- Para-Selective C-H Borylation of Common Arene Building Blocks Enabled by Ion-Pairing with a Bulky Countercation
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The selective functionalization of C-H bonds at the arene para position is highly challenging using transition metal catalysis. Iridium-catalyzed borylation has emerged as a leading technique for arene functionalization, but there are only a handful of strategies for para-selective borylation, which operate on specific substrate classes and use bespoke ligands or catalysts. We describe a remarkably general protocol which results in para-selectivity on some of the most common arene building blocks (anilines, benzylamines, phenols, benzyl alcohols) and uses standard borylation ligands. Our strategy hinges upon the facile conversion of the substrates into sulfate or sulfamate salts, wherein the anionic arene component is paired with a tetrabutylammonium cation. We hypothesize that the bulk of this cation disfavors meta-C-H borylation, thereby promoting the challenging para-selective reaction.
- Mihai, Madalina T.,Williams, Benjamin D.,Phipps, Robert J.
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p. 15477 - 15482
(2019/10/11)
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- Photocatalytic Radical Alkylation of Electrophilic Olefins by Benzylic and Alkylic Zinc-Sulfinates
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Alkyl radicals are obtained by photocatalytic oxidation of readily prepared or commercially available zinc sulfinates. The convenient benzylation and alkylation of a variety of electron-poor olefins triggered by the iridium(III) complex 6 Ir[dF(CF3)ppy]2(dtbbpy)PF6 as photocatalyst is described. Moreover, it is shown that zinc sulfinates can be used for facile nonradical sulfonylation reactions with highly electrophilic Michael acceptors.
- Gualandi, Andrea,Mazzarella, Daniele,Ortega-Martínez, Aitor,Mengozzi, Luca,Calcinelli, Fabio,Matteucci, Elia,Monti, Filippo,Armaroli, Nicola,Sambri, Letizia,Cozzi, Pier Giorgio
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p. 5357 - 5362
(2017/08/17)
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- Rhodium-Catalyzed meta-C?H Functionalization of Arenes
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Rhodium-catalyzed ortho-C?H functionalization is well known in the literature. Described herein is the Xphos-supported rhodium catalysis of meta-C?H olefination of benzylsulfonic acid and phenyl acetic acid frameworks with the assistance of a para-methoxy-substituted cyano phenol as the directing group. Complete mono-selectivity is observed for both scaffolds. A wide range of olefins and functional groups attached to arene are tolerated in this protocol.
- Bera, Milan,Agasti, Soumitra,Chowdhury, Rajdip,Mondal, Rahul,Pal, Debasis,Maiti, Debabrata
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supporting information
p. 5272 - 5276
(2017/04/27)
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- Palladium-Catalyzed Remote meta-Selective C-H Bond Silylation and Germanylation
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Selective meta-C-H activation of arenes to date has met with a limited number of functionalizations. Expanding the horizon of meta-C-H functionalization, herein we disclose an unprecedented meta-silylation and -germanylation protocol by employing a simple nitrile-based directing template. Longer linkers between the target site and the directing template were successfully explored for meta-silylation (sp2-? and sp2-ζ). Additionally, synthetic utility was demonstrated with several postsynthetic elaborations and with a formal synthesis of TAC101, a promising drug for the treatment of lung cancer.
- Modak, Atanu,Patra, Tuhin,Chowdhury, Rajdip,Raul, Suman,Maiti, Debabrata
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supporting information
p. 2418 - 2423
(2017/07/17)
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- Palladium(II)-Catalyzed meta-C-H Olefination: Constructing Multisubstituted Arenes through Homo-Diolefination and Sequential Hetero-Diolefination
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Divinylbenzene derivatives represent an important class of molecular building blocks in organic chemistry and materials science. Reported herein is the palladium-catalyzed synthesis of divinylbenzenes by meta-C-H olefination of sulfone-based arenes. Successful sequential olefinations in a position-selective manner provided a novel route for the synthesis of hetero-dialkenylated products, which are difficult to access using conventional methods. Additionally, 1,3,5-trialkenylated compounds can be generated upon successful removal of the directing group. Jockeying for position: Reported herein is the palladium-catalyzed synthesis of mono- and divinylbenzenes by meta-C-H olefination of benzyl sulfones. Successful sequential olefinations in a position-selective manner provided a novel route for the synthesis of hetero-dialkenylated products, which are difficult to access using conventional methods. DG=directing group.
- Bera, Milan,Maji, Arun,Sahoo, Santosh K.,Maiti, Debabrata
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supporting information
p. 8515 - 8519
(2015/11/27)
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- Tert -Butyl Hypochlorite Mediated Oxidative Chlorination of S -Alkylisothiourea Salts: Synthesis of Sulfonyl Chlorides
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Under neutral conditions, a variety of S-alkylisothiourea salts were smoothly converted into the corresponding sulfonyl chlorides through tert-butyl chlorite mediated oxidative chlorination in good to excellent yields after simple purification. In addition to the environmental and procedural advantages of this method, the neutral conditions potentially make it applicable to substrates that bear acid-sensitive functional groups. For example, the Cbz-protected 2-aminoethanesulfonyl chloride could be synthesized in moderate to good yields under the current neutral conditions, and the acid-sensitive Cbz-protecting group was not affected.
- Qiu, Kui,Wang, Rennan
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p. 3186 - 3190
(2015/10/19)
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- Convenient and environment-friendly synthesis of sulfonyl chlorides from S -alkylisothiourea salts via N-chlorosuccinimide chlorosulfonation
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A convenient, practical, and environmentally friendly method for the synthesis of sulfonyl chlorides has been developed. Structurally diverse sulfonyl chlorides were synthesized in moderate to excellent yields from S-alkylisothiourea salts, which can be easily prepared from readily accessible alkyl halides or mesylates and inexpensive thiourea, via N-chlorosuccinimide chlorosulfonation. In large-scale syntheses, the byproduct succinimide from 'waste water' can be conveniently converted into the starting reagent N-chlorosuccinimide with sodium hypochlorite (bleach) to make the method sustainable. Georg Thieme Verlag Stuttgart, New York.
- Yang, Zhanhui,Xu, Jiaxi
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p. 1675 - 1682
(2013/07/27)
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- Simple synthesis of sulfonyl chlorides from thiol precursors and derivatives by NaClO2-mediated oxidative chlorosulfonation
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A simple method to synthesize diverse sulfonyl chlorides through NaClO 2-mediated oxidative chlorosulfonation of S-alkyl isothiourea salts is presented. The approach features safe operation, environmental friendliness, convenient purification procedures, and delivers high yields of up to 96%. The procedure is also applicable to substrates such as thiols, disulfides, thioacetates, and xanthates. It is a versatile and convenient method for the synthesis of various sulfonyl chlorides from different thiol precursors and derivatives. Georg Thieme Verlag Stuttgart, New York.
- Yang, Zhanhui,Zheng, Yongpeng,Xu, Jiaxi
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p. 2165 - 2169
(2013/10/22)
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- Access to a wide range of sultams by cyclodialkylation of α-substituted methanesulfonanilides
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A wide range of five- and six-membered sultams bearing an α-ethoxycarbonyl-α-methyl substituent or an α-aryl group (17 examples) were synthesized by the cyclodialkylation of α-substituted methanesulfonanilides with α,ω-dihaloalkanes in the presence of K2CO3 or under phase-transfer catalysis (PTC) conditions. Upon treatment with K2CO3 in N,N-dimethylformamide (DMF) or NaH in dimethyl sulfoxide (DMSO), N-(2,3-dibromopropyl)-α- toluenesulfonanilides furnished different 1,3-diaryl-2-thia-3-azabicyclo[3.1.0] hexane 2,2-dioxides in good to excellent yields (51-88 %, 16 examples). The 4-methoxyphenyl (PMP) group was easily removed from the sultam nitrogen atom by treatment of the corresponding bicyclic sultams with cerium(IV) ammonium nitrate in acetonitrile (71-84 % yield, 6 examples). The intermolecular cyclodialkylation of α-substituted methanesulfonamides constitutes a simple and efficient route to five- and six-membered sultams with α-ethoxycarbonyl-α-methyl or α-aryl substitution. The intramolecular cyclodialkylation of N-(2,3-dibromopropyl)-α- toluenesulfanilides readily leads to bicyclic sultams bearing a cyclopropane ring. Copyright
- Rassadin, Valentin A.,Grosheva, Daria S.,Arefeva, Irina A.,Tomashevskiy, Aleksandr A.,Sokolov, Victor V.,De Meijere, Armin
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supporting information
p. 5028 - 5037,10
(2020/08/24)
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- Methods for the use of inhibitors of cytosolic phospholipase A2 in the treatment of thrombosis
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This invention provides methods for the use of substituted indole compounds of the general formula: and pharmaceutically acceptable salt forms thereof. The invention provides methods for the use of the compounds in the treating or preventing thrombosis in a mammal, or preventing progression of symptoms of thrombosis.
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Page/Page column 22
(2010/11/29)
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- N-1H-Benzimidazol-5-ylbenzenesulfonamide derivatives as potent hPXR agonists
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The Human Pregnane X Receptor (hPXR) is a nuclear receptor that regulates the expression of phase I and phase II drug-metabolizing enzymes, as well as that of drug transporters. Because this receptor plays a critical role in protecting tissues from potentially toxic endo- and xenobiotics, highly active agonists could represent novel therapeutic tools in treating several human diseases. Using an in vitro screening reporter system that allow to characterize hPXR activators and a first step of chemical modifications of an original agonist ligand (C2BA-4, 1-(2-chlorophenyl)-N-[1-(1-phenylethyl)-1H-benzimidazol-5-yl]methanesulf onamide), we identified compounds with a N-1H-benzimidazol-5-ylbenzenesulfonamide scaffold as a potent family of hPXR agonists. Further chemical modifications allowed us to identify enhanced activators, notably N-(1-benzyl-1H-benzimidazol-5-yl)-2,3,4,5,6-pentamethylbenzenesulfonamid e (6n) with an EC50 value in the subnanomolar range. Accordingly to their potent EC50, these compounds induced an efficient protection of hPXR against proteolytic digestion by trypsin even at very low ligand concentrations and were able to induce the expression of the main target genes of hPXR, CYP3A4 and CYP2B6, in primary cultures of human hepatocytes.
- Benod, Cindy,Subra, Guy,Nahoum, Virginie,Mallavialle, Aude,Guichou, Jean-Francois,Milhau, Julien,Robles, Samuel,Bourguet, William,Pascussi, Jean-Marc,Balaguer, Patrick,Chavanieu, Alain
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p. 3537 - 3549
(2008/12/20)
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- Process for making an aldehyde
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A process for making an aromatic aldehyde in which a sulfoxide is reacted with a dihalogenated aromatic compound in the absence of an effective amount of an activating reagent. The aldehyde may then be used to make other compounds, such as a compound that acts as a cPLA inhibitor.
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- REACTION OF ARYLMETHANESULFONYL AND STYRYLMETHANESULFONYL CHLORIDES WITH TRIETHYLAMINE
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A series of arylmethanesulfonyl chlorides were treated with triethylamine in THF to give stilbenes in excellent yields.Workup of the mixtures below 10 deg C permits isolation of stilbene episulfones which on warming decompose to yield the corresponding stilbenes stereospecifically.Application of the reaction to 9-fluorenylsulfonyl chloride affords bifluorenylidene, while trans-styrylmethanesulfonyl chloride gives 4,5-dihydro-4,5-diphenylthiepin 1,1-dioxide and 1,6-diphenylhexatriene.
- Nakayama, Juzo,Tanuma, Mitsuru,Honda, Yoshiko,Hoshino, Masamatsu
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p. 4553 - 4556
(2007/10/02)
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- Structure-activity studies on antihyperlipidemic N-benzoylsulfamates, N-benzylsulfamates, and benzylsulfonamides
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A series of aryl substituted N-benzoyl- and N-benzylsulfamic acid sodium salts and benzylsulfonamide sodium salts have been prepared and examined for antihyperlipidemic activity in male CF1 mice at a dose level of 20 mg/kg/d ip for 16 d. These substances were also subjected to toxicological evaluation and chemical stability studies. In general, both series of sulfamates and sulfonamides significantly lowered serum cholesterol and triglyceride levels in mice. The compounds were nonmutagenic, showed no acute toxicity or impaired liver or kidney function in male mice, and were chemically stable both as the monohydrates and in aqueous solution over a pH range of 3.5-7.4. While both series of sulfamates and sulfonamides lowered serum cholesterol and triglyceride levels, the sulfamates were relatively more potent with regard to decreasing cholesterol levels, while the sulfonamides were more effective in lowering serum triglyceride levels in mice.
- Wyrick,Hall,Dubey
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p. 374 - 377
(2007/10/02)
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