhydrazone, which may represent a valuable medicinal chemistry direction for the anti-inflammatory drug development in general.
- Meira, Cássio S.,dos Santos Filho, José Maurício,Sousa, Caroline C.,Anjos, Pamela S.,Cerqueira, Jéssica V.,Dias Neto, Humberto A.,da Silveira, Rafael G.,Russo, Helena M.,Wolfender, Jean-Luc,Queiroz, Emerson F.,Moreira, Diogo R.M.,Soares, Milena B.P.
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p. 1971 - 1985
(2018/03/12)
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- Heterogeneous Iron-Catalyzed Hydrogenation of Nitroarenes under Water-Gas Shift Reaction Conditions
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Reduction of various nitroarenes in the presence of heterogeneous iron oxide-based catalyst Fe 2 O 3 /NGr@C under water-gas shift reaction (WGSR) conditions has been demonstrated. The catalytic material is prepared in a straightforward manner via deposition/pyrolysis of iron-phenanthroline complex on carbon support. It shows high chemoselectivity towards the reduction of nitroarenes in the presence of other reducible and/or poisoning-capable functional groups. Hydrogenation is achieved using CO/H 2 O as a hydrogen source. Furthermore, it is demonstrated that the presence of triethylamine additive has a significant positive effect on the rate of reduction.
- Ryabchuk, Pavel,Junge, Kathrin,Beller, Matthias
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supporting information
p. 4369 - 4376
(2018/11/21)
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- Metal-free Reduction of Nitro Aromatics to Amines with B 2 (OH) 4 /H 2 O
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A metal-free reduction of nitro aromatics mediated by diboronic acid with water as both the hydrogen donor and solvent under mild conditions has been developed. A series of aromatic amines were obtained with good functional group tolerance and in good yields.
- Chen, Danyi,Zhou, Yanmei,Zhou, Haifeng,Liu, Sensheng,Liu, Qixing,Zhang, Kaili,Uozumi, Yasuhiro
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supporting information
p. 1765 - 1768
(2018/06/26)
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- Cu-catalyzed reduction of azaarenes and nitroaromatics with diboronic acid as reductant
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A ligand-free copper-catalyzed reduction of azaarenes with diboronic acid as reductant in an aprotic solvent under mild conditions has been developed. Most interestingly, the nitroazaarenes could be reduced exclusively to give the corresponding amines without touching the azaarene moieties. Furthermore, the reductive amination of aromatic nitro compounds and aromatic aldehydes has also been realized. A series of hydrogenated azaarenes and secondary amines were obtained with good functional group tolerance.
- Pi, Danwei,Zhou, Haifeng,Zhou, Yanmei,Liu, Qixing,He, Renke,Shen, Guanshuo,Uozumi, Yasuhiro
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p. 2121 - 2129
(2018/03/23)
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- Conversion of alcohols to alkyl esters and carboxylic acids using heterogeneous palladium-based catalysts
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Disclosed are methods for synthesizing an ester or a carboxylic acid from an organic alcohol. To form the ester one reacts, in the presence of oxygen gas, the alcohol with methanol or ethanol. This reaction occurs in the presence of a catalyst comprising palladium and a co-catalyst comprising bismuth, tellurium, lead, cerium, titanium, zinc and/or niobium (most preferably at least bismuth and tellurium). Alternatively that catalyst can be used to generate an acid from that alcohol, when water is also added to the reaction mix.
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- Water as a hydrogen source in palladium-catalyzed reduction and reductive amination of nitroarenes mediated by diboronic acid
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An unprecedented palladium-catalyzed chemoselective reduction and reductive amination of nitroarenes with water as a hydrogen source mediated by diboronic acid have been discovered. A series of aryl amines containing various reducible functional groups were obtained in good to excellent yields.
- Zhou, Yanmei,Zhou, Haifeng,Liu, Sensheng,Pi, Danwei,Shen, Guanshuo
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p. 3898 - 3904
(2017/06/13)
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- Chemoselective Reductive Heterocyclization by Controlling the Binomial Architecture of Metal Particles and Acid-Base Properties of the Support
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2,1-Benzisoxazoles have been selectively synthesized through reductive heterocyclization of 2-nitroacylarenes using Pt-supported nanoparticles. The reaction involves a cascade process in which the first step is the reduction of the nitro group into hydroxylamine followed by heterocyclization through the nucleophilic attack of the hydroxylamine group to the carbonyl of the acyl group and further dehydration. The reaction was performed on Pt/C, Pt/TiO2, and Pt/MgO using hydrogen as the reducing agent under mild reaction conditions. The results showed that Pt/MgO was the most active and selective catalyst. The study of the influence of the crystal size of the metal on the activity and selectivity, combined with the reaction mechanism examined by in situ Fourier transform infrared spectroscopy of the adsorbed reactant, showed that the maximum activity and selectivity to the target compound can be achieved by controlling the architecture of metal particles and acid-base properties of the support. The effect of temperature on selectivity, the stability of the Pt/MgO catalyst, and the scope of the reaction have been studied. Finally, reductive heterocyclization using different metals (Pd and Au) supported on MgO has also been performed.
- Marti,Sanchez,Climent, Maria J.,Corma,Iborra,Romanelli,Concepcion
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p. 8255 - 8262
(2017/12/08)
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- Dibenzothiophene Sulfoximine as an NH3 Surrogate in the Synthesis of Primary Amines by Copper-Catalyzed C?X and C?H Bond Amination
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Readily accessible dibenzothiophene sulfoximine is an NH3 surrogate allowing the preparation of free anilines by copper-catalyzed cross-coupling reactions with aryl iodides or amides followed by radical S?N bond cleavage. The one-pot/two-step r
- Li, Zhen,Yu, Hao,Bolm, Carsten
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supporting information
p. 9532 - 9535
(2017/08/01)
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- Efficient and selective palladium-catalyzed direct oxidative esterification of benzylic alcohols under aerobic conditions
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A highly efficient palladium-catalyzed approach for the direct oxidative esterification of benzylic alcohols with methanol and long-chain aliphatic alcohols under mild conditions has been achieved. This practical catalyst system exhibits a broad substrate scope and good functional group tolerance. Catalytic amount of Bi(OTf)3 is used as co-catalyst to improve the activity and selectivity of the reactions. A variety of esters are obtained in yields of 43–96%.
- Hu, Yongke,Li, Bindong
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p. 7301 - 7307
(2017/11/29)
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- A highly efficient heterogeneous copper-catalysed cascade reaction of aryl iodides with acetamidine hydrochloride leading to primary arylamines
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A highly efficient heterogeneous copper-catalysed cascade reaction of aryl iodides with acetamidine hydrochloride was achieved in DMF in the presence of 10 mol% of an MCM-41-immobilised L-proline-copper(I) complex (MCM-41-L-proline-CuI) with Cs2CO3 as base, yielding a variety of primary arylamines in good to excellent yields. The new heterogeneous copper complex can be easily prepared from commercially readily available and inexpensive reagents, recovered by a simple filtration of the reaction solution and used at least seven more times without any decrease in activity.
- Huang, Xue,Xiao, Ruian,You, Chongren,Yan, Tao,Cai, Mingzhong
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p. 315 - 320
(2017/06/19)
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- Investigation into the stability and reactivity of the pentacyclic alkaloid dehydroevodiamine and the benz-analog thereof
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Limited synthetic approaches to obtain the biologically active alkaloid dehydroevodiamine (DHED) are known to date. Undesired demethylation in the most widely applied route was found to be a hampering side reaction for the benz-DHED derivative leading to a quinazolinone, which represents a benz-rutaecarpine derivative. For rutaecarpine, a related plant alkaloid, many different synthetic approaches have been described. Alternative reaction procedures to obtain DHED such as methylation of rutaecarpine and oxidation of evodiamine were investigated to make DHED more easily accessible and the latter method proved to be the most successful one. Furthermore, the remarkable equilibrium between the ring closed quinazolinium and the ring open form of the compounds was systematically investigated by UV-vis measurements. The ring open form and the quinazolinium salt, form the same species when incubated in buffer solution for 24 h. A better soluble form, i.e., 'hydroxyevodiamine', seems to represent the biologically active form that has not yet been described.
- Wehle, Sarah,Espargaró, Alba,Sabaté, Raimon,Decker, Michael
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supporting information
p. 2535 - 2543
(2016/04/26)
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- A kind of 3,4-dichloro-thiazole derivatives and process for their preparation and use
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The invention provides 3,4-dichloro isothiazole derivatives, their preparation method and application. The invention relates to a heterocyclic compound containing 3,4-dichloro isothiazol, and the compound is represented by the following chemical structural general formula. The invention discloses the structural general formula of the compound, a synthetic method of the compound and applications of the compound as pesticide, bactericide, anti-plant virus agent, and plant activator, and a technology of mixing the compound with agriculturally acceptable auxiliary agents or synergists for preparing pesticide, bactericide, anti-plant virus agent, and plant activator. The invention further discloses the combined application of the compound and the commercial pesticide, bactericide, anti-plant virus agent, and plant activator in controlling diseases, insect pests, and virus diseases in agriculture, forestry and gardening, and a preparation method of the compound and the commercial pesticide, bactericide, anti-plant virus agent, and plant activator.
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Paragraph 0053-0056; 0103
(2016/10/08)
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- Water-Soluble Molecularly Imprinted Nanoparticle Receptors with Hydrogen-Bond-Assisted Hydrophobic Binding
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Molecularly imprinted nanoparticles (MINPs) were prepared when surfactants with a tripropargylammonium headgroup and a methacrylate-functionalized hydrophobic tail were cross-linked in the micelle form on the surface and in the core in the presence of hydrophobic template molecules. With the surfactants containing an amide bond near the headgroup, the MINPs had a layer of hydrogen-bonding groups in the interior that strongly influenced their molecular recognition. Templates/guests with strong hydrogen-bonding groups in the midsection of the molecule benefited most, especially if the hydrophobe of the template could penetrate the amide layer to reach the hydrophobic core of the cross-linked micelles. The location and the orientation of the hydrophilic groups were also important, as they determined how the template interacted with the surfactant micelles and, ultimately, with the MINP receptors.
- Arifuzzaman, Md,Zhao, Yan
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p. 7518 - 7526
(2016/09/09)
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- Synthetic studies and antibacterial activity of nucleobases and their N- and S-glucosides from 2-amino benzoic acid and its benzamido derivatives
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A series of S-glucosides 11a-14a and their benzamido derivatives 11b-14b have been synthesized by reacting D-glucose with thiol groups of 5-(2′-aminophenylene)-1,3,4-oxadiazole-2-thioles 7(a,b), 5-(2′-aminophenylene)-1,3,4-thiadiazole-2-thiols 8(a,b), 5-(2′-aminophenylene)-1,2,4-triazole-3-thiols 9(a,b) and 5-(2′-aminophenylene)-4-N-amino-1,2,4-triazole-3-thiols 10(a,b). The thiols 7(a,b)-10(a,b) have been synthesized from hydrazides 3(a,b) which already been synthesized from 2-aminobenzoic acid and its benzamido derivative. All synthesized compounds were characterized by IR, UV,1H- and13C- NMR. Nucleobases and a representative of S-glycoside were tested in vitro against the following microorganisms: two Gram-positive bacteria Staphylococcus aureus and Bacillus cereusand two Gram-negative bacteria Escherichia coli, Pseudomonas aeruginosa and they exhibited significant effects. Amykacine was used as positive standard.
- Benhammadi, Samia,Iraten, Salima,Othman, Adil A.
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p. 2567 - 2576
(2016/11/22)
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- Triazolylthioacetamide: A Valid Scaffold for the Development of New Delhi Metallo-β-Lactmase-1 (NDM-1) Inhibitors
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The metallo-β-lactamases (MβLs) cleave the β-lactam ring of β-lactam antibiotics, conferring resistance against these drugs to bacteria. Twenty-four triazolylthioacetamides were prepared and evaluated as inhibitors of representatives of the three subclasses of MβLs. All these compounds exhibited specific inhibitory activity against NDM-1 with an IC50 value range of 0.15-1.90 μM, but no activity against CcrA, ImiS, and L1 at inhibitor concentrations of up to 10 μM. Compounds 4d and 6c are partially mixed inhibitors with Ki values of 0.49 and 0.63 μM using cefazolin as the substrate. Structure-activity relationship studies reveal that replacement of hydrogen on the aromatic ring by chlorine, heteroatoms, or alkyl groups can affect bioactivity, while leaving the aromatic ring of the triazolylthiols unmodified maintains the inhibitory potency. Docking studies reveal that the typical potent inhibitors of NDM-1, 4d and 6c, form stable interactions in the active site of NDM-1, with the triazole bridging Zn1 and Zn2, and the amide interacting with Lys 211 (Lys224).
- Zhai, Le,Zhang, Yi-Lin,Kang, Joon S.,Oelschlaeger, Peter,Xiao, Lin,Nie, Sha-Sha,Yang, Ke-Wu
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supporting information
p. 413 - 417
(2016/05/19)
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- Synthesis, Antimicrobial and Anticancer Evaluation of 2-Azetidinones Clubbed with Quinazolinone
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A novel series of 2-azetidinones clubbed with quinazolinone was synthesized using anthranilic acid. All the synthesized compounds were evaluated for their antimicrobial activity against two Gram positive bacterial strains (Bacillus subtilis and Staphyloco
- Deep, Aakash,Kumar, Pradeep,Narasimhan, Balasubrmanian,Meng, Lim Siong,Ramasamy, Kalavathy,Mishra, Rakesh Kumar,Mani, Vasudevan
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- Antiurease, antiphosphodiesterase and antiglycation studies of Pd(II) complexes with monodentate hydrazides
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The present study was aimed to synthesize and characterize a series of Pd(II)-benzohydrazide complexes with subsequent high throughput screening to seek their effects as enzyme inhibitors and antiglycating agents. Based on complete characterization via elemental (CHN, Pd) analysis, physical (conductivity, magnetic moment) measurements and spectral (FT-IR, 1H-NMR, 13C-NMR) techniques, all Pd(II) complexes were identified as diamagnetic, neutral and orienting in trans square planar geometry with general formula [PdL2Cl2]. The benzohydrazide (L) in these complexes depicts monodentate behavior, providing terminal amino nitrogen as a donor atom. Compared to inactive precursors (free benzohydrazides and Pd2+), almost all Pd(II) complexes showed in vitro antiglycation activity, illustrating the potential role of resulting complexes in the suppression of diabetes and related disorders. The presence of free carbonyl group in complexes has been recognized as possible cause of antiglycation. This study also indicated Pd(II) compounds as far more superior inhibitors of urease and phosphodiesterase-I than parent ligands; many of them exhibited inhibitions equivalent or even greater than the standard inhibitors (thiourea, urease; EDTA, phosphodiesterase), which shows their potential use in future in the control of peptic ulcer and arthritis, respectively. The structure activity relationship (SAR) study demonstrated that complexation, steric hindrance, position of substituents, electron density around metal centre, hydrogen bonding and coordination mode of complexed ligands play prime role in modulating the biological activities of complexes.
- Qurrat-Ul-Ain,Rasheed, Saima,Mahroof-Tahir, Mohammad,Ashiq, Uzma,Jamal, Rifat Ara,Khurshid, Sumaira,Mustafa, Sana
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p. 864 - 881
(2016/11/21)
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- Method of preparing 2-chlorosulfonylmethyl benzoate from phthalic anhydride and urea
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The invention provides a method of preparing 2-chlorosulfonylmethyl benzoate from phthalic anhydride and urea. The method includes the steps of 1) adding solid phthalic anhydride and urea into a reaction kettle and heating the materials to 135-143 DEG C to carry out a reaction to prepare o-aminobenzene dicarboximide, feeding the o-aminobenzene dicarboximide with water and sodium hydroxide into a first tubular reactor, forcedly cooling the mixture to -12 - -15 DEG C; 2) adding methanol and a sodium hypochlorite solution to perform Hoffman degradation reaction, and separating the reaction product to obtain o-aminomethyl benzoate; 3) according to the same mass ratio, feeding the o-aminomethyl benzoate and a sodium nitrite solution to a second tubular reactor, cooling the reactants to 0 DEG C, and adding sulfuric acid to perform a diazo-reaction for 11.5-11.8 s; and 4) continuously performing a cyclic sulfurization oxidation tubular reaction for 2 h, when the reactants show a dark green color on an benzidine-ethylamine test paper, adding methylbenzene and separating the reactant to obtain the 2-chlorosulfonylmethyl benzoate. The method is safe and simple, is advanced and integrated, is high in synthesis efficiency, has less side reactions and greatly reduces influence due to human factors.
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Paragraph 0029
(2017/01/17)
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- Copper-Catalyzed O-Methylation of Carboxylic Acids Using DMSO as a Methyl Source
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A copper-catalyzed O-methylation of carboxylic acids using dimethyl sulfoxide (DMSO) as the methyl source is disclosed. This transformation exhibits a broad substrate scope and excellent functional group tolerance. Mechanistic studies indicate that a methyl radical is generated from dimethyl sulfoxide in the reaction process.
- Jia, Jing,Jiang, Qing,Zhao, An,Xu, Bin,Liu, Qiang,Luo, Wei-Ping,Guo, Can-Cheng
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p. 421 - 428
(2016/01/28)
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- Oxidative cyclization of alkenoic acids promoted by AgOAc
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Alkenoic acids derived from salicylic acid and analogues undergo an unexpected oxidative cyclization process triggered by AgOAc leading to 4H-benzo[d][1,3]dioxin-4-ones. The process is affected by the substitution on the aryl and the allyl units.
- Carrillo-Arcos, Ulises A.,Rojas-Ocampo, Jonathan,Porcel, Susana
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supporting information
p. 479 - 483
(2016/01/09)
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- NEW ORGANIC ELECTROLUMINESCENT COMPOUNDS AND ORGANIC ELECTROLUMINESCENT DEVICE COMPRISING THE SAME
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The present invention relates to an organic compound represented by Chemical Formula 1 and an organic electroluminescent device comprising the same: [Chemical Formula 1]. The organic luminescent compound is a material of a luminescent layer, a hole injection layer, a hole transport layer, an electron injection layer, an electron transport layer, an electron blocking layer and a hole blocking layer and can be applied to an organic electroluminescent device, wherein the luminescent efficiency and the lifespan of the organic electroluminescent device can be improved.COPYRIGHT KIPO 2015
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Paragraph 0290-0293
(2016/10/08)
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- A Mild and Chemoselective Reduction of Nitro and Azo Compounds Catalyzed by a Well-Defined Mo3S4 Cluster Bearing Diamine Ligands
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Herein, we report a novel well-defined diamino Mo3S4-based catalyst system for the reduction of nitroarenes and azo compounds to the corresponding anilines with silanes as reducing agents. This catalytic protocol provides a facile route to access aromatic amines under mild conditions in good to excellent yields. Notably, even anilines functionalized with other potentially reducible moieties are obtained with high selectivity. The new chemoselective catalyst of formula [Mo3S4Cl3(dmen)3](BF4) (dmen: N,N′-dimethylethylenediamine) is conveniently synthesized through coordination of the diamine ligand to the incomplete Mo3S4 cubane-type cluster core in a one-pot two-step procedure. The crystal structure of the [Mo3S4Cl3(dmen)3]+ cation confirms the formation of a single isomer in which the chlorine atom lies trans to the bridging sulfur atom to afford a C3 symmetry complex with intrinsic backbone chirality. The structure is preserved in solution, as evidenced by multinuclear NMR spectroscopy and electrospray-ionization mass spectrometric techniques.
- Pedrajas, Elena,Sorribes, Iván,Junge, Kathrin,Beller, Matthias,Llusar, Rosa
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p. 2675 - 2681
(2015/09/15)
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- Beyond conventional routes, an unprecedented metal-free chemoselective synthesis of anthranilate esters via a multicomponent reaction (MCR) strategy
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A hitherto unreported route for the synthesis of anthranilate esters is demonstrated using 2-nitrobenzaldehyde, malonitrile and an alcohol or amine via a metal and oxidant free multicomponent reaction (MCR) strategy. This process simultaneously installs an ester and urea or urethane functionality via CO and CN bond formations via concurrent oxidation of the aldehyde group and reduction of the nitro group involving an intramolecular redox process.
- Sarkar, Satavisha,Khan, Abu T.
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supporting information
p. 12673 - 12676
(2015/08/06)
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