- Copper and triphenylphosphine-promoted sulfenylation of quinones with arylsulfonyl chlorides
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The efficient copper and triphenylphosphine-promoted sulfenylation of quinones with arylsulfonyl chlorides has been developed under mild conditions with moderate to good yields. Significantly, this provides an alternative method to synthesise arylthioquinone derivatives. This is the first time that arylthioquinones with arylsulfonyl chlorides as starting material have been prepared, which avoids the use of the awful smelling thioalcohols and thiophenols.
- Yu, Xiaoli,Wu, Qiujin,Wan, Huida,Xu, Zhaojun,Xu, Xingle,Wang, Dawei
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Read Online
- Oxidative radical coupling of hydroquinones and thiols using chromic acid: One-pot synthesis of quinonyl alkyl/aryl thioethers
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An efficient, simple and practical protocol for one-pot sequential oxidative radical C-H/S-H cross-coupling of thiols with hydroquinones (HQs) and oxidation leading to the formation of quinonyl alkyl/aryl thioethers using H2CrO4was developed. This cross-coupling of thiyl and aryl radicals offers mono thioethers in good to moderate yield and works well with a wide variety of thiols. Similarly, this method works well for coupling of 2-amino thiophenol and HQs to form phenothiazine-3-ones5a-c. C-S bond formationviathioether synthesis was observed using a chromium reagent for the first time. Theoretical studies on the pharmacokinetic properties of compounds5a-crevealed that due to drug-like properties, compound5bstrongly binds with Alzheimer's disease (AD) associated AChE target sites.
- Adarsh Krishna, T. P.,Chinnasamy, Suresh,Ilangovan, Andivelu,Pandaram, Sakthivel
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p. 19454 - 19462
(2020/06/04)
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- The convenient synthesis and reaction of 2-(arylthio)phenols under ligand-free conditions: arylthioquinone preparation through cascade C–H functionalization and oxidation from arylthiols and aryl iodides
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A convenient and simple method for copper-catalyzed synthesis of 2-(arylthio)phenols through C–H functionalization of arylthiols and aryl iodides was developed under ligand-free conditions without nitrogen protection. In addition, arylthioquinone derivatives were very easily prepared for one more step of oxidation with moderate to good yields. This provide an alternative and efficient way to 2-(arylthio)phenols and arylthioquinone derivatives smoothly without using ligands and nitrogen protection or expensive arylboronic acids.
- Wang, Dawei,Yu, Xiaoli,Wang, Likui,Yao, Wei,Xu, Zhaojun,Wan, Huida
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p. 5211 - 5214
(2016/11/13)
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- Copper-Catalyzed Reaction Cascade of Thiophenol Hydroxylation and S-Arylation through Disulfide-Directed C-H Activation
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Copper-catalyzed thiophenol C-H activation is described. Through an initial attempt to conduct C-arylation with arylboronic acid, a rather surprising sequential C-H activation and S-arylation was discovered. Mechanistic investigation revealed the disulfide intermediate as the key component in directing C-H oxidation. The overall reaction proceeded under mild conditions with molecular oxygen as the oxidant. Discovery of disulfide as the directing group provides a potential new direction for catalytic C-H functionalization under mild conditions.
- Wang, Dawei,Yu, Xin,Yao, Wei,Hu, Wenkang,Ge, Chenyang,Shi, Xiaodong
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supporting information
p. 5543 - 5546
(2016/04/20)
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- 'On water': unprecedented nucleophilic substitution and addition reactions with 1,4-quinones in aqueous suspension
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Unique nucleophilic substitution and addition reactions of 1,4-quinones in aqueous suspension with aromatic amines, primary aliphatic amines, amino acid, ester of amino acid, heterocyclic amines, hydrazine, amide, and thioethers are described in absence o
- Tandon, Vishnu K.,Maurya, Hardesh K.
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experimental part
p. 5896 - 5902
(2010/01/11)
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- NEUROPROTECTIVE BENZO[1,3]OXATHOL-2-ONES
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This invention relates to benzo[1,3]oxathiol-2-ones, derivatives, and precursors thereof, and their use as neuroprotective agents in the treatment and prevention of neuronal disorders of the central and peripheral nervous systems.
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Page/Page column 25-26
(2010/02/10)
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- Polymer-supported hypervalent iodine reagents in 'clean' organic synthesis with potential application in combinatorial chemistry
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A clean oxidation reaction of a variety of substrates using polymer-supported (diacetoxyiodo)benzene (PSDIB) which proceeds in high to excellent yield with maximum purity is described including isolation and regeneration of the polymer reagent.
- Ley, Steven V.,Thomas, Andrew W.,Finch, Harry
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p. 669 - 671
(2007/10/03)
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- Aerobic oxidation of hydroquinones to quinones catalyzed by VO(acac)2
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In the presence of a catalytic amount of VO(acac)2, oxidation of hydroquinone and its derivatives with molecular oxygen at room temperature gave the corresponding quinones in moderate to high yields.
- Hwang, Der-Ren,Chu, Chang-Ying,Wang, Sheng-Kai,Uang, Biing-Jiun
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- Persulfate/copper(II): A mild and efficient oxidising system for the conversion of dihydroxybenzenes to quinones
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Sodium persulfate in the presence of copper(II) ions efficiently oxidises a number of o- and p-diphenols to the corresponding quinones under mild conditions.
- Costantini,D'Ischia,Prota
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p. 1399 - 1400
(2007/10/02)
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- Use of Sulfoxides as Cocatalysts in the Palladium-Quinone-Catalyzed 1,4-Diacetoxylation of 1,3-Dienes. An Example of Ligand-Accelerated Catalysis
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The use of sulfinyl quinones as cocatalysts in the palladium-catalyzed 1,4-diacetoxylation of 1,3-dienes improves the stereochemical outcome of the reaction by increasing the rate of the internal migration of the acetate nucleophile.A mechansim of the int
- Grennberg, Helena,Gogoll, Adolf,Baeckwall, Jan-E.
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p. 5808 - 5811
(2007/10/02)
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- Synthesis of the cis-3a,8b-Dihydrofurobenzofuran-2(3H)-one Ring System via a Furofuran Annulation to Activated Benzoquinones
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The uncatalysed addition of 2-(trimethylsiloxy)furan (4) to the 1,4-benzoquinones (5a-e) containing electron-withdrawing groups at C-2 gave the cis-3a,8b-dihydrofurobenzofuran-2(3H)-ones (6a-e) in 51-76percent yields.The 1,4-benzoquinones (5f, g, h) without electron-withdrawing groups at C-2 failed to undergo the furofuran annulation, with none of the desired adducts (6f, g, h) being isolated.The carboxylic acid adduct (6i; R=CO2H) was prepared indirectly by reductive hydrolysis of either the phenacyl adduct (6e) or the trichloroethyl ester adduct (6d) using zinc in acetic acid (9).Treatment of the methyl ketone adduct (6b) with acid effected a ring opening to the corresponding (benzofuran-2-yl)acetic acid.
- Brimble, Margaret A.,Brimble, Mark T.,Gibson, Jennifer J.
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p. 179 - 184
(2007/10/02)
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- Lewis Acid Catalyzed Cycloreversion Reaction of Strained Cage Ketones to Triquinane Skeletons: Kinetic Evidence for a Large Acceleration of the Reaction Owing to Stereoelectronic Requirement
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Cookson's pentacyclic cage diketones substituted with an electron-donating group (1b-e) underwent a remarkably fast cycloreversion reaction under various Lewis acid catalyzed conditions.The high reactivity of these cage ketones is discussed in terms of push-pull type interactions on the basis of large substituent effects and kinetic measurements.Keywords - cycloreversion reaction; Cookson's pentacyclic cage diketone; Lewis acid catalyst; electron-donating group; stereoelectronic effect
- Okamoto, Yasushi,Senokuchi, Kazuhiko,Kanematsu, Ken
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p. 4593 - 4599
(2007/10/02)
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