- Expanding the Balz–Schiemann Reaction: Organotrifluoroborates Serve as Competent Sources of Fluoride Ion for Fluoro-Dediazoniation
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The Balz–Schiemann reaction endures as a method for the preparation of (hetero)aryl fluorides yet is eschewed due to the need for harsh conditions or high temperatures along with the need to isolate potentially explosive diazonium salts. In a departure from these conditions, we show that various organotrifluoroborates (RBF3?s) may serve as fluoride ion sources for solution-phase fluoro-dediazoniation in organic solvents under mild conditions. This methodology was successfully extended to a one-pot process obviating aryl diazonium salt isolation. Sterically hindered (hetero)anilines are fluorinated under unprecedentedly mild conditions in good-to-excellent yields. Taken together, this work expands the repertoire of RBF3?s to act as fluorine ion sources in an update to the classic Balz–Schiemann reaction.
- Mohy El Dine, Tharwat,Sadek, Omar,Gras, Emmanuel,Perrin, David M.
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supporting information
p. 14933 - 14937
(2018/09/25)
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- Compounds for modulating TRPV3 function
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The present application relates to compounds and methods for treating pain and other conditions related to TRPV3.
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Page/Page column 155
(2016/11/24)
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- Synthesis of aryl ethers from benzoates through carboxylate-directed C-H-activating alkoxylation with concomitant protodecarboxylation
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One in, one out: In the presence of a copper/silver bimetallic catalyst system, aromatic carboxylate salts undergo ortho C-H alkoxylation with concomitant loss of the carboxylate directing group in a protodecarboxylation step (see scheme, FG=functional group). This process provides a convenient synthetic access to the important class of aromatic ethers from widely available carboxylic acids. Copyright
- Bhadra, Sukalyan,Dzik, Wojciech I.,Goo?en, Lukas J.
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p. 2959 - 2962
(2013/04/10)
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- Synthesis of aryl ethers from aromatic carboxylic acids
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A silver/copper bimetallic catalyst system promotes the decarboxylative Chan-Evans-Lam alkoxylation of ortho-substituted aromatic carboxylate salts with tetraalkyl orthosilicates or triaryl borates. Non-ortho-substituted carboxylates are alkoxylated via an ortho-C-H-alkoxylation with concomitant cleavage of the carboxylate directing group via protodecarboxylation. This way, meta-substituted carboxylates are converted into para-substituted alkoxyarenes and vice versa. The combined processes provide a convenient synthetic entry to the important class of aromatic ethers from widely available carboxylic acids.
- Bhadra, Sukalyan,Dzik, Wojciech I.,Goossen, Lukas J.
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supporting information
p. 2387 - 2390
(2013/09/23)
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- Aromatic nitration with bismuth nitrate in ionic liquids and in molecular solvents: A comparative study of Bi(NO3)3·5H 2O/[bmim][PF6] and Bi(NO3)3· 5H2O/1,2-DCE systems
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A suspension of bismuth nitrate pentahydrate (BN) in [bmim][PF6] or [bmim][BF4] imidazolium ionic liquid (IL) is an effective reagent for ring nitration of activated aromatics under mild conditions without the need for external promoters. Nitration can also be effected in 1,2-DCE, MeCN, or MeNO2 without additives. Nitration of activated arenes (anisole, toluene, ethylbenzene, cumene, p-xylene, mesitylene, durene, and 1,3-dimethoxybenzene) is considerably faster (time to completion) in BN/[bmim][PF6] relative to BN/1,2-DCE and there are also differences in isomer distributions (for anisole, toluene, and ethylbenzene). With introduction of strongly deactivating substituents (-CHO; -MeCO; -NO 2) the BN/IL system is no longer active but reactions still proceed with BN/1,2-DCE in reasonable yields. The ready availability and low cost of BN, simple operation, and absence of promoters, coupled to recycling and reuse of the IL, provide an attractive alternative to classical nitration methods for activated arenes. Switching from Bi(NO3)3·5H 2O/[bmim][PF6] to Bi(NO3)3· 5H2O/1,2-DCE increases the scope of the substrates that can be nitrated.
- Jacoway, Jonathan,Kumar, G. G. K. S. Narayana,Laali, Kenneth K.
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p. 6782 - 6785,4
(2012/12/12)
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- Copper catalyzed ipso-nitration of iodoarenes, bromoarenes and heterocyclic haloarenes under ligand-free conditions
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A catalytic protocol for the conversion of haloarenes into the corresponding nitroarenes is presented using copper salts under ligand-free conditions. The method was effectively utilized for the ipso-nitration of a broad variety of haloarenes that includes iodoarenes, bromoarenes, and heterocyclic haloarenes.
- Amal Joseph,Priyadarshini,Lakshmi Kantam,Maheswaran
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supporting information; experimental part
p. 1511 - 1513
(2012/03/27)
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- A molecular balance for measuring aliphatic CH-π interactions
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A series of conformationally flexible bicyclic N-arylimides were employed as molecular balances to study the weak aliphatic CH-π interaction between alkyl and arene groups. The formation of intramolecular CH-π interactions in the folded conformers was characterized by X-ray crystallography. The strengths of the interactions were characterized in CDCl3 by the changes in the folded/unfolded ratios, as measured by 1H NMR. The CH-π interaction between a methyl group and an aromatic surface was ~1.0 kcal/mol and was easily disrupted or masked by conformational entropy and repulsive steric interactions.
- Carroll, William R.,Zhao, Chen,Smith, Mark D.,Pellechia, Perry J.,Shimizu, Ken D.
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supporting information; experimental part
p. 4320 - 4323
(2011/10/05)
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- Synthesis and biological evaluation of phenstatin metabolites
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Previous investigations on the incubation of phenstatin with rat and human microsomal fractions revealed the formation of nine main metabolites. The structures of eight of these metabolites have been now confirmed by synthesis and their biological properties have been reported. Eaton's reagent was utilized as a convenient condensing agent, allowing, among others, a simple multigram scale preparation of phenstatin. Synthesized metabolites and related compounds were evaluated for their antiproliferative activity in the NCI-60 cancer cell line panel, and for their effect on microtubule assembly. Metabolite 23 (2′-methoxyphenstatin) exhibited the most potent in vitro cytotoxic activity: inhibition of the growth of K-562, NCI-H322M, NCI-H522, KM12, M14, MDA-MB-435, NCI/ADR-RES, and HS 578T cell lines with GI50 values 50 = 3.2 μM vs 15.0 μM) and induced G2/M arrest in murine leukemia DA1-3b cells. The identification of this active metabolite led to the design and synthesis of analogs with potent in vitro cytotoxicity and inhibition of microtubule assembly.
- Ghinet, Alina,Rigo, Beno?t,Hénichart, Jean-Pierre,Le Broc-Ryckewaert, Delphine,Pommery, Jean,Pommery, Nicole,Thuru, Xavier,Quesnel, Bruno,Gautret, Philippe
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supporting information; experimental part
p. 6042 - 6054
(2011/11/29)
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- A synthesis of sulfonamide analogs of platensimycin employing a palladium-mediated carbonylation strategy
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The monodentate ligand 1,3,5,7-tetramethyl-2,4,8-trioxa-6-phenyl-6-phospha-adamantane (PA-Ph) is shown to be highly effective in palladium-catalyzed carbonylative cross-coupling. Aryl and vinyl halides were efficiently converted to carboxylic acids, amides and to primary, secondary, and tertiary esters, respectively. Application of the Pd(OAc)2/PA-Ph (1:1) catalyst system proved critical in the methoxycarbonylation of a functionalized nitroresorcinol halide, allowing convenient access to novel platensimycin sulfonamide analogs.
- McNulty, James,Nair, Jerald J.,Capretta, Alfredo
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scheme or table
p. 4087 - 4091
(2009/12/01)
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- Compounds for modulating TRPV3 function
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The present application relates to compounds and methods for treating pain and other conditions related to TRPV3.
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Page/Page column 56
(2010/11/28)
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- Electrophilic tetraalkylammonium nitrate nitration. II. Improved anhydrous aromatic and heteroaromatic mononitration with tetramethylammonium nitrate and triflic anhydride, including selected microwave examples
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A new one-pot nitration employing tetramethylammonium nitrate and trifluoromethanesulfonic anhydride in dichloromethane to provide a ready source of the nitronium triflate nitrating agent is presented. Rapid and selective nitration with a variety of aromatic and heteroaromatic substrates is achieved resulting in the synthesis of several novel organic compounds. A distinct advantage is the removal of undesired byproducts by aqueous workup. This very mild nitration permits large-scale syntheses and gives high isolated product yields that often require no further purification. This tetramethylammonium nitrate-based nitration also has been applied to microwave-assisted conditions, and the results with several compounds are outlined.
- Shackelford, Scott A.,Anderson, Mark B.,Christie, Lance C.,Goetzen, Thomas,Guzman, Mark C.,Hananel, Martha A.,Kornreich, Wayne D.,Li, Haitao,Pathak, Ved P.,Rabinovich, Alex K.,Rajapakse, Ranjan J.,Truesdale, Larry K.,Tsank, Stella M.,Vazir, Haresh N.
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p. 267 - 275
(2007/10/03)
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- Synthesis of novel orthoalkylaminophenol derivatives as potent neuroprotective agents in vitro.
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A series of orthoalkylaminophenol derivatives was synthesized and tested in vitro with respect to their neuroprotective effect. Some of these compounds exhibited a potent antioxidant activity close to that of standard α-tocopherol.
- Larget, Ronan,Lockhart, Brian,Pfeiffer, Bruno,Neudorffer, Anne,Fleury, Maurice-Bernard,Largeron, Martine
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p. 2929 - 2934
(2007/10/03)
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- Nitration of electron-rich aromatic compounds by cerium ammonium nitrate coated on silica
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Treatment of electron-rich aromatic derivatives with cerium (IV) ammonium nitrate coated on silica (CANSio2) affords nitro aromatic compounds. The scope and the limitation of this reaction are discussed.
- Grenier, Jean-Luc,Catteau, Jean-Pierre,Cotelle, Philippe
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p. 1201 - 1208
(2007/10/03)
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