- A tryptophan-based copper(ii) coordination polymer: catalytic activity towards Suzuki-Miyaura cross-coupling reactions
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Herein, we report the synthesis and crystal structure determination of a new Cu(ii) coordination polymer (CP) with the formula [Cu(l-tryp)(azpy)1/2(H2O)(NO3)]∝ (CP1), which exhibits an unusual tryptophan coordination mode with copper(ii) via carboxylate monodentate binding as well as chelation via Namino and Ocarbonyl groups. CP1 was prepared using the ligand l-tryptophan (l-tryp) and the co-ligand 4,4′-azopyridine (azpy), adapting the mixed-ligand approach and a solvothermal protocol. Single crystal X-ray structural analysis revealed that in CP1, Cu(ii) sites show a distorted octahedral geometry, wherein the ligand l-tryp is coordinated through the carboxylate and amine groups, whereas the co-ligand azpy is coordinated to Cu(ii) ions through the Npyridyl atom and thus maintains a distorted octahedral geometry around the Cu(ii) ions. FT-IR and EPR spectra were also recorded to corroborate the structural analysis. Finally, CP1 was employed as a heterogeneous catalyst for the Suzuki cross-coupling reaction and afforded ~98% yield under normal reaction conditions. This journal is
- Bhasin, K. K.,Husain, Ahmad,Kumar, Girijesh,Kumar, Rakesh,Nar, Kuldeep Kaur,Rani, Pooja,Singh, Amit Pratap
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p. 7855 - 7864
(2021/12/02)
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- The Discovery of Novel ACA Derivatives as Specific TRPM2 Inhibitors that Reduce Ischemic Injury Both in Vitro and in Vivo
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The transient receptor potential melastatin 2 (TRPM2) channel is associated with ischemia/reperfusion injury, inflammation, cancer, and neurodegenerative diseases. However, the limit of specific inhibitors impedes the development of TRPM2-targeted therapeutic agents. To discover more potent and selective TRPM2 inhibitors, 59 N-(p-amylcinnamoyl) anthranilic acid (ACA) derivatives were synthesized and evaluated using calcium imaging and electrophysiology approaches. Systematic structure-activity relationship studies resulted in some potent compounds inhibiting the TRPM2 channel with sub-micromolar half-maximal inhibitory concentration values. Among them, the preferred compound A23 exhibited TRPM2 selectivity over TRPM8 and TRPV1 channels as well as phospholipase A2 and showed neuroprotective activity in vitro. Following pharmacokinetic studies, A23 was further evaluated in a transient middle cerebral artery occlusion model in vivo, which significantly reduced cerebral infarction. These data indicate that A23 might serve as a useful tool for TRPM2-related research as well as a lead compound for the development of therapeutic agents for ischemic injury.
- Zhang, Han,Yu, Peilin,Lin, Hongwei,Jin, Zefang,Zhao, Siqi,Zhang, Yi,Xu, Qingxia,Jin, Hongwei,Liu, Zhenming,Yang, Wei,Zhang, Liangren
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p. 3976 - 3996
(2021/05/04)
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- Gold Catalysts Can Generate Nitrone Intermediates from a Nitrosoarene/Alkene Mixture, Enabling Two Distinct Catalytic Reactions: A Nitroso-Activated Cycloheptatriene/Benzylidene Rearrangement
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Gold-catalyzed reactions of cycloheptatrienes with nitrosoarenes yield nitrone derivatives efficiently. This reaction sequence enables us to develop gold-catalyzed aerobic oxidations of cycloheptatrienes to afford benzaldehyde derivatives using CuCl and nitrosoarenes as co-catalysts (10-30 mol %). Our density functional theory calculations support a novel nitroso-activated rearrangement, tropylium → benzylidene. With the same nitrosoarenes, we developed their gold-catalyzed [2 + 2 + 1]-annulations between nitrosobenzene and two enol ethers to yield 5-alkoxyisoxazolidines using 1,4-cyclohexadienes as hydrogen donors.
- Cheng, Mu-Jeng,Kardile, Rahul Dadabhau,Kuo, Tung-Chun,Liu, Rai-Shung,More, Sayaji Arjun
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p. 5506 - 5511
(2021/07/31)
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- Monosubstituted, Anionic Imidazolyl Ligands from N?H NHC Precursors and Their Activity in Pd-Catalyzed Cross-Coupling Reactions
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We report that treatment of several 2-diphenylphosphinoimidazoles with Pd(II) salts generates monosubstituted N?H NHC?Pd complexes via insertion into the C?P bond. Removal of the N?H proton in situ leads to anionic (X-type) or imidazolyl-Pd complexes that are highly stable and catalytically active, achieving up to 340,000 turnovers at 1 ppm catalyst loading in Suzuki-Miyaura reactions. DFT-calculated Tolman electronic parameters for the sterically small ligands suggest that these ligands are significantly more donating than traditional NHCs, which provides a rationale for rapid cross-coupling catalysis. Excellent reactivity is also demonstrated in Sonogashira reactions. (Figure presented.).
- Clark, Kyle J.,Ess, Daniel H.,Jensen, Christopher A.,Kenney, Karissa C.,Larson, Alexandra J. S.,Martinez, Erin E.,Michaelis, David J.,Nazari, S. Hadi,Smith, Stacey J.,Valdivia-Berroeta, Gabriel A.
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supporting information
(2020/07/06)
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- Sublimable bis(β-iminoenolate)palladium(II) complexes and their application as catalysts in Suzuki-Miyaura reactions
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The Pd(II) complexes strongly chelated by two β-iminoenolate ligands were easily synthesized in only two steps, and purified based on their sublimable and highly stable property. The Pd(II) complexes anchored on a silica surface showed good catalytic activity in Suzuki-Miyaura reactions (up to 99% yield with 0.05 mol% catalyst). They tolerated a wide range of temperature (rt~110 °C) and various solvents, and could be reused multiple times after simple recovering process.
- Kim, Mi Jin,Jung, Myung Jin,Kim, Yeong Joon,Sung, Ha Kyoung,Lee, Ju Young,Ham, Sung Jin,Park, Chan Pil
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supporting information
p. 2989 - 2993
(2018/07/02)
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- Iron catalysis for the synthesis of ligands: Exploring the products of hydrophosphination as ligands in cross-coupling
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Catalytic hydrophosphination is a useful technique for the synthesis of phosphines, however, the phosphine products have been little exploited as ligands in catalysis. We have selected three phosphines prepared by iron catalyzed hydrophosphination and used them as ligands in a series of cross-coupling reactions: Heck, Suzuki-Miyaura and Buchwald-Hartwig. Rather than limit the chemistry to simple cross-coupling partners which are almost guaranteed to perform well in these transformations, industrially relevant substrates which are challenging from and electronic and/or steric perspective, along with substrates which contain several heteroatoms, were explored in order to gauge the true potential of these phosphine ligands.
- Espinal-Viguri, Maialen,Mahon, Mary F.,Tyler, Simon N.G.,Webster, Ruth L.
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- Modular Approach to Heterogenous Catalysis. Manipulation of Cross-Coupling Catalyst Activity
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A new type of robust, heterogeneous, modular Pd catalyst with metal embedded in the gel matrix is presented. The regulatory element of its catalytic activity has been introduced via chemical changes in the gel. The concept is illustrated in a series of Suzuki-Miyaura cross-coupling reactions. The demonstrated catalyst activity variations depend on the structure of the gel.
- Stibingerova, Iva,Voltrova, Svatava,Kocova, Sarka,Lindale, Matthew,Srogl, Jiri
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supporting information
p. 312 - 315
(2016/02/03)
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- Rapid threefold cross-couplings with sterically bulky triarylbismuths under Pd-Cu dual catalysis
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The threefold cross-coupling reactivity of sterically highly demanding bulky triarylbismuths was addressed with task specific Pd-Cu dual catalytic conditions. In this study, an unprecedented hitherto unknown cross-coupling reactivity of sterically bulky triarylbismuths was demonstrated with a diverse range of aryl iodides and bromides. The intermediacy and in situ formation of arylcopper was probed with mesitylcopper in support of the proposed dual catalysis. This study opened up an easy way forward for application of sterically bulky bismuth reagents in threefold aryl-aryl coupling reactions.
- Rao, Maddali L. N.,Dhanorkar, Ritesh J.
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p. 1012 - 1017
(2016/01/16)
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- Heterogeneous Catalysis by Covalent Organic Frameworks (COF): Pd(OAc)2@COF-300 in Cross-Coupling Reactions
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COF-300, an imine-linked, crystalline, and microporous covalent organic framework, modified by coordination of Pd(OAc)2 to its walls, afforded a hybrid material, Pd(OAc)2@COF-300, which was used as an efficient heterogeneous catalyst for cross-coupling reactions. This material showed excellent catalytic activity for the phosphine-free Suzuki-Miyaura, Heck, and Sonogashira cross-coupling reactions with low palladium loadings (0.1mol % Pd). X-ray photoelectron spectroscopy analysis of the catalyst after the reaction showed that PdII is converted to Pd0, which is trapped within the COFs nanopores. This was confirmed by high-resolution transmission electron microscopy. Moreover, promising results were obtained using Pd(OAc)2@COF-300 under continuous-flow conditions for a Suzuki-Miyaura cross-coupling reaction.
- Gon?alves, Raoni S. B.,Deoliveira, Alline B. V.,Sindra, Haryadylla C.,Archanjo, Bráulio S.,Mendoza, Martín E.,Carneiro, Leonardo S. A.,Buarque, Camilla D.,Esteves, Pierre M.
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p. 743 - 750
(2016/03/05)
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- Cyclometalated Pd(ii) and Ir(iii) 2-(4-bromophenyl)pyridine complexes with N-heterocyclic carbenes (NHCs) and acetylacetonate (acac): Synthesis, structures, luminescent properties and application in one-pot oxidation/Suzuki coupling of aryl chlorides containing hydroxymethyl
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A series of cyclopalladated 2-(4-bromophenyl)pyridine (bpp) complexes [Pd(bpp)(NHC)Cl] 1-3, [Pd(bpp)(acac)] 4, cyclometalated iridium(iii) complexes [Ir(bpp)2Cl]25 and [Ir(bpp)2(acac)] 6 have been synthesized and characterized. Their detailed structures have been determined by X-ray diffraction and many intermolecular C-H...X (Cl, Br, π) and π...π interactions were found in their crystals. Cyclometalated complexes 1-4 and 6 exhibit luminescence with emission peaks of 390-543 nm in dichloromethane solution under UV irradiation. Their application to coupling reactions of aryl chlorides containing hydroxymethyl was also investigated. An efficient 3/Cu cocatalyzed oxidation/Suzuki reaction for the synthesis of biarylaldehydes from chloro-phenylmethanol and arylboronic acids in air has been developed. In addition, a 6/3-cocatalyzed one-pot reaction of acetylferrocene, (2-amino-5-chlorophenyl)methanol, and arylboronic acids provided 6-aryl-2-ferrocenylquinolines in moderate to good yields.
- Xu, Chen,Li, Hong-Mei,Xiao, Zhi-Qiang,Wang, Zhi-Qiang,Tang, Si-Fu,Ji, Bao-Ming,Hao, Xin-Qi,Song, Mao-Ping
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p. 10235 - 10247
(2014/06/24)
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- Pyrazole[3,4-e][1,4]thiazepin-7-one derivatives as a novel class of Farnesoid X Receptor (FXR) agonists
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A virtual screening procedure was applied to the discovery of structurally diverse non-steroidal Farnesoid X Receptor (FXR) agonists. From 117 compounds selected by virtual screening, a total of 47 compounds were found to be FXR agonists, with 34 of them showing activity below a concentration of 20 μM. 1H-Pyrazole[3,4-e][1,4]thiazepin-7-one-based hit compound 7 was chosen for hit-to-lead optimization. A large number of 1H-pyrazole[3,4-e][1,4]thiazepin-7- one derivatives was designed, synthesized, and evaluated by a cell-based luciferase transactivation assay for their agonistic activity against FXR. Most of them exhibited low micromolar range of potency and very high efficacy.
- Marinozzi, Maura,Carotti, Andrea,Sansone, Emanuele,MacChiarulo, Antonio,Rosatelli, Emiliano,Sardella, Roccaldo,Natalini, Benedetto,Rizzo, Giovanni,Adorini, Luciano,Passeri, Daniela,De Franco, Francesca,Pruzanski, Mark,Pellicciari, Roberto
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supporting information; experimental part
p. 3429 - 3445
(2012/07/30)
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- From isonitriles to carbenes: Synthesis of new NAC - And NHC-palladium(II) compounds and their catalytic activity
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A series of NAC- and their structurally related NHC-palladium(II) isonitrile complexes, including examples of dinuclear complexes, were prepared. In a second series, NHC-palladium complexes bearing an aryl group on one nitrogen of the NHC ring and different cycloalkyl groups ranging from six- to 15-membered rings have been synthesized. The good yields document the value of the very short route to new palladium(II) NHC complexes. The stuctures have been investigated by crystal structure analyses of some representatives; in addition conformational studies by NMR were conducted. The reactivity in Suzuki cross-coupling reactions was investigated, showing turnover frequencies of up to 18-050 h-1 and a clear correlation of the size of the cycloalkyl moiety with the turnover number achieved for the coupling of chlorobenzene and 2,5-dimethylphenylboronic acid.
- Hashmi, A. Stephen K.,Lothschuetz, Christian,Boehling, Constantin,Rominger, Frank
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scheme or table
p. 2411 - 2417
(2011/06/21)
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- Carbenes made easy: Formation of unsymmetrically substituted N-heterocyclic carbene complexes of palladium(II), platinum(II) and gold(I) from coordinated isonitriles and their catalytic activity
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From palladium(II) or platinum(II) bis(isonitrile) complexes and from gold(I) isonitrile complexes, both easily available from simple precursors, the corresponding mono-N-heterocyclic carbene (NHC) complexes could be obtained selectively in good yields under very mild conditions. The reagents are simple β-chloroammonium salts in the presence of a weak base. Unsymmetric NHC complexes are accessible. Thus over only two steps from simple metal precursors a broad variety of NHC complexes is available, the method is ideal to quickly assemble catalyst libraries. The palladium complexes are active pre-catalysts in Suzuki cross-coupling even with the additional isonitrile ligand on palladium. Copyright
- Hashmi, A. Stephen K.,Lothschuetz, Christian,Boehling, Constantin,Hengst, Tobias,Hubbert, Christoph,Rominger, Frank
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experimental part
p. 3001 - 3012
(2011/03/20)
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- Sodium 2-(2-pyridin-3-ylethylamino)ethyl sulfonate: an efficient ligand and base for palladium-catalyzed Suzuki reaction in aqueous media
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PdCl2, N-donor ligand and base mediated Suzuki coupling reaction of aryl halides and arylboronic acid in water are described. The corresponding Suzuki products were obtained in good to excellent yields.
- Pawar, Shivaji S.,Uppalla, Lavkumar S.,Shingare, Murlidhar S.,Thore, Shivaji N.
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scheme or table
p. 5858 - 5862
(2009/04/04)
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- Efficient protocol for the phosphine-free Suzuki-Miyaura reaction catalyzed by palladium on carbon at room temperature
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A mild and efficient protocol for the phosphine-free Suzuki-Miyaura coupling reaction of aryl bromides with arylboronic acids has been developed which utilizes the commercially available 10% Pd/C (3.5 mol% Pd) in ethanol-water (1:1) and Na2CO3 at room temperature. The reaction is convenient, environmentally benign and generates excellent yields of the coupled products (94-100%). The catalyst can be recycled using simple filtration and washing sequences without significant decrease in the yield of coupling product up to the fourth run.
- Zhang, Guolin
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p. 537 - 542
(2007/10/03)
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- A new precatalyst for the Suzuki reaction - A pyridyl-bridged dinuclear palladium complex as a source of mono-ligated palladiuin(0)
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A dinuclear pyridyl-bridged palladium complex, trans-(P,N)-[PdBr(μ- C5H4N-C2,N)(PPh3)]2 1, was obtained from material isolated from the Suzuki cross-coupling reaction of 2-bromopyridine with 2,4-difluorophenylboronic acid in the presence of catalytic (PPh3)4Pd. Complex 1 is an effective precatalyst for the Suzuki cross-coupling reactions of a variety organoboronic acids and aryl bromides, and represents a useful source of mono-ligated palladium(0), "(Ph3P)Pd(0)".
- Beeby, Andrew,Bettington, Sylvia,Fairlamb, Ian J. S.,Goeta, Andres E.,Kapdi, Anant R.,Niemelae, Elina H.,Thompson, Amber L.
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p. 600 - 605
(2007/10/03)
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- Ligand-free Suzuki-Miyaura reaction catalysed by Pd/C at room temperature
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Ligand-free Suzuki-Miyaura coupling reaction has been developed which utilises a commercially available 10% Pd/C (2.6 mol% Pd) in 2-propanol-H 2O (1/1) and Na3PO4 at room temperature. The reaction is mild and generates excellent yields of the coupled products (90-100%). The catalyst is heterogeneous and ligand-free, and the product isolation is simple.
- Zhang, Guolin
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p. 593 - 595
(2007/10/03)
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- A novel thiourea ligand applied in the Pd-catalyzed Heck, Suzuki and Suzuki carbonylative reactions
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A novel C2 symmetrical and sterically bulky thiourea ligand 1 has been successfully applied to Heck, Suzuki and Suzuki-type carbonylative coupling reactions under aerobic conditions. Since the metal-sulfur bond in the thiourea complexes is stronger than the metal-phosphorus bond of typical phosphine complexes, thiourea ligands generally do not easily dissociate from the metal center under catalytic conditions, which establishes the thiourea 1-based palladium complexes as effective catalysts for the palladium-catalyzed cross-coupling reactions.
- Mingji, Dai,Liang, Bo,Wang, Cuihua,You, Zejin,Xiang, Jing,Dong, Guangbin,Chen, Jiahua,Yang, Zhen
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p. 1669 - 1673
(2007/10/03)
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