- One-pot synthesis of xanthones and thioxanthones by the tandem coupling-cyclization of arynes and salicylates
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(Chemical Equation Presented) The reaction of silylaryl triflates, CsF, and salicylates affords a general and efficient way to prepare biologically interesting xanthones and thioxanthones. This chemistry presumably proceeds by a tandem intermolecular nucleophilic coupling and subsequent intramolecular electrophilic cyclization.
- Zhao, Jian,Larock, Richard C.
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Read Online
- Ligand-free Cu(ii)-catalyzed aerobic etherification of aryl halides with silanes: An experimental and theoretical approach
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Owing to their wide occurrence in nature and immense applications in various fields, the synthesis of aryl alkyl ethers has remained a focus of interest. In contrast to the conventional/traditional methods of etherification, herein, we have reported a more efficient method, which is better yielding and more general in application. The etherification of aryl halides by alkoxy/phenoxy silanes was catalyzed by copper acetate in the presence of cesium carbonate and oxygen in DMF at 145 °C. All the as-synthesized compounds were characterized via the 1H-NMR and 13C-NMR spectroscopic techniques. Density functional theory calculations using the B3LYP functional were performed to elucidate the reaction mechanism. The C-O coupling reaction between 2-nitroiodobenzene and tetramethoxysilane was used as a model reaction. The activation energy barriers for the generation of catalytic species (31.6 kcal mol-1) and the σ-bond metathesis (16.0 kcal mol-1), oxidative addition/reductive elimination (20.3 kcal mol-1), halogen atom transfer (19.2 kcal mol-1) and single electron transfer (SET) (29.5 kcal mol-1) mechanisms for the C-O coupling reaction were calculated. Calculations for the key reaction steps were repeated with the B3PW91, PBEH1PBE, wB97XD, CAM-B3LYP and mPW1LYP functionals. The formation of catalytic species via a single electron transfer reaction between tetramethoxysilane and copper acetate, formation of methoxy radicals and methoxylation of copper showed an overall energy barrier of 31.6 kcal mol-1, and therefore is the rate determining step.
- Ahmed, Muhammad Naeem,Ahmad, Khalil,Yasin, Khawaja Ansar,Farooq, Tayyaba,Khan, Bilal Ahmad,Roy, Soumendra K.
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p. 11316 - 11333
(2019/07/31)
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- Concise synthesis of xanthones by the tandem etherification—Acylation of diaryliodonium salts with salicylates
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An efficient synthetic method for multi-substituted xanthones was developed. The reaction of diaryliodonium salts and salicylates was employed for the preparation of the xanthones. This method proceeded through an intermolecular etherification-acylation t
- Liu, Gaoxiaozheng,Wu, Chao,Chen, Bifeng,He, Ru,Chen, Chao
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p. 985 - 988
(2018/04/05)
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- Decarbonylative Methylation of Aromatic Esters by a Nickel Catalyst
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A Ni-catalyzed decarbonylative methylation of aromatic esters was achieved using methylaluminums as methylating agents. Dimethylaluminum chlorides uniquely worked as the methyl source. Because of the Lewis acidity of aluminum reagents, less reactive alkyl esters could also undergo the present methylation. By controlling the Lewis acidity of aluminum reagents, a chemoselective decarbonylative cross-coupling between alkyl esters and phenyl esters was successful.
- Okita, Toshimasa,Muto, Kei,Yamaguchi, Junichiro
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supporting information
p. 3132 - 3135
(2018/05/28)
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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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- Iodobenzene-Catalyzed Synthesis of Phenanthridinones via Oxidative C-H Amidation
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We report a novel synthesis of phenanthridinones from N-methoxybenzamides using an oxidative C-H amidation reaction at room temperature in open air with modest to excellent yields. This method demonstrated unprecedented substrate scope. In particular, it solved the long-standing challenge in the synthesis of phenanthridinones with sterically demanding substitutions.
- Liang, Dongdong,Yu, Wenbo,Nguyen, Nam,Deschamps, Jeffrey R.,Imler, Gregory H.,Li, Yue,MacKerell, Alexander D.,Jiang, Chao,Xue, Fengtian
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p. 3589 - 3596
(2017/04/11)
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- Iodine(III)-mediated construction of the dibenzoxazepinone skeleton from 2-(aryloxy)benzamides through oxidative C-N formation
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Dibenzoxazepinone compounds were conveniently synthesized from 2-(aryloxy)benzamides through hypervalent iodine(iii)-mediated oxidative cyclization under mild reaction conditions.
- Guo, Xuliang,Zhang-Negrerie, Daisy,Du, Yunfei
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p. 94732 - 94736
(2015/11/24)
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- Synthesis of new thiazolo[3,2-b][1,2,4]triazole-6(5H)-one derivatives as potent analgesic and anti-inflammatory agents
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A series of thiazolo[3,2-b][1,2,4]triazole-6(5H)-ones were synthesized and evaluated for their analgesic and anti-inflammatory activities. The structures of these compounds were supported by FT-IR, 1HNMR, and Mass spectra. All of the final comp
- Assarzadeh, Mohammad Javad,Almasirad, Ali,Shafiee, Abbas,Koopaei, Mansur Nassiri,Abdollahi, Mohammad
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p. 948 - 957
(2014/03/21)
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- Synthesis, antitubercular activity and docking study of novel cyclic azole substituted diphenyl ether derivatives
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The re-emergence of tuberculosis (TB) as a global health problem over the past few decades, accompanied by the rise of drug-resistant strains of Mycobacterium tuberculosis, emphasizes the need for discovery of new therapeutic drugs against this disease. The emerging serious problem both in terms of TB control and clinical management prompted us to synthesize a novel series of heterocyclic o/m/p substituted diphenyl ether derivatives and determine their activity against H37Rv strain of Mycobacterium. All 10 compounds inhibited the growth of the H37Rv strain of mycobacterium at concentrations as low as 1 μg/mL. This level of activity was found comparable to the reference drugs rifampicin and isoniazid at the same concentration. Molecular modeling of the binding of the diphenyl ether derivatives on enoyl-ACP reductase, the molecular target site of triclosan, indicated that these compounds fit within the binding domain occupied by triclosan. Hence the diphenyl ether derivatives tested in this study were docked to ENR and the binding of the diphenyl ether derivatives was also estimated using a variety of scoring functions that have been compiled into the single consensus score. As the scores ranged from 47.27% to 65.81%, these bioactive compounds appear to have a novel mechanism of action against M. tuberculosis, and their structural features should be studied further for their potential use as new antitubercular drugs.
- Kini, Suvarna G.,Bhat, Anilchandra R.,Bryant, Byron,Williamson, John S.,Dayan, Franck E.
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experimental part
p. 492 - 500
(2009/08/07)
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- The generation of aryl anions by double electron transfer to aryl iodides from a neutral ground-state organic super-electron donor
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(Chemical Equation Presented) It takes two to cyclize: Aryl halides are reduced to aryl anions by double electron transfer from the neutral ground-state electron donor 1 (see scheme), as shown by the formation of a cyclic ketone (2). The reduced compound (3) is also formed. Calculations show that the loss of two electrons from 1 is both thermodynamically and kinetically viable and generates a more planar resonance-stabilized structure.
- Murphy, John A.,Zhou, Sheng-Ze,Thomson, Douglas W.,Schoenebeck, Franziska,Mahesh, Mohan,Park, Stuart R.,Tuttle, Tell,Berlouis, Leonard E. A.
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p. 5178 - 5183
(2008/03/27)
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- Synthesis of xanthones, thioxanthones, and acridones by the coupling of arynes and substituted benzoates
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The reaction of silylaryl triflates, CsF, and ortho-heteroatom-substituted benzoates affords a general and efficient way to prepare biologically interesting xanthones, thioxanthones, and acridones. This chemistry presumably proceeds by a tandem intermolecular nucleophilic coupling of the benzoate with an aryne and a subsequent intramolecular electrophilic cyclization.
- Zhao, Jian,Larock, Richard C.
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p. 583 - 588
(2007/10/03)
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- Design and synthesis of 4H-3-(2-phenoxy)phenyl-1,2,4-triazole derivatives as benzodiazepine receptor agonists
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A series of new 5-substituted analogues of 4H-3-(2-phenoxy)phenyl-1,2,4-triazole and its chlorinated derivatives was designed and prepared. Conformational analysis and superimposition of energy minima conformers of the compounds on estazolam, a known benz
- Akbarzadeh, Tahmineh,Tabatabai, Sayyed A.,Khoshnoud, Mohammad J.,Shafaghi, Bijan,Shafiee, Abbas
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p. 769 - 773
(2007/10/03)
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- Imidazo heterocyclic compounds
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A novel class of imidazo heterocyclic compounds, pharmaceutical compositions comprising them and use thereof in the treatment and/or prevention of diseases and disorders related to the histamine H3 receptor. More particularly, the compounds are useful for the treatment and/or prevention of diseases and disorders in which an interaction with the histamine H3 receptor is beneficial.
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