- Catalytic Synthesis of 1 H-2-Benzoxocins: Cobalt(III)-Carbene Radical Approach to 8-Membered Heterocyclic Enol Ethers
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The metallo-radical activation of ortho-allylcarbonyl-aryl N-arylsulfonylhydrazones with the paramagnetic cobalt(II) porphyrin catalyst [CoII(TPP)] (TPP = tetraphenylporphyrin) provides an efficient and powerful method for the synthesis of novel 8-membered heterocyclic enol ethers. The synthetic protocol is versatile and practical and enables the synthesis of a wide range of unique 1H-2-benzoxocins in high yields. The catalytic cyclization reactions proceed with excellent chemoselectivities, have a high functional group tolerance, and provide several opportunities for the synthesis of new bioactive compounds. The reactions are shown to proceed via cobalt(III)-carbene radical intermediates, which are involved in intramolecular hydrogen transfer (HAT) from the allylic position to the carbene radical, followed by a near-barrierless radical rebound step in the coordination sphere of cobalt. The proposed mechanism is supported by experimental observations, density functional theory (DFT) calculations, and spin trapping experiments.
- De Bruin, Bas,De Zwart, Felix J.,Li, Zirui,Mathew, Simon,Wolzak, Lukas A.,Zhou, Minghui
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p. 20501 - 20512
(2021/12/03)
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- Chiral Hydroxytetraphenylene-Catalyzed Asymmetric Conjugate Addition of Boronic Acids to Enones
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(S)-2,15-Br2-DHTP-catalyzed asymmetric conjugate addition of boronic acids to β-trifluoromethyl α,β-unsaturated ketones and enones was studied. The reaction afforded the corresponding Michael addition products in moderate to high yields with excellent enantioselectivities (up to 99:1 er). This catalytic system features mild reaction conditions, high efficiency, and tolerance to heteroarylboronic acids.
- Chai, Guo-Li,Sun, A-Qiang,Zhai, Dong,Wang, Juan,Deng, Wei-Qiao,Wong, Henry N.C.,Chang, Junbiao
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supporting information
p. 5040 - 5045
(2019/07/03)
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- A robust multifunctional ligand-controlled palladium-catalyzed carbonylation reaction in water
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A novel, hydrophilic and recyclable methoxypolyethylene glycol (PEG)-modulated s-triazine-based multifunctional Schiff base/N,P-ligand L9 was prepared and used in Pd-catalyzed Heck-type carbonylative coupling reactions, affording diverse chalcone derivatives and 1,4-dicarbonyl esters in good yields.
- Gao, Pei-Sen,Zhang, Kan,Yang, Ming-Ming,Xu, Shan,Sun, Hua-Ming,Zhang, Jin-Lei,Gao, Zi-Wei,Zhang, Wei-Qiang,Xu, Li-Wen
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supporting information
p. 5074 - 5077
(2018/05/26)
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- Synthesis of 1,5-benzodiazepine derivatives using p-toluenesulfonic acid as catalyst
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A series of substituted ethyl 4-oxo-4-phenylbut-2-enoates were prepared and reacted with substituted o-phenylenediamine, undergone Michael addition reactions and cyclodehydration to provide novel 4-phenyl-2,3-dihydro-1,5-benzodiazepine-2-carboxylate derivatives with excellent yields. The synthetic protocol fulfilled many green-chemical requirements by using simple catalyst p-toluenesulfonic acid as activator and ethanol as solvent at room temperature.
- Wang, Shasha,Hu, Lijuan,Cheng, Suyan,Wang, Lanzhi
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p. 419 - 424
(2015/01/30)
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- Flow chemistry synthesis of zolpidem, alpidem and other GABAA agonists and their biological evaluation through the use of in-line frontal affinity chromatography
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The flow of information between chemical and biological research can present a bottleneck in pharmaceutical research. Tools that bridge these disciplines and aid information exchange have therefore clear value. Over the last few years, both synthetic chemistry and biological screening have benefited from automation, and a seamless chemistry-biology interface is now possible. We report here on the use of flow processes to perform synthesis and biological evaluation in an integrated manner. As proof of concept, a flow synthesis of a series of imidazo[1,2-a]pyridines, including zolpidem and alpidem, was developed and connected to a Frontal Affinity Chromatography screening assay to investigate their interaction with Human Serum Albumin (HSA). The Royal Society of Chemistry 2013.
- Guetzoyan, Lucie,Nikbin, Nikzad,Baxendale, Ian R.,Ley, Steven V.
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p. 764 - 769
(2013/03/14)
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- Structure-activity relationship, cytotoxicity and mode of action of 2-ester-substituted 1,5-benzothiazepines as potent antifungal agents
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Our studies examined the structural features responsible for the antifungal activity of 2-ethoxycarbonyl-1,5-benzothiazepine (7a). Three series of 1,5-benzothiazepine derivatives were synthesized and screened for their antifungal activity. The results suggested that the ethoxycarbonyl group at the 2 position and the imine moiety on the seven-membered ring are essential for activity. The most potent of the synthesized analogues (7a, 7b) were further studied by evaluating their cytotoxicity and mode of action (for 7a). The results showed that compounds 7a and 7b were relatively safe for BV2 cells, but compound 7a interfered with Cryptococcus neoformans cell wall integrity by increasing the chitinase activity. Therefore, compound 7a was considered safe as an antifungal agent for animal cells. Three series of 1,5-benzothiazepine derivatives were synthesized and their antifungal activities were evaluated to determine the structure-activity relationships with respect to the antifungal activity of 2-ester-substituted 1,5-benzothiazepines. The effective antifungal compounds 7a and 7b were further studied for their antifungal activity, cytotoxicity and mechanism of action (for compound 7a). The results provided important information about this class of benzothiazepines. Copyright
- Kang, Wang,Du, Xingqiong,Wang, Lanzhi,Hu, Lijuan,Dong, Yuhuan,Bian, Yanqing,Li, Yuan
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p. 1305 - 1314
(2013/11/06)
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- Catalytic oxidations of enolizable ketones using 2-alkylidene-4- oxothiazolidine vinyl bromide
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Direct oxidation of enolizable ketones to α-hydroxy derivatives, vicinal dicarbonyls or tricarbonyl compounds has been achieved by a catalytic amount of 2-alkylidene-4-oxothiazolidine vinyl bromide in DMSO as a solvent. The yields range from moderate to good.
- Baranac-Stojanovi?, Marija,Markovi?, Rade,Stojanovi?, Milovan
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experimental part
p. 8000 - 8008
(2011/11/06)
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- Efficient oxidation-Wittig olefination-Diels-Alder multicomponent reactions of α-hydroxyketones
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α-Hydroxyketones undergo efficient tandem oxidation-Wittig olefination reactions in the presence of an oxidant to produce high yields of γ-ketocrotonate products. On carrying out the oxidation-Wittig olefination reaction in the presence of 2,3-dimethyl-1,3-butadiene, a novel multicomponent reaction sequence provides access to cycloadducts in high yield.
- Harris, Geraint H.,Graham, Andrew E.
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experimental part
p. 6890 - 6892
(2011/03/18)
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- The synthesis and application of 3,6-bis(triphenylphosphonium) cyclohexene dichromate: An efficient oxidizing agent
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The synthesis of 3,6-bis(triphenylphosphonium) cyclohexene dichromate is described. This reagent oxidizes primary and secondary alcohols to their corresponding carbonyl compounds thiols to disulfides, and amines to their azo compounds. Copyright Taylor & Francis Group, LLC.
- Badri, Rashid,Mostoufi, Azar
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p. 1513 - 1519
(2007/10/03)
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- Selective oxidation of benzylic substrates to their corresponding carbonyl compounds with 3,6-Bis(triphenylphosphonium)cyclohexene peroxodisulfate
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3,6-Bis(triphenylphosphonium)cyclohexene peroxodisulfate (BTPCP) was found to be a highly effective and selective oxidant for the conversion of benzyl monohalides, nitrils, and amines to their corresponding carbonyl compounds under mild and neutral conditions.
- Badri, Rashid,Soleymani, Mousa
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p. 1325 - 1332
(2007/10/03)
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- 3,6-bis(triphenylphosphonium) cyclohexene peroxodisulfate as an efficient and mild oxidizing agent for conversion of alkylbenzenes to corresponding carbonyl compounds
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Oxidation of a series of alkylbenzenes by BTPCP under neutral conditions to corresponding carbonyl compounds is described.
- Badri, Rashid,Soleymani, Mousa
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p. 2385 - 2389
(2007/10/03)
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- NAD(P)H MODELS 20 CHEMOSELECTIVE METAL ION CATALYZED REDUCTION OF α-KETO-β,γ-UNSATURATED ESTERS BY 1,4-DIHYDROPYRIDINE DERIVATIVES
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Ethyl 2-oxo-4-aryl-3-butene-1-oates (1a-c) are reduced by NAD(P)H models (1-n-propyl-1,4-dihydronicotinamide (4) and Hantzsch ester (5)), in presence of magnesium perchlorate.One equivalent of the reductant reduces the substrates selectively to the corresponding 2-oxo-4-arylbutanoates (6, 10a, b).An additional equivalent and higher temperature, converts ethyl 2-oxo-4-phenylbutanoate (6) to ethyl 2-hydroxy-4-phenylbutanoate (7).Reduction of ethyl 2-oxo-4-phenyl-3-buten-1-oate (1a) by Hantzsch ester in C2H5OD or by Hantzsch ester-4,4-d2 in C2H5OH, leads to direct transfer of the hydrogen or deuterium, respectively, without isotopic scrambling.These results have been interpreted to support the hydride transfer mechanism.
- Meijer, Louis H. P.,Pandit, Upendra K.
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p. 467 - 472
(2007/10/02)
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- SYNTHESIS AND SOME TRANSFORMATIONS OF VINYL β-ACETYL- AND β-BENZOYLACRYLATES
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Vinyl β-acetyl- and β-benzoylacrylates were obtained by transvinylation with vinyl acetate in the presence of the catalyst Hg(OCOCH3)2.BF3.O(C2H5)2.It was shown that the reactions with bromine, mercuric acetates, and butyl hydrosulfide at the vinyloxy group are regioselective.
- Komarova, L. I.,Zhuravlev, S. V.,Sal'nikova, L. V.
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p. 1422 - 1425
(2007/10/02)
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