- Solid-phase rhodium carbenoid reactions: an N-H insertion route to a diverse series of oxazoles.
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[reaction: see text] The solid-phase synthesis of a series of oxazoles is described. The key step in the construction of these molecules involves the rhodium-catalyzed decomposition of polymer-bound alpha-diazo-beta-ketoesters. These reactions are performed in the presence of primary amides and yield the corresponding N-H insertion products. Subsequent cyclodehydration of these alpha-(acylamino)-beta-ketoesters provides the corresponding resin-bound 2,5-disubstituted oxazoles, which are further elaborated during cleavage from the resin.
- Clapham,Spanka,Janda
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Read Online
- RhII-catalyzed cycloadditions of carbomethoxy iodonium ylides
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Carbomethoxy iodonium ylides, generated from methyl acetoacetate and methyl malonate, respectively, are exploited in synthesis of cyclopropanes, cyclopropenes as well as various heterocycles.
- Batsila, Christina,Kostakis, George,Hadjiarapoglou, Lazaros P
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Read Online
- Electrochemical synthesis of 1,2,4,5-tetrasubstituted imidazoles from enamines and benzylamines
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An electrochemical method for synthesizing 1,2,4,5-tetrasubstituted imidazoles was developed under undivided electrolytic conditions. This synthesis was specifically realized based on electrochemical C(sp3)-H aminationviaenamines and amines. Readily available starting materials were used, avoiding the use of both transition metals and oxidants. The practicability of the method lies in its broad substrate adaptability and in its ability to provide a simple green pathway for synthesizing GABAAreceptor analogs.
- Chen, Zhiwei,Shi, Guang,Wang, Wenxing,Zhang, Shuo
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supporting information
p. 6682 - 6686
(2021/08/12)
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- A Highly Efficient Heterogeneous Copper-Catalyzed Oxidative Cyclization of Benzylamines and 1,3-Dicarbonyl Compounds to Give Trisubstituted Oxazoles
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The heterogeneous copper-catalyzed cascade oxidative cyclization between benzylamines and 1,3-dicarbonyl compounds was achieved by using the 3-(2-aminoethylamino)propyl-functionalized MCM-41-immobilized copper(II) complex [MCM-41-2N-Cu(OAc) 2 ] as catalyst and t -BuOOH (TBHP) as oxidant, with iodine as additive, under mild conditions, yielding a wide variety of 2,4,5-trisubstituted oxazoles in mostly good to excellent yields. This heterogeneous copper catalyst can be facilely prepared via a simple two-step procedure from readily available and inexpensive reagents and exhibits a slightly higher activity than Cu(OAc) 2. MCM-41-2N-Cu(OAc) 2 is also easy to recover and can be recycled up to eight times with almost consistent activity. The reaction is the first example of heterogeneous copper-catalyzed intermolecular cyclization for the construction of polysubstituted oxazoles.
- Cai, Mingzhong,Tuo, Yuxin,Wei, Li,You, Shengyong
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p. 3091 - 3100
(2019/08/07)
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- The rapid synthesis of oxazolines and their heterogeneous oxidation to oxazoles under flow conditions
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A rapid flow synthesis of oxazolines and their oxidation to the corresponding oxazoles is reported. The oxazolines are prepared at room temperature in a stereospecific manner, with inversion of stereochemistry, from β-hydroxy amides using Deoxo-Fluor. The
- Gl?ckner, Steffen,Tran, Duc N.,Ingham, Richard J.,Fenner, Sabine,Wilson, Zoe E.,Battilocchio, Claudio,Ley, Steven V.
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p. 207 - 214
(2015/02/02)
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- Convenient route to trisubstituted oxazoles via a copper-catalysed tandem oxidative cyclisation by oxygen oxidation
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A novel copper-catalysed oxidative cyclisation has been developed for the synthesis of trisubstituted oxazoles, which is thought to proceed through cascade formation of C-N and C-O bonds by oxygen oxidation. The desired products can be obtained from readily available starting materials while avoiding hazardous materials. Therefore, a green synthetic method for the preparation of oxazoles has been found.
- Chen, Chengqun,Chen, Wenfu,Bao, Qianhong
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- Electrochemically promoted synthesis of polysubstituted oxazoles from β-diketone derivatives and benzylamines under mild conditions
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An efficient electrochemical synthesis of poly-substituted oxazoles from readily available β-diketone derivatives and benzylamines is described. This electrochemical procedure does not need hazardous oxidants and transition metal catalysts as well as molecular I2 additives. Compared with the traditional thermo-chemical method, the present electrochemical method is greener and more efficient. The Royal Society of Chemistry 2014.
- Yuan, Gaoqing,Zhu, Zechen,Gao, Xiaofang,Jiang, Huanfeng
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p. 24300 - 24303
(2014/06/24)
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- Synthesis of new β-amidodehydroaminobutyric acid derivatives and of new tyrosine derivatives using copper catalyzed C-N and C-O coupling reactions
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Several β-amidodehydroaminobutyric acid derivatives were prepared from N,C-diprotected β-bromodehydroaminobutyric acids and amides by a copper catalyzed C-N coupling reaction. The best reaction conditions include the use of a catalytic amount of CuI, N,N'-dimethylethylenediamine as ligand and K 2CO3 as base in toluene at 110 C. The stereochemistry of the products was determined using NOE difference experiments and the results obtained are in agreement with an E-stereochemistry. Thus, the stereochemistry is maintained in the case of the E-isomers of β-bromodehydroaminobutyric acid derivatives, but when the Z-isomers were used as substrates the reaction proceeds with inversion of configuration. The use of β- bromodehydrodipeptides as substrates was also tested. It was found that the reaction outcome depend on the stereochemistry of the β- bromodehydrodipeptide and on the nature of the first amino acid residue. The products isolated were the β-amidodehydrodipeptide derivatives and/or the corresponding dihydropyrazines. The same catalytic system (CuI/N,N'- dimethylethylene diamine) was used in the C-O coupling reactions between a tyrosine derivative and aryl bromides. The new O-aryltyrosine derivatives were isolated in moderate to good yields. The photophysical properties of two of these compounds were studied in four solvents of different polarity. The results show that these compounds after deprotection can be used as fluorescence markers.
- Pereira,Vilaca,Ferreira
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p. 335 - 344
(2013/07/05)
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- Metal-free, organocatalytic cascade formation of C-N and C-O bonds through dual sp3 C-H activation: Oxidative synthesis of oxazole derivatives
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An organocatalytic cascade reaction that involves the formation of C-N, C-O and CN bonds in one process via dual sp3 C-H activation has been developed. This protocol affords a facile metal-free methodology for the synthesis of oxazole derivatives in air under mild conditions.
- Xie, Jin,Jiang, Honglai,Cheng, Yixiang,Zhu, Chengjian
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supporting information; experimental part
p. 979 - 981
(2012/02/04)
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- A mild high yielding synthesis of oxazole-4-carboxylate derivatives
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Several 2,5-disubstituted oxazole-4-carboxylates were prepared in high yields from the methyl esters of N-acyl-β-halodehydroaminobutyric acid derivatives by treatment with a 2% solution of DBU in acetonitrile. The scope of this reaction was investigated a
- Ferreira, Paula M.T.,Castanheira, Elisabete M.S.,Monteiro, Luís S.,Pereira, Goreti,Vilaa, Helena
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experimental part
p. 8672 - 8680
(2011/01/04)
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- Facile synthesis of polysubstituted oxazoles via A copper-catalyzed tandem oxidative cyclization
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A highly efficient synthesis of polysubstituted oxazoles was developed via a copper-catalyzed tandem oxidative cyclization. The desired products can be obtained from readily available starting materials under mild conditions. This is an attractive alterna
- Wan, Changfeng,Zhang, Jintang,Wang, Sujing,Fan, Jinmin,Wang, Zhiyong
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supporting information; experimental part
p. 2338 - 2341
(2010/08/04)
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- Rhodium carbene routes to oxazoles and thiazoles. Catalyst effects in the synthesis of oxazole and thiazole carboxylates, phosphonates, and sulfones
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(Chemical Equation Presented) Dirhodium tetraacetate catalyzed reaction of α-diazo-β-keto-carboxylates and -phosphonates with arenecarboxamides gives 2-aryloxazole-4-carboxylates and 4-phosphonates by carbene N-H insertion and cyclodehydration. In stark contrast, dirhodium tetrakis(heptafluorobutyramide) catalysis results in a dramatic change of regioselectivity to give oxazole-5-carboxylates and 5-phosphonates. α-Diazo-β-ketosulfones behave similarly and give 5-sulfonyloxazoles upon dirhodium tetrakis-(heptafluorobutyramide) catalyzed reaction with carboxamides. The analogous reactions of thiocarboxamides give the corresponding thiazole-5-carboxylates, -phosphonates, and -sulfones. 2009 American Chemical Society.
- Shi, Baolu,Blake, Alexander J.,Lewis, William,Campbell, Ian B.,Judkins, Brian D.,Moody, Christopher J.
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experimental part
p. 152 - 161
(2010/04/04)
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- The rhodium carbene route to oxazoles: A remarkable catalyst effect
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Dirhodium tetraacetate catalysed reaction of α-diazo-β-keto- carboxylates and -phosphonates with arenecarboxamides gives 2-aryloxazole-4- carboxylates and 4-phosphonates by carbene N-H insertion and cyclodehydration; in stark contrast, dirhodium tetrakis(
- Shi, Baolu,Blake, Alexander J.,Campbell, Ian B.,Judkins, Brian D.,Moody, Christopher J.
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body text
p. 3291 - 3293
(2009/12/01)
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- Towards Gram-negative antivirulence drugs: New inhibitors of HldE kinase
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Gram-negative bacteria lacking heptoses in their lipopolysaccharide (LPS) display attenuated virulence and increased sensitivity to human serum and to some antibiotics. Thus inhibition of bacterial heptose synthesis represents an attractive target for the development of new antibacterial agents. HldE is a bifunctional enzyme involved in the synthesis of bacterial heptoses. Development of a biochemical assay suitable for high-throughput screening allowed the discovery of inhibitors 1 and 2 of HldE kinase. Study of the structure-activity relationship of this series of inhibitors led to highly potent compounds.
- Desroy, Nicolas,Moreau, Francois,Briet, Sophia,Fralliec, Geraldine Le,Floquet, Stephanie,Durant, Lionel,Vongsouthi, Vanida,Gerusz, Vincent,Denis, Alexis,Escaich, Sonia
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experimental part
p. 1276 - 1289
(2009/07/11)
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- Synthesis of substituted oxazoles from N-acyl-β-hydroxyamino acid derivatives
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Several N-acyl-β-hydroxyamino acids were prepared and treated with di-tert-butyl dicarbonate in the presence of 4-(dimethylamino)pyridine, followed by treatment with N,N,N′,N′-tetramethylguanidine to give the corresponding N-acyldehydroamino acids in good
- Ferreira, Paula M. T.,Monteiro, Luis S.,Pereira, Goreti
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experimental part
p. 4676 - 4683
(2009/05/27)
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- NOVEL COMPOUNDS AS AGONIST FOR PPAR GAMMA AND PPAR ALPHA, METHOD FOR PREPARATION OF THE SAME, AND PHARMACEUTICAL COMPOSITION CONTAINING THE SAME
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The present invention relates to novel compounds accelerating the activity of Peroxisome proliferator-activated receptor gamma (PPARγ) and alpha (PPARα), processes of preparing the same, and pharmaceutical compositions containing the same as an active agent.
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Page/Page column 155
(2010/02/11)
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- Oxidative dehydrogenation of dihydropyrimidinones and dihydropyrimidines
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(Chemical Equation Presented) A mild, practical procedure for oxidative dehydrogenation with catalytic amounts of a Cu salt, K2CO 3, and tert-butylhydroperoxide (TBHP) as a terminal oxidant has been developed. This oxidation procedure is generally applicable to dihydropyrimidinones and most dihydropyrimidines.
- Yamamoto, Kana,Chen, Ye Grace,Buono, Frederic G.
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p. 4673 - 4676
(2007/10/03)
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- Carboxylic acid derivatives and drugs containing the same as the active ingredient
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A peroxisome proliferator activated receptor regulator containing a compound of formula (I) (wherein all symbols are as defined in the specification), or a salt thereof as active ingredient. Because of having an effect of regulating PPAR, a compound of fo
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- Combinatorial synthesis and biological evaluation of library of small-molecule Ser/Thr-protein phosphatase inhibitors
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In eukaryotes, phosphorylation of serine, threonine, and tyrosine residues on proteins is a fundamental posttranslational regulatory process for such functions as signal transduction, gene transcription, RNA splicing, cellular adhesion, apoptosis, and cell cycle control. Based on functional groups present in natural product serine/threonine protein phosphatase (PSTPase) inhibitors, we have designed pharmacophore model 1 and demonstrated the feasibility of a combinatorial chemistry approach for the preparation of functional analogues of 1. Preliminary biological testing of 18 structural variants of 1 has identified two compounds with growth inhibitory activity against cultured human breast cancer cells. In vitro inhibition of the PSTPase PP2A was demonstrated with compound Id. Using flow cytometry we observed that compound If caused prominent inhibition in the G1 phase of the cell cycle. Thus, the combinatorial modifications of the minimal pharmacophore 1 can generate biologically interesting antiproliferative agents.
- Wipf, Peter,Cunningham, April,Rice, Robert L.,Lazo, John S.
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p. 165 - 177
(2007/10/03)
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