- Highly robust magnetically recoverable Ag/Fe2O3 nanocatalyst for chemoselective hydrogenation of nitroarenes in water
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This work reports on additive-free Ag nanoparticles (4–6?nm) deposition on magnetic α-Fe2O3 nanocrystals surface by the slow reduction of AgNO3 with NaBH4 in aqueous medium. The EDS analysis revealed that the new materials contain 3.93?wt% of Ag nanoparticle on the surface of α-Fe2O3 which are the active suite for hydrogenation reaction. The Ag/Fe2O3 nanocatalysts exhibited good catalytic ability toward chemoselective hydrogenation of nitroarenes in water. LC–MS study suggested that the catalytic reaction pathway is –NO2, –NHOH, –NH2 and certainly skips the nitrosoarene intermediate step. The nanocatalysts are very efficient in the hydrogenation of nitroarenes tolerating –H, –Br, –I, –OH, –OCH3, –COOH and –CONH2 functional groups. The nanocatalysts were separated by external magnet and recycled in aqueous medium which offer environmentally and safe approach to this hydrogenation reaction. The catalyst was tested up to 10 recycles and showed no significant loss of catalytic activity.
- Patra, Astam K.,Vo, Nhat Tri,Kim, Dukjoon
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Read Online
- Exploration of Fragment Binding Poses Leading to Efficient Discovery of Highly Potent and Orally Effective Inhibitors of FABP4 for Anti-inflammation
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Fatty-acid binding protein 4 (FABP4) is a promising therapeutic target for immunometabolic diseases, while its potential for systemic inflammatory response syndrome treatment has not been explored. Here, a series of 2-(phenylamino)benzoic acids as novel and potent FABP4 inhibitors are rationally designed based on an interesting fragment that adopts multiple binding poses within FABP4. A fusion of these binding poses leads to the design of compound 3 with an ?460-fold improvement in binding affinity compared to the initial fragment. A subsequent structure-aided optimization upon 3 results in a promising lead (17) with the highest binding affinity among all the inhibitors, exerting a significant anti-inflammatory effect in cells and effectively attenuating a systemic inflammatory damage in mice. Our work therefore presents a good example of lead compound discovery derived from the multiple binding poses of a fragment and provides a candidate for development of drugs against inflammation-related diseases.
- Su, Haixia,Zou, Yi,Chen, Guofeng,Dou, Huixia,Xie, Hang,Yuan, Xiaojing,Zhang, Xianglei,Zhang, Naixia,Li, Minjun,Xu, Yechun
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p. 4090 - 4106
(2020/05/20)
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- Copper complexes of 1,4-diazabutadiene ligands: Tuning of metal oxidation state and, application in catalytic C-C and C-N bond formation
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Reaction of 1,4-diazabutadiene (p-RC6H4N = C(H)(H)C = NC6H4R-p; R = OCH3, CH3, H and Cl; abbreviated as L-R) with CuCl2·2H2O in methanol at ambient temperature (25 °C) affords a group of doubly chloro-bridged dicopper complexes of type [{CuI(L-R)Cl}2], designated as 1-R. Similar reaction carried out in acetonitrile furnishes a family of doubly chloro-bridged dicopper complexes of type [{CuII(L-R)Cl2}2], designated as 2-R. Molecular structures of 1-OCH3 and 2-OCH3 have been determined by X-ray crystallography. While copper(I) is having a nearly tetrahedral N2Cl2 coordination sphere in 1-OCH3, the N2Cl3 coordination sphere around copper(II) is distorted square pyramidal in nature in 2-OCH3. Isolated 2-R complexes, on dissolution in methanol, are found to undergo facile reduction of the metal center to generate the corresponding 1-R complexes. The 1-R and 2-R complexes show intense absorptions in the visible and ultraviolet regions. Cyclic voltammetry on the 1-R and 2-R complexes shows both metal-centered and ligand centered redox responses. The 1-R complexes are found to efficiently catalyze C-N cross-coupling reactions between arylboronic acids and aryl amines; while the 2-R complexes display notable catalytic efficiency for nitroaldol reactions.
- Mukherjee, Aparajita,Basu, Semanti,Bhattacharya, Samaresh
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- COMPOUND AND ORGANIC ELECTRONIC DEVICE USING THE SAME
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Provided are a novel compound and an organic electronic device using the same. The novel compound is represented by the following Formula (I): wherein Y is an oxygen atom or a sulfur atom; X1 and X2 are each independently C(Ra), the two (Ra)s are the same or different, and the two (Ra)s are joined together to form a first aryl ring; X3 and X4 are each independently C(Rb), the two (Rb)s are the same or different, and the two (Rb)s are joined to form a second aryl ring or a heteroaryl ring.
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- A 3 - benzofuran bromine two synthetic method (by machine translation)
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The invention relates to a 3 - benzofuran bromine two synthetic method, which belongs to the field of organic synthesis, the method uses 2 - fluoro nitrobenzene and phenol as the starting material, through the nucleophilic substitution reaction synthesis of 2 - nitro-diphenyl ether, reduction to obtain 2 - amino-diphenyl ether, brominated to obtain 2 - amino - 5 - bromine two ether, diazotization to obtain the corresponding four fluoro boric acid diazonium salt, ferrous sulfate obtained by catalytic ring 3 - bromine two benzofuran. The route of low raw material cost, high product yield, simple process operation, while avoiding the use of the noble metal catalyst, in the industrial production has significant economic advantage and environmental protection. (by machine translation)
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- Cell-Based Optimization of Covalent Reversible Ketoamide Inhibitors Bridging the Unprimed to the Primed Site of the Proteasome β5 Subunit
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The ubiquitin-proteasome system (UPS) is an established therapeutic target for approved drugs to treat selected hematologic malignancies. While drug discovery targeting the UPS focuses on irreversibly binding epoxyketones and slowly-reversibly binding boronates, optimization of novel covalent-reversibly binding warheads remains largely unattended. We previously reported α-ketoamides to be a promising reversible lead motif, yet the cytotoxic activity required further optimization. This work focuses on the lead optimization of phenoxy-substituted α-ketoamides combining the structure-activity relationships from the primed and the non-primed site of the proteasome β5 subunit. Our optimization strategy is accompanied by molecular modeling, suggesting occupation of P1′ by a 3-phenoxy group to increase β5 inhibition and cytotoxic activity in leukemia cell lines. Key compounds were further profiled for time-dependent inhibition of cellular substrate conversion. Furthermore, the α-ketoamide lead structure 27 does not affect escape response behavior in Danio rerio embryos, in contrast to bortezomib, which suggests increased target specificity.
- Stubba, Daniel,Bensinger, Dennis,Steinbacher, Janika,Proskurjakov, Lilia,Salcedo Gómez, álvaro,Schmidt, Uwe,Roth, Stefan,Schmitz, Katja,Schmidt, Boris
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p. 2005 - 2022
(2019/11/22)
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- Synthesis and biological evaluation of vanadium complexes as novel anti-tumor agents
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A class of vanadium complexes were prepared and investigated for their antiproliferative effects by MTT assay. The structure-activity relationship was extensively studied through the ligand variation. The results showed that the synthetic vanadium complexes demonstrated moderate to good antiproliferative activities against the four cancer cell lines including MGC803, EC109, MCF7 and HepG2, respectively. Of note was that most of the complexes showed preferential growth inhibitory activity to some degree toward gastric cancer line MGC803. Among them, complex 19 exhibited the most and broad-spectrum proliferative inhibition against the tested cell lines. In addition, mechanism studies illustrated that complex 19 could prevent the colony formation, migration and EMT process, as well as induce apoptosis of MGC803 cells. Furthermore, Western blot experiments revealed that the expression of apoptosis-related proteins changed, including up-regulation of Bax, PARP and caspase-3/9, as well as down-regulation of Bcl-2.
- Lu, Ling-Pan,Suo, Feng-Zhi,Feng, Ya-Li,Song, Li-Li,Li, Ying,Li, Yang-Jie,Wang, Kai-Ti
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- COMPOUND AND ORGANIC ELECTRONIC DEVICE USING THE SAME
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Provided are a novel compound and an organic electronic device using the same. The novel corn pound is represented by the following Formula (I): wherein Y is an oxygen atom, a sulfur atom, or a sulfur dioxide group; X1 and X2 are each independently C(Ra), multiple (Ra)s are the same or different, and the two (Ra)s are joined together to form a first aryl ring; X3 and X4 are each independently C(Rb), multiple (Rb)s are the same or different, and the two (Rb)s are joined to form a second aryl ring or a heteroaryl ring.
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- 8-exo-dig-Selective Cycloisomerization for the Synthesis of Dibenzo[b,e][1,4]diazocines Using Cationic AuI Catalysts
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The cationic AuI-catalyzed intramolecular reaction of N-propargyl-2-anilinoanilines gave a diazocine skeleton via 8-exo-dig-selective cycloisomerization by the suppression of 6-endo-dig cycloisomerization. Both terminal and internal alkynes could be used according to the choice of ligand of the AuI complex, and various dibenzo[b,e][1,4]diazocines were obtained. Control experiments suggested that two nitrogen atoms in the tether of substrates were critical in this selective transformation.
- Ito, Mamoru,Inoue, Daisuke,Takaki, Asahi,Kanyiva, Kyalo Stephen,Shibata, Takanori
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p. 4740 - 4747
(2018/09/14)
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- COMPOUND AND ORGANIC ELECTRONIC DEVICE USING THE SAME
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Provided are a novel compound and an organic electronic device using the same. The novel compound is represented by the following Formula (I): wherein Y is an oxygen atom or a sulfur atom; X 1and X 2are each independently C(R a), the two(R a)s are the same or different, and the two (R a)s are joined together to form a first aryl ring; X 3and X 4are each independently C(R b), the two (R b)s are the same or different, and the two (R b)s are joined to form a second aryl ring or a heteroaryl ring.
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- 4-bromine-2-picolinamide compound containing diphenyl ether structure
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The invention relates to a 4-bromine-2-picolinamide compound containing a diphenyl ether structure. A target compound is synthesized by taking 2-phenoxyaniline and 4-bromine-2-picolinic acid as raw materials under the condition of alkali, a condensing agent and an organic solvent through one-step reaction. The compound has high bactericidal activity and herbicidal activity, the preparation methodis simple and convenient, and the yield is high.
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Paragraph 0033; 0038; 0043; 0048; 0053; 0058
(2018/11/22)
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- 5-trifluoromethyl-2-picolinamide compound and preparing method and application thereof
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The invention relates to the technical field of organic chemistry synthesis, and particularly discloses a 5-trifluoromethyl-2-picolinamide compound and a preparing method and application thereof. 2-phenoxy nitrobenzene serves as a raw material of the 5-trifluoromethyl-2-picolinamide compound for a reduction reaction to obtain 2-phenoxyaniline; then 5-trifluoromethyl-2-picolinic acid serves as a raw material for a condensation acylation reaction to obtain the 5-trifluoromethyl-2-picolinamide compound. By means of the 5-trifluoromethyl-2-picolinamide compound, pyridine carboxylic acid and diphenyl ether perssads are combined in the same molecule; the 5-trifluoromethyl-2-picolinamide compound has both the herbicidal activity and the bactericidal activity, and particularly has a good effect onpreventing monocotyledonous weeds; moreover, the preparing method is simple, and the yield is high.
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Paragraph 0037-0039
(2018/09/28)
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- Synthesis of medium-sized (6-7-6) ring compounds by iron-catalyzed dehydrogenative C-H activation/annulation
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In this report, we have described a FeCl3-catalyzed process involving intramolecular annulation of o-phenoxy diarylacetylenes via hydroarylation to afford a series of biologically potent fused seven-membered (6-7-6) ring compounds under mild reaction conditions. This reaction was believed to proceed through Friedel-Crafts type sequential carbometallation followed by protonation to produce phenyldibenz[b,f]oxepines. This method was also extended to synthesize seven-membered rings that are fused with coumarins.
- Panda, Niranjan,Mattan, Irshad,Ojha, Subhadra,Purohit, Chandra Shekhar
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supporting information
p. 7861 - 7870
(2018/11/21)
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- Access to Chiral Seven-Member Cyclic Amines via Rh-Catalyzed Asymmetric Hydrogenation
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A highly efficient asymmetric hydrogenation of azepine/oxazepine-type seven-member cyclic imine hydrochlorides was successfully developed using Rh/bisphosphine-thiourea ligand ZhaoPhos, affording various chiral seven-member cyclic amines with full conversions, high yields, and excellent enantioselectivities (up to 96% yield, >99% ee). Additionally, this asymmetric hydrogenation can proceed well on gram scale with excellent ee value. Moreover, control experimental results displayed that the anion-bonding interaction between the chloride ion of the substrate and thiourea motif of the ZhaoPhos played an important role to obtain excellent enantioselectivity.
- Li, Pan,Huang, Yi,Hu, Xinquan,Dong, Xiu-Qin,Zhang, Xumu
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p. 3855 - 3858
(2017/07/26)
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- Fe-Catalyzed Amination of (Hetero)Arenes with a Redox-Active Aminating Reagent under Mild Conditions
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A novel and efficient Fe-catalyzed direct C?H amination (NH2) of arenes is reported using a new redox-active aminating reagent. The reaction is simple, and can be performed under air, mild, and redox-neutral conditions. This protocol has a broad substrate scope and could be used in the late-stage modification of bioactive compounds. Mechanistic studies demonstrate that a radical pathway could be involved in this transformation.
- Liu, Jianzhong,Wu, Kai,Shen, Tao,Liang, Yujie,Zou, Miancheng,Zhu, Yuchao,Li, Xinwei,Li, Xinyao,Jiao, Ning
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supporting information
p. 563 - 567
(2017/01/18)
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- Design, synthesis and antifungal activity of novel furancarboxamide derivatives
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Twenty-seven novel furancarboxamide derivatives with a diphenyl ether moiety were synthesized and evaluated for their antifungal activity against Rhizoctonia solani, Botrytis cirerea, Valsa Mali and Sphaceloma ampelimum. Antifungal bioassay results indicated that most compounds had good or excellent fungicidal activities for R. solani and S. ampelimum at 20 mg L-1. Among synthesized compounds, compound 18e showed a greater inhibitory effect against S. ampelimum, with half maximal effective concentration (EC50) values of 0.020 mg L-1. This strong activity rivals currently used commercial fungicides, such as Boscalid and Carbendazim, and has great potential as a lead compound for future development of novel fungicides.
- Wen, Fang,Jin, Hong,Tao, Ke,Hou, Taiping
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p. 244 - 251
(2016/05/24)
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- PHOTOREDOX-CATALYZED DIRECT C-H FUNCTIONALIZATION OF ARENES
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The invention generally relates to methods of making substituted arenes via direct C-H amination. More specifically, methods of making para- and ortho-substituted arenes via direct C-H amination are disclosed. This abstract is intended as a scanning tool for purposes of searching in the particular art and is not intended to be limiting of the present invention.
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Paragraph 00349; 00384
(2017/01/31)
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- Four- and Sixfold Tandem-Domino Reactions Leading to Dimeric Tetrasubstituted Alkenes Suitable as Molecular Switches
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A highly efficient palladium-catalyzed fourfold tandem-domino reaction consisting of two carbopalladation and two C-H-activation steps was developed for the synthesis of two types of tetrasubstituted alkenes 3 and 6 with intrinsic helical chirality starting from substrates 1 and 4, respectively. A sixfold tandem-domino reaction was also developed by including a Sonogashira reaction. 20 compounds with different substitution patterns were prepared with yields of up to 97%. Structure elucidation by X-ray crystallography confirmed helical chirality of the two alkene moieties. Photophysical investigations of some of the compounds showed pronounced switching properties through light-controlled changes of their stereochemical configuration.
- Tietze, Lutz F.,Waldecker, Bernd,Ganapathy, Dhandapani,Eichhorst, Christoph,Lenzer, Thomas,Oum, Kawon,Reichmann, Sven O.,Stalke, Dietmar
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p. 10317 - 10323
(2015/09/01)
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- For radioactive-derwed Pyridinil deriv. in vivo imaging
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The present invention provides a novel radiolabeled aryloxyalinine derivative suitable for in vivo imaging. In comparison to known aryloxyalinine derivative in vivo imaging agents, the in vivo imaging agent of the present invention has better properties for in vivo imaging. The in vivo imaging agent of the present invention demonstrates good selective binding to the peripheral benzodiazepine receptor (PBR), in combination with good brain uptake and in vivo kinetics following administration to a subject.
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Paragraph 0148; 0149; 0150
(2016/10/09)
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- Site-selective arene C-H amination via photoredox catalysis
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Over the past several decades, organometallic cross-coupling chemistry has developed into one of the most reliable approaches to assemble complex aromatic compounds from preoxidized starting materials. More recently, transition metal-catalyzed carbon-hydrogen activation has circumvented the need for preoxidized starting materials, but this approach is limited by a lack of practical amination protocols. Here, we present a blueprint for aromatic carbon-hydrogen functionalization via photoredox catalysis and describe the utility of this strategy for arene amination. An organic photoredox-based catalyst system, consisting of an acridinium photooxidant and a nitroxyl radical, promotes site-selective amination of a variety of simple and complex aromatics with heteroaromatic azoles of interest in pharmaceutical research. We also describe the atom-economical use of ammonia to form anilines, without the need for prefunctionalization of the aromatic component.
- Romero, Nathan A.,Margrey, Kaila A.,Tay, Nicholas E.,Nicewicz, David A.
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p. 1326 - 1330
(2015/10/12)
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- Synthesis of xanthones through the palladium-catalyzed carbonylation/C-H activation sequence
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A series of xanthones with the dibenzo-γ-pyrone framework were synthesized through the palladium-catalyzed carbonylation/C-H activation sequence from the ortho diazonium salts of diaryl ethers in moderate to excellent yields. After screening the reaction condition, the optimal condition was 5 mol % tetrakis (triphenylphosphine) palladium (0) as the catalyst, potassium carbonate as the base, and toluene as the solvent in the presence of catalytic amount of tetrabutyl ammonium bromide under carbon monoxide atmosphere.
- Xu, Yingmeng,Zhou, Jing,Zhang, Congcong,Chen, Ke,Zhang, Tao,Du, Zhenting
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supporting information
p. 6432 - 6434
(2014/12/10)
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- Chemoselective and ligand-free synthesis of diaryl ethers in aqueous medium using recyclable alumina-supported nickel nanoparticles
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An economical and eco-compatible ligand-free protocol for the synthesis of diaryl ethers has been developed using easily accessible alumina-supported nickel nanoparticles as a stable recyclable heterogeneous catalyst in aqueous medium along with a surfactant (SDS) and a mild base (K2CO3). Various sensitive functional groups like allyl, alkoxycarbonyl, formyl, oxo, chloro, bromo, amine and nitro were tolerated in the aforesaid method. Excellent chemoselectivity was demonstrated through competition experiments.
- Ghatak, Avishek,Khan, Sagar,Roy, Rimi,Bhar, Sanjay
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supporting information
p. 7082 - 7088
(2015/02/02)
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- Betti base as an efficient ligand for copper-catalyzed ullmann coupling of phenol with aryl halides
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GRAPHICAL ABSTRACT A simple, general, and highly efficient Betti base ligand has been developed for copper-catalyzed Ullmann coupling of phenol with aryl halides without the protection of an inert atmosphere. The reaction proceeds smoothly in the presence of K2CO3 as the base and dimethylsulfoxide as the solvent. The catalyst was reused several times with no evident loss of catalytic activity and is environmentally friendly.
- Yang, Li,Yang, Qichao,Shi, Jianxin,Wang, Yufang,Zhang, Mingjie
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supporting information
p. 2468 - 2477
(2014/08/05)
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- Substrate-promoted copper-catalyzed N-arylation of amino alcohols with aryl iodides in water
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An efficient method has been developed for the N-arylation of a variety of water-soluble amino alcohols (1.2 mmol) with aryl iodides (1.0 mmol) in water under CuI-catalyzed conditions. The reaction was conducted via substrate-promoted action and did not require an additional ligand or phase-transfer catalyst, and afforded the desired N-aryl amines in acceptable to excellent yields (64%-93%) under mild reaction conditions with a small excess of the amino alcohol.
- Jin, Ming,Zhao, Dan,He, Guozhen,Tong, Yao,Han, Shiqing
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p. 1651 - 1655
(2013/10/21)
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- Electrochemical C-H amination: Synthesis of aromatic primary amines via N -arylpyridinium ions
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We have developed a new method for C-H amination of aromatic compounds based on electrochemical oxidation of aromatic compounds in the presence of pyridine followed by the reaction of the resulting N-arylpyridinium ions with an alkylamine. This new transformation serves as a powerful method for synthesizing aromatic primary amines from aromatic compounds without using metal catalysts and harsh chemical reagents. High chemoselectivity of the present method is demonstrated by C-H amination of aromatic compounds bearing a nitro group to give a key intermediate for the synthesis of VLA-4 antagonist.
- Morofuji, Tatsuya,Shimizu, Akihiro,Yoshida, Jun-Ichi
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supporting information
p. 5000 - 5003
(2013/05/22)
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- Copper powder catalyzed direct ring-opening arylation of benzazoles with aryl iodides in polyethylene glycol
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The expedient and efficient copper powder catalyzed direct ring-opening arylation of benzazoles with aryl iodides in polyethylene glycol that proceeds in the absence of an added ligand has been developed. The protocol provides facile access to 2-(arylthio)anilines and 2-phenoxyanilines in high yields with a wide tolerance of functional groups. Transmission electron microscopy confirmed that the active catalyst results from the in situ generation of copper nanoparticles under standard reaction conditions, which is an alternative avenue to develop a highly effective metallic copper catalyst. Moreover, the catalytic system can be recycled up to six times. Copyright
- Yao, Lifang,Zhou, Qing,Han, Wei,Wei, Shaohua
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supporting information
p. 6856 - 6860
(2013/02/22)
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- Exploration of the structure-activity relationship of the diaryl anilide class of ligands for translocator protein - Potential novel positron emitting tomography imaging agents
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A series of novel ligands based on the diaryl anilide (DAA) class of translocator protein (TSPO) ligands was synthesised and evaluated as potential positron emitting tomography (PET) ligands for imaging TPSO in vivo. Fluorine-18 labelling of the molecules was achieved using direct radiolabelling or synthon based labelling approaches. Several of the ligands prepared have promising profiles as potential TSPO PET imaging ligands and will be evaluated further as potential clinical imaging agents.
- Wadsworth, Harry,Jones, Paul A.,Chau, Wai-Fung,Durrant, Clare,Morisson-Iveson, Veronique,Passmore, Joanna,O'Shea, Dennis,Wynn, Duncan,Khan, Imtiaz,Black, Andrew,Avory, Michelle,Trigg, William
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p. 5795 - 5800,6
(2020/07/30)
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- Synthesis and enantioselective hydrogenation of seven-membered cyclic imines: Substituted dibenzo[b,f][1,4]oxazepines
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Highly enantioselective hydrogenation of seven-membered cyclic imines, substituted dibenzo[b,f][1,4]oxazepines, was achieved, with up to 94% ee, by using the [Ir(COD)Cl]2/(S)-Xyl-C3*-TunePhos complex as the catalyst in the presence of morpholine-HCl.
- Gao, Kai,Yu, Chang-Bin,Li, Wei,Zhou, Yong-Gui,Zhang, Xumu
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p. 7845 - 7847
(2011/09/13)
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- Novel aryl ether derivatives as antiinflammatory and analgesics
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The diaryl ether moieties have attracted considerable attention of medicinal chemists as they are endowed with a wide range of diverse biological activities. The present study involves synthesis, characterization of some new aryl ethers and evaluation of their antiinflammatory and analgesic activity. A series of new aryl ether derivatives [4(a-h), 5] were prepared by Ullmann's ether condensation. The structures of new compounds are supported by their IR, 1H NMR and Mass spectra. The new derivatives were evaluated for their antiinflammatory and analgesic activity. Among the tested, compound 3 has shown better antiinflammatory and analgesic activity.
- Rashmi,Rao, Gopal Krishna,Devi, Kshama,Shivananda,Swetha,Ga, Suneetha
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experimental part
p. 1401 - 1407
(2012/06/29)
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- Sterically encumbered fluorene-based poly(arylene ether)s containing spiro-annulated substituents on the main chain
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Two novel fluorene-based bisphenol monomers containing spiro-annulated substituents on the middle biphenylene moiety have been synthesized in this study. Through reacting with four 2-trifluoromethyl-activated bisfluoro monomers, two monomers were converted into a series of fluorene-based poly(arylene ether)s by nucleophilic displacement of the fluorine atoms on the terminal benzene ring of bisfluoro monomers. The obtained polymers exhibit weight-average molecular weight up to 2.41 × 105 g/mol in GPC. Thermal analysis studies indicated that these polymers did not show melting endotherms but did show ultrahigh Tg values up to 356 °C in DSC and outstanding thermal stability up to 643 °C for 5% weight loss in TGA under nitrogen atmosphere. The polymers are soluble in a wide range of organic solvents, THF, CHCl3, NMP, DMAc, DMF, toluene, etc., and are insoluble in DMSO and acetone at room temperature. Transparent and flexible films were easily prepared by solution casting from chloroform solution of each of the polymers.
- Huang, Wen Y.,Huang
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experimental part
p. 10355 - 10365
(2011/09/13)
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- CuBr/N,N-dimethylglycine-catalyzed coupling reaction of 2-chlorotrifluoroacetanilides with phenols at mild conditions
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The ortho-substituent effect directed by the CF3CONH group exists in CuBr/N,N-dimethylglycine-catalyzed diaryl ether formation from o-chlorotrifluoroacetanilides and phenols, leading to this coupling reaction proceeding at 80 °C to afford a wide range of diaryl ethers. The halogen-exchange also plays an important role in this transformation because adding potassium iodide is essential for complete conversion.
- Hao, Chao,Zhang, Yihua,Jiang, Yongwen,Ma, Dawei
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scheme or table
p. 1645 - 1650
(2011/06/27)
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- Liquid-liquid-liquid phase transfer catalysis: A novel and green concept for selective reduction of substituted nitroaromatics
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The selective reduction of nitroaromatics to the corresponding amines is an important transformation since many aromatic amines exhibit biological activities and find a multitude of industrial applications, being intermediates for the synthesis of dyes, pharmaceuticals and agrochemicals. A variety of nitroaromatics dissolved in organic solvents was reduced by using aqueous sodium sulfide, and tetrabutylammonium bromide (TBAB) as the phase transfer catalyst by choosing appropriate concentrations which resulted in three immiscible liquid phases. Compared to L-L PTC, the L-L-L PTC offers much higher rates of reaction, better selectivities and repeated use of catalyst. The selectivities for the desired products were 100%.
- Yadav, Ganapati D.,Lande, Sharad V.
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p. 1235 - 1241
(2007/10/03)
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- Structure-based design of caspase-1 inhibitor containing a diphenyl ether sulfonamide
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A series of compounds was designed and prepared as inhibitors of interleukin-1β converting enzyme (ICE), also known as caspase-1. These inhibitors, which employ a diphenyl ether sulfonamide, were designed to improve potency by forming favorable interactions between the diphenyl ether rings and the prime side hydrophobic region. An X-ray crystal structure of a representative member of the diphenyl ether sulfonamide series bound to the active site of caspase-1 was obtained.
- Shahripour, Aurash B,Plummer, Mark S,Lunney, Elizabeth A,Sawyer, Tomi K,Stankovic, Charles J,Connolly, Michael K,Rubin, John R,Walker, Nigel P.C,Brady, Kenneth D,Allen, Hamish J,Talanian, Robert V,Wong, Winnie W,Humblet, Christine
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p. 2779 - 2782
(2007/10/03)
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- The studies of the intramolecular C-F---H-N hydrogen bonding using covalently-linked base pair models of F and A
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Both 1H NMR and X-ray studies revealed that C-F---H-N intramolecular hydrogen bonding is not observed even in covalently-linked base pair models of F and A. These results strongly support the Kool's hypothesis.
- Shibata,Das,Harada,Takeuchi,Bando
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p. 1755 - 1758
(2007/10/03)
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- An improved synthesis of dibenzofurans by a free-radical cyclization
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Reaction conditions for the formation of dibenzofurans from diazotized o-(aryloxy)anilines have been examined. Several promoters (hydroquinone, SnCl2, NaI, CuSO4, FeSO4, etc.) have been discovered; these act as electron donors and promote a free-radical mechanism. The best of these is FeSO4 which shortens the reaction time from hours to minutes and contributes to high yields (77-83%). We have been able to transform the cyclization to a reliable and convenient synthesis.
- Wassmundt,Pedemonte
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p. 4991 - 4994
(2007/10/03)
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- Phase-Transfer-Catalyzed Gomberg-Bachmann Synthesis of Unsymmetrical Biarenes: A Survey of Catalysts and Substrates
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Two problems have hindered the Gomberg-Bachmann (GB) and Pschorr reactions of arenediazonium cations: the instability of the arenediazonium salts and side reactions.Arenediazonium tetrafluoroborate and hexafluorophosphate salts can be prepared in high yield and purity and can be stored safely.Unfortunately, these salts are insoluble in most nonpolar organic solvents.Crown ether complexation or other phase-transfer (pt) catalytic methodology can ameliorate this situation, and reactions conducted by the approaches outlined herein often afforded coupling or cyclization products in high yield and corresponding purity.The use of crown ethers, quarternary 'onium salts, lipophilic carboxylic acid salts, and even the polar cosolvent acetonitrile increase the utility of the ptGB reaction dramatically.Sixty examples of couplings are reported along with an assessment of selectivities.A number of examples are also presented of phase-transfer-type Pschorr cyclizations.In the latter case, the use of potassium superoxide, KO2, is introduced to suppress indazole formation.
- Beadle, James R.,Korzeniowsky, Stephen H.,Rosenberg, David E.,Garcia-Slanga, Blanche J.,Gokel, George W.
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p. 1594 - 1603
(2007/10/02)
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- Azo compounds deriving from 3-amino-4-lower carboalkoxy-benzoic acid-4'-phenoxy anilides and 2-hydroxy-3-naphthoic acid-4'-benzoylamino anilides
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Diazotation of 3-amino-4-carboalkoxy-benzoic acid (4'-phenoxy)-anilides which may be halogenated in said phenoxy nucleus and coupling on 2-hydroxy-3-naphthoic acid-(4'-benzoylamino)-anilides which may be further substituted in said anilide nucleus by halogen, lower alkyl or lower alkoxy, yields azo compounds which are valuable pigments of clear shades and high fastness to migration, light and weather.
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