- Organocatalytic synthesis of (Het)biaryl scaffoldsviaphotoinduced intra/intermolecular C(sp2)-H arylation by 2-pyridone derivatives
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A uniqueN,O-bidentate ligand 6-oxo-1,6-dihydro-pyridone-2-carboxylic acid dimethylamide (L1) catalyzed direct C(sp2)-H (intra/intermolecular) arylation of unactivated arenes has been developed to expedite access to (Het)biaryl scaffolds under UV-irradiation at room temperature. The protocol tolerated diverse functional groups and substitution patterns, affording the target products in moderate to excellent yields. Mechanistic investigations were also carried out to better understand the reaction pathway. Furthermore, the synthetic applicability of this unified approach has been showcasedviathe construction of biologically relevant 4-quinolone, tricyclic lactam and sultam derivatives.
- Das, Tapas Kumar,Kundu, Mrinalkanti,Mondal, Biswajit,Ghosh, Prasanjit,Das, Sajal
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p. 208 - 218
(2021/12/29)
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- Tunable Second-Level Room-Temperature Phosphorescence of Solid Supramolecules between Acrylamide–Phenylpyridium Copolymers and Cucurbit[7]uril
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A series of solid supramolecules based on acrylamide–phenylpyridium copolymers with various substituent groups (P?R: R=?CN, ?CO2Et, ?Me, ?CF3) and cucurbit[7]uril (CB[7]) are constructed to exhibit tunable second-level (from 0.9 s to
- Xu, Wen-Wen,Chen, Yong,Lu, Yi-Lin,Qin, Yue-Xiu,Zhang, Hui,Xu, Xiufang,Liu, Yu
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supporting information
(2021/12/24)
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- Palladium-Catalyzed Electrophilic Functionalization of Pyridine Derivatives through Phosphonium Salts
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Herein, we report a highly efficient and practical method for pyridine-derived heterobiaryl synthesis through palladium-catalyzed electrophilic functionalization of easily available pyridine-derived quaternary phosphonium salts. The nice generality of this reaction was goes beyond arylation, enabling facile incorporation of diverse carbon-based fragments, including alkenyl, alkynyl, and also allyl fragments, onto the pyridine core. Notably, the silver salt additive is revealed to be of vital importance for the success of this transformation and its pivotal role as transmetallation mediator, which guarantees a smooth transfer of pyridyl group to palladium intermediate, is also described.
- Che, Yuan-Yuan,Deng, Xuezu,Feng, Chao,Lin, Ling-Zhi,Pei, Bingbing,Yue, Yanni
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supporting information
p. 16414 - 16419
(2020/07/20)
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- Pyridine sulfinates as general nucleophilic coupling partners in palladium-catalyzed cross-coupling reactions with aryl halides
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Pyridine rings are ubiquitous in drug molecules; however, the pre-eminent reaction used to form carbon-carbon bonds in the pharmaceutical industry, the Suzuki-Miyaura cross-coupling reaction, often fails when applied to these structures. This phenomenon is most pronounced in 2-substituted pyridines, and results from the difficulty in preparing, the poor stability of, and low efficiency in reactions of pyridine-2-boronates. We demonstrate that by replacing these boronates with pyridine-2-sulfinates, a cross-coupling process of unrivalled scope and utility is realized. The corresponding 3-And 4-substituted pyridine variants are also efficient coupling partners. In addition, we apply these sulfinates in a library format to the preparation of medicinally relevant derivatives of the drugs varenicline (Chantix) and mepyramine (Anthisan).
- Markovic, Tim,Rocke, Benjamin N.,Blakemore, David C.,Mascitti, Vincent,Willis, Michael C.
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p. 4437 - 4442
(2017/07/11)
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- Phosphonium Salts as Pseudohalides: Regioselective Nickel-Catalyzed Cross-Coupling of Complex Pyridines and Diazines
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Heterobiaryls are important pharmacophores that are challenging to prepare by traditional cross-coupling methods. An alternative approach is presented where pyridines and diazines are converted into heteroaryl phosphonium salts and coupled with aryl boronic acids. Nickel catalysts are unique for selective heteroaryl transfer, and the reaction has a broad substrate scope that includes complex pharmaceuticals. Phosphonium ions also display orthogonal reactivity in cross-couplings compared to halides, enabling chemoselective palladium- and nickel-catalyzed coupling sequences.
- Zhang, Xuan,McNally, Andrew
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p. 9833 - 9836
(2017/08/08)
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- Silver-catalyzed arylation of (hetero)arenes by oxidative decarboxylation of aromatic carboxylic acids
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A long-standing challenge in Minisci reactions is achieving the arylation of heteroarenes by oxidative decarboxylation of aromatic carboxylic acids. To address this challenge, the silver-catalyzed intermolecular Minisci reaction of aromatic carboxylic acids was developed. With an inexpensive silver salt as a catalyst, this new reaction enables a variety of aromatic carboxylic acids to undergo decarboxylative coupling with electron-deficient arenes or heteroarenes regardless of the position of the substituents on the aromatic carboxylic acid, thus eliminating the need for ortho-substituted aromatic carboxylic acids, which were a limitation of previously reported methods.
- Kan, Jian,Huang, Shijun,Lin, Jin,Zhang, Min,Su, Weiping
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supporting information
p. 2199 - 2203
(2015/02/19)
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- Palladium dichloride adduct of N,N-bis-(diphenylphosphanylmethyl)-2- aminopyridine: Synthesis, structure and catalytic performance in the decarboxylative cross-coupling of 4-picolinic acid with aryl bromide
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Reaction of PdCl2 with N,N-bis-(diphenylphosphanylmethyl)-2- aminopyridine (bdppmapy) afforded a mononuclear complex [(bdppmapy)PdCl 2] (1). Compound 1 was characterized by elemental analysis, IR, 1H, 13C and 31P NMR, electrospray ion mass spectra (ESI-MS) and X-ray single crystal crystallography. The Pd(ii) center in 1 is chelated by bdppmapy, showing a cis-square planar geometry. With the assistance of additive Cu2O, complex 1 exhibited good catalytic activity toward the decarboxylative cross-coupling reactions between 4-picolinic acid and aryl bromides. In the presence of only 2 mol% catalyst, a family of 4-aryl-pyridines could be isolated in up to 83% yield.
- He, Run-Tian,Wang, Jian-Feng,Wang, Hui-Fang,Ren, Zhi-Gang,Lang, Jian-Ping
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p. 9786 - 9794
(2014/06/23)
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- Metal-free arylation of benzene and pyridine promoted by amino-linked nitrogen heterocyclic carbenes
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An amino-linked nitrogen heterocyclic carbene (amino-NHC), 1-tBu, has been shown to mediate carbon-carbon coupling through the direct C-H functionalization of benzene and pyridine in the absence of a metal catalyst. Using EPR, the first spectroscopic evidence corroborating the single electron transfer mechanism for the metal-free carbon-carbon coupling manifold, as reported by others, is introduced.
- Chen, Wen-Ching,Hsu, Yu-Chen,Shih, Wei-Chun,Lee, Ching-Yu,Chuang, Wen-Han,Tsai, Yi-Fang,Chen, Peter Ping-Yu,Ong, Tiow-Gan
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supporting information; experimental part
p. 6702 - 6704
(2012/07/14)
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- HETEROCYCLIC COMPOUNDS FOR THE INHIBITION OF PASK
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Disclosed herein are new heterocyclic compounds and compositions and their application as pharmaceuticals for the treatment of disease. Methods of inhibiting PAS Kinase (PASK) activity in a human or animal subject are also provided for the treatment of diseases such as diabetes mellitus.
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- Vesicular monoamine transporter substrate/inhibitor activity of MPTP/MPP+ derivatives: A structure-activity study
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The active metabolite of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), N-methyl-4-phenylpyridinium (MPP+), selectively destroys the dopaminergic neurons and induces the symptoms of Parkinson's disease. Inhibition of mitochondrial complex
- Wimalasena, D. Shyamali,Perera, Rohan P.,Heyen, Bruce J.,Balasooriya, Inoka S.,Wimalasena, Kandatege
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p. 760 - 768
(2008/09/19)
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- Microwave-assisted Suzuki coupling reactions with an encapsulated palladium catalyst for batch and continuous-flow transformations
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This article describes the design, optimisation and development of a Suzuki cross-coupling protocol mediated by an efficient palladium-en-capsulated catalyst (Pd EnCat) under microwave irradiation. The methodology has been used in both batch mode for classical library preparation and in continuous-flow applications furnishing multigram quantities of material. Described is a method that uses direct focused microwave heating whilst applying an external cooling source. This enables a lower than normal bulk temperature to be maintained throughout the reaction period leading to significant improvements in the overall yield and purity of the reaction products. Additional aspects of this novel heating protocol are discussed in relation to the prolonged lifetime and enhanced reactivity of the immobilised catalyst system.
- Baxendale, Ian R.,Griffiths-Jones, Charlotte M.,Ley, Steven V.,Tranmer, Geoffrey K.
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p. 4407 - 4416
(2008/02/07)
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- Vanilloid receptor ligands and their use in treatments
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Compounds having the general structure and compositions containing them, for the treatment of acute, inflammatory and neuropathic pain, dental pain, general headache, migraine, cluster headache, mixed-vascular and non-vascular syndromes, tension headache, general inflammation, arthritis, rheumatic diseases, osteoarthritis, inflammatory bowel disorders, inflammatory eye disorders, inflammatory or unstable bladder disorders, psoriasis, skin complaints with inflammatory components, chronic inflammatory conditions, inflammatory pain and associated hyperalgesia and allodynia, neuropathic pain and associated hyperalgesia and allodynia, diabetic neuropathy pain, causalgia, sympathetically maintained pain, deafferentation syndromes, asthma, epithelial tissue damage or dysfunction, herpes simplex, disturbances of visceral motility at respiratory, genitourinary, gastrointestinal or vascular regions, wounds, burns, allergic skin reactions, pruritis, vitiligo, general gastrointestinal disorders, gastric ulceration, duodenal ulcers, diarrhea, gastric lesions induced by necrotising agents, hair growth, vasomotor or allergic rhinitis, bronchial disorders or bladder disorders.
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- Synthesis of functionalized 4-phenyl-pyridines via electrochemically prepared organozinc reagents
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The efficient and convenient synthesis of various functionalized 4-phenyl-pyridines 2 is described. The key step of the procedure is the electrochemical formation of aromatic organozinc reagents 1 and their coupling with pyridinium salts. Intermediate 1,4
- Gall, Erwan Le,Gosmini, Corinne,Nédélec, Jean-Yves,Périchon, Jacques
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p. 1923 - 1927
(2007/10/03)
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- The palladium catalysed Suzuki coupling of 2- and 4-chloropyridines
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The Suzuki coupling of 2- and 4-chloropyridines with arylboronic acids is successfully performed under Pd(PPh3)4 catalysis. Moderate to good yields are obtained with 4-chloropyridines while 2-chloropyridines give excellent yields. The corresponding pyridine N-oxides react in the same manner. An easy and cheap access to arylpyridines, a class of compound with medicinal interest, is thus achieved.
- Lohse, Olivier,Thevenin, Philippe,Waldvogel, Erwin
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