- Synthesis, Characterization and DFT-D Studies of 2-Aminoethoxycalix[4]resorcinarenes: A Novel Heterogeneous Organocatalyst
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The present article reports the synthesis of two novel supramolecular architectures, Phenyl(octa-2-aminoethoxy)calix[4]resorcinarene and 2-Aminoethoxyphenyl-(octa-2-aminoethoxy)calix[4]resorcinarene via surface functionalization and describes their applic
- Hiba, K.,Shaibuna, M.,Shebitha, A. M.,Sreekumar, K.
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- Phosphine-phosphonium ylides as ligands in palladium-catalysed C2-H arylation of benzoxazoles
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As balanced electron-rich P,C-chelating ligands, phosphine-phosphonium-ylides are considered for their ability to in situ promote palladium-catalysed direct C(sp2)–H arylation. Using methyl phosphonium salts of 2,2'-bis(diphenylphosphino)-1,1'-binaphtyl (“methyl-BINAPIUM”) as ylide precursors under optimized reaction conditions, arylation of benzoxazole was found to proceed in moderate to high yield to give functional 2-aryl benzoxazoles. A strong anion effect of the non-salt free ylide was evidenced (TfO? > I? > PF6? ≈ salt-free). This first example of phosphonium ylides as ligands in catalytic C–H activation extends the prospect of their general implementation in homogeneous transition metal catalysis.
- Yao, Zhenyu,Lin, Xing,Chauvin, Remi,Wang, Lianhui,Gras, Emmanuel,Cui, Xiuling
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p. 3250 - 3254
(2020/05/25)
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- Development of homogeneous polyamine organocatalyst for the synthesis of 2-aryl-substituted benzimidazole and benzoxazole derivatives
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A new polyamine was prepared by the ring opening polymerization of epichlorohydrin and properly characterized. The catalytic property of the prepared polymer was assessed by synthesizing 2-aryl-substituted benzimidazole and benzoxazole derivatives by the conjugation of o-phenylenediamine/o-aminophenol with various aromatic aldehydes in the presence of atmospheric oxygen. Significant attributes of the present synthesis include short reaction time, good to excellent yield, high purity, easy reusability, and room temperature reaction. The reaction was carried out in the absence of any metal catalyst and other cooxidants.
- Kottayil, Hiba,Machingal, Shaibuna,Parackal B., Sherly mole,Alungal M., Shebitha,Theresa, Letcy V.,Govindan, Avudaiappan,Krishnapillai, Sreekumar
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p. 3310 - 3317
(2020/07/17)
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- In-vitro Anti-cancer assay and apoptotic cell pathway of newly synthesized benzoxazole-N-heterocyclic hybrids as potent tyrosine kinase inhibitors
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A series of benzoxazole-N-heterocyclic hybrids have been synthesized by a one-pot strategy. Molecular docking study revealed that such compounds have the ability to inhibit enzyme protein tyrosine kinase. The findings of this work have been the successful synthesis of benzoxazole scaffolds, featuring hybrids of benzoxazole with quinoline and quinoxaline respectively. The molecular docking studies have showed these compounds to be inhibitors of tyrosine kinase enzyme which triggers growth of cancer cells. The cytotoxicity study of compounds 4a-f showed better potency against breast cancer cell lines MCF-7 and MDA-MB-231 in contrast to oral and lung cancer cell lines KB and A549. The tyrosine kinase activity was measured using Universal Tyrosine Kinase Assay kit using horseradish peroxide (HRP)-conjugated anti-phosphotyrosine kinase solution as a substrate. The compounds 4c exhibited maximum inhibition in the activity of enzyme tyrosine kinase with IC50 value 0.10 ± 0.16 μM, than other compounds which were studied and thus proved to be inhibitors of enzyme tyrosine kinase. The selective index of all four compounds was found out to be greater than two, indicating the non-toxic behaviour, i.e. good anti-cancer activity. Further, fluorescence microscopic study helped to characterize the mode of cell death, which was found to be late apoptosis as indicated by the orange fluorescence. The SAR analysis has also been carried out.
- Desai, Sulaksha,Desai, Vidya,Shingade, Sunil
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supporting information
(2019/11/13)
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- Pd/Cu bimetallic co-catalyzed direct 2-arylation of benzoxazole with aryl chloride
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An efficient Palladium/Copper bimetallic co-catalyzed direct 2-arylation of benzoxazoles with aryl chlorides is presented. The Pd(OAc)2/CuI/NiXantphos-based catalyst enables the installation of various aryl and heteroaryl groups in good to excellent yields (75–99%). Preliminary mechanism investigation indicates that Pd/Nixantphos complex activates C-Cl bond of aryl chlorides via oxidative addition, and Cu/Nixantphos complex chelates with nitrogen atom to lower the pKa of the 2-H in benzoxazoles.
- Zheng, Ling-Li,Yin, Bo,Tian, Xing-Chuan,Yuan, Ming-Yong,Li, Xiao-Huan,Gao, Feng
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supporting information
(2019/11/13)
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- Ni-Catalyzed C?F Bond Functionalization of Unactivated Aryl Fluorides and Corresponding Coupling with Oxazoles
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A Ni-catalyzed C?F bond functionalization of unactivated aryl fluorides with oxazoles as coupling partners was developed. Various arylated oxazoles could be obtained in moderate to good yields in the presence of Ni(cod)2/IMes catalytic system.
- Yin, Youzhi,Yue, Xiaoyu,Zhong, Qi,Jiang, Hanmin,Bai, Ruopeng,Lan, Yu,Zhang, Hua
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supporting information
p. 1639 - 1643
(2018/03/21)
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- Oxidative NHC Catalysis for the Generation of Imidoyl Azoliums: Synthesis of Benzoxazoles
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N-Heterocyclic carbene (NHC)-catalyzed intramolecular cyclization of aldimines generated from 2-amino phenols and aromatic aldehydes leading to the synthesis of 2-arylbenzoxazoles under mild conditions is presented. The reaction proceeds via the generation of the aza-Breslow intermediates from imines and NHC, which under oxidative conditions form the key imidoyl azoliums and a subsequent intramolecular cyclization furnishes the product. The reaction tolerates a broad range of functional groups, and the products are formed in generally good yields.
- Patra, Atanu,James, Anjima,Das, Tamal Kanti,Biju, Akkattu T.
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p. 14820 - 14826
(2019/01/03)
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- Transition-Metal-Free Cross-Coupling of Aryl and Heteroaryl Thiols with Arylzinc Reagents
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Cross-coupling of (hetero)arylthiols with arylzinc reagents via C-S cleavage was performed under transition-metal-free conditions. The reaction displays a wide scope of substrates and high functional-group tolerance. Electron-rich and -deficient (hetero)arylthiols and arylzinc reagents can be employed in this transformation. Mg2+ and Li+ ions were demonstrated to facilitate the reaction.
- Yang, Bo,Wang, Zhong-Xia
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supporting information
p. 6220 - 6223
(2017/11/24)
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- Optically operated second order optical effects in some substituted 4-(5-nitro-1,3-benzoxazol-2-yl)aniline chromophores
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In this work, we report on second order nonlinear optical (NLO) susceptibilities of some substituted 4-(5-nitro-1,3-benzoxazol-2-yl)aniline chromophores that were embedded into photopolymer matrices. Depending on the photo-induced nitrogen laser (waveleng
- Szlachcic,Fedorchuk,Danel,Jarosz,El Naggar,Albassam,Wojciechowski,Gondek,Uchacz,Stadnicka,Lakshminarayana,Kityk
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p. 333 - 341
(2017/03/08)
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- Magnetic Co-doped NiFe2O4 Nanocomposite: A Heterogeneous and Recyclable Catalyst for the One-Pot Synthesis of Benzimidazoles, Benzoxazoles and Benzothiazoles under Solvent-Free Conditions
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A simple and efficient procedure for the synthesis of benzimidazoles, benzoxazoles, and benzothiazoles via the condensation of o-phenylenediamine, o-aminophenol, and o-aminothiophenol with various benzaldehydes by using magnetic Co-doped NiFe2O4 nanoparticles has been developed. This nanocatalyst has advantages such as excellent product yields, solvent-free conditions, and very short reaction times. After any experiment, the magnetic nanocatalyst could be easily separated with the aid of an external magnet and reused at least four times without any loss of its catalytic performance.
- Karimian, Azam,Mohammadzadeh Kakhki, Roya,Kargar Beidokhti, Hamideh
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p. 1316 - 1325
(2017/11/22)
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- One-pot green synthesis of benzoxazole derivatives through molecular sieve-catalyzed oxidative cyclization reaction
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An one-pot approach to benzoxazole ring from 2-aminophenol and aldehydes utilizing molecular sieve as the catalyst have been developed. The new oxidative cyclization reaction excluded the usage of hazardous chemical reagents, transition-metal catalysts, chemical oxidants, or strong acids, and, therefore, reduced the production of toxic chemical waste. This offers an environmentally friendly pathway for the synthesis of various benzoxazole derivatives.
- Chang, Weichieh,Sun, Yukai,Huang, Yungtzung
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- Microwave Assisted Synthesis of Two-Substituted Benzoxazoles in the Presence of Potassium Cyanide under Mild Conditions
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Various two-substituted benzoxazoles were prepared using microwave-assisted reaction of 2-aminophenol with aromatic aldehydes in the presence of one equivalent of potassium cyanide as an equimolecular catalyst. Aldehydes having either electron-donating or withdrawing groups afforded the target products. The important features of this method were high yields, short reaction times and easy work up. The structure of synthesized products was characterized by nuclear magnetic resonance (NMR) and infrared (IR).
- Naeimi, Hossein,Rahmatinejad, Soraya
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p. 471 - 476
(2015/11/02)
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- Simple and efficient protocol for the synthesis of benzoxazole, benzoimidazole and benzothiazole heterocycles using Fe(III)–Schiff base/SBA-15 as a nanocatalyst
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Benzimidazoles, benzoxazoles, and benzothiazoles derivatives were synthesized from condensation of aldehydes and 1,2-phenylenediamine or ortho-aminophenol or ortho-aminothiophenol in the presence of catalytic amount of Fe(III)–Schiff base/SBA-15 in water
- Bardajee, Ghasem Rezanejade,Mohammadi, Marzieh,Yari, Hasan,Ghaedi, Aseyeh
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p. 265 - 270
(2018/03/22)
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- Copper(II)-diaminosarcophagine-functionalized SBA-15: A heterogeneous nanocatalyst for the synthesis of benzimidazole, benzoxazole and benzothiazole derivatives under solvent-free conditions
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Solvent-free organic reactions were studied over periodic mesoporous silica (SBA-15) containing a Cu(II) organometallic complex. This heterogeneous catalyst was achieved by coordination of Cu(II) ions with the diaminosarcophagine ligand and then its grafting onto the surface of SBA-15. This catalyst displayed ordered mesoporous channels, which implies an extremely high dispersion of the Cu(II) complex and the convenient diffusion of reactant molecules into the pore channels. Therefore, this catalyst can offer high activity and also facile separation or recycling when compared with its homogeneous counterparts.
- Bardajee, Ghasem Rezanejade,Mohammadi, Marzieh,Kakavand, Nahale
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- Palladium-Catalyzed C-H Arylation of (Benzo)oxazoles or (Benzo)thiazoles with Aryltrimethylammonium Triflates
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The C-H arylation of (benzo)oxazoles or (benzo)thiazoles with aryltrimethylammonium triflates was carried out via Pd-catalyzed C-H/C-N cleavage. Oxazoles, thiazoles, benzoxazole, and benzothiazole were arylated using activated and deactivated aryltrimethylammonium triflates to give 2-aryl(benzo)oxazoles or 2-aryl(benzo)thiazoles in reasonable to excellent yields.
- Zhu, Feng,Tao, Jian-Long,Wang, Zhong-Xia
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p. 4926 - 4929
(2015/10/12)
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- Magnetically separable nano CeO2: A highly efficient catalyst for ligand free direct C-H arylation of heterocycles
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An efficient, ligand free, nano CeO2-Fe3O4 catalyzed direct C-H arylation of heteroarenes such as benzoxazole and benzothiazole has been carried out with aryl halides in DMSO or arenediazonium salts in water. The catalyst exhibited high activity with moderate to excellent product yields under mild reaction conditions. Nano CeO2-Fe3O4 was synthesized and characterized by SEM, TEM, EDAX, XRD, FTIR, DSC-TGA, and ICP-MS analyses. The catalytic activity and stability of the catalyst were excellent, even after the ten cycle of recyclability
- Shelkar, Radheshyam S.,Balsane, Kishor E.,Nagarkar, Jayashree M.
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supporting information
p. 693 - 699
(2015/01/30)
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- Palladium-catalyzed synthesis of benzoxazoles by the cleavage reaction of carbon-carbon triple bonds with o-aminophenol
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A novel and mild procedure for efficient synthesis of benzoxazoles by the cleavage reaction of carbon-carbon triple bonds with o-aminophenol in the presence of a catalytic amount of palladium chloride has been successfully developed, which provides rapid and efficient access to benzoxazoles. the Partner Organisations 2014.
- Xie, Hou-Zhi,Gao, Qi,Liang, Ying,Wang, Heng-Shan,Pan, Ying-Ming
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supporting information
p. 2132 - 2135
(2014/04/17)
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- Room-temperature palladium-catalyzed direct 2-arylation of benzoxazoles with aryl and heteroaryl bromides
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An efficient room-temperature palladium-catalyzed direct 2-arylation of benzoxazoles with aryl bromides is presented. The Pd(OAc)2/ NiXantphos-based catalyst enables the introduction of various aryl and heteroaryl groups, via a deprotonative cross-coupling process (DCCP) in good to excellent yields (60-99%). This journal is the Partner Organisations 2014.
- Gao, Feng,Kim, Byeong-Seon,Walsh, Patrick J.
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supporting information
p. 10661 - 10664
(2014/10/15)
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- Nano ceria catalyzed synthesis of substituted benzimidazole, benzothiazole, and benzoxazole in aqueous media
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A series of substituted benzimidazoles, benzothiazoles, and benzoxazoles was synthesized by combining 1,2-phenylenediamine, 2-aminothiophenol, or 2-aminophenol with aryl, heteroaryl, aliphatic, α,β-unsaturated aldehydes in the presence of nano ceria (CeO2) as an efficient heterogeneous catalyst.
- Shelkar, Radheshyam,Sarode, Sachin,Nagarkar, Jayashree
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supporting information
p. 6986 - 6990
(2013/12/04)
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- Synthesis and in vitro antibacterial and antifungal activities of benzoxazole derivatives
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The in vitro antibacterial and antifungal activities of twenty-nine (29) benzoxazole derivatives were tested against fifteen Gram-positive and sixteen Gram-negative strains. Out of the twenty-nine compounds, eighteen compounds 3-5, 7-9, 11-13, 15-25 showed a broad range of activity against tested Gram-positive microorganisms, whereas rest of the compounds 6, 10, 14 and 26-31 were found to be completely inactive against all the tested strains of Gram-positive bacteria. Five compounds 8, 11-13, and 15 showed activities against Gram-negative strains whereas the rest were devoid of any activity. Twenty-one (21) out of twenty-nine (29) compounds possessed antifungal activity. The structures of the synthetic compounds were confirmed by IR, EIMS and 1HNMR spectral data.
- Khan, Khalid Mohammed,Karim, Aneela,Ambreen, Nida,Amyn, Afroz,Saied, Sumayya,Ahmed, Aqeel,Perveen, Shahnaz
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p. 894 - 900
(2013/07/26)
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- Sequential one-pot synthesis of benzoxazoles from aryl bromides: Successive palladium- and copper-catalyzed reactions
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A convenient one-pot process has been developed for the synthesis of benzoxazoles. Starting from aryl bromides and 1,2-dibromobenzenes palladium-catalyzed aminocarbonylation and subsequent copper-catalyzed coupling reaction gave a variety of substituted benzoxazoles in moderate to good yields.
- Wu, Xiao-Feng,Neumann, Helfried,Neumann, Stephan,Beller, Matthias
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supporting information
p. 3040 - 3042
(2013/06/27)
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- Pd(OAc)2 catalyzed synthesis of 2-aryl- and 2-heteroaryl- benzoxazoles and benzothiazoles in imidazolium ionic liquids (ILs) without additives and with recycling/reuse of the IL
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A facile, high yielding, method for the synthesis of a library of 2-aryl- and 2-heteroaryl-benzoxazoles and benzothiazoles from readily available Schiff bases is reported employing catalytic amounts of Pd(OAc)2 in imidazolium ionic liquids (bmim)BF4 and (bmim)PF6 without ligands and/or additives. Simple product isolation and recycling/re-use of the IL are additional advantages of this method.
- Kalkhambkar, Rajesh G.,Laali, Kenneth K.
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supporting information; experimental part
p. 4212 - 4215
(2012/08/28)
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- Carbonates: Eco-friendly solvents for palladium-catalysed direct arylation of heteroaromatics
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The palladium-catalysed direct 2-, 4- or 5-arylation of a wide range of heteroaromatics with aryl halides proceed in moderate to good yields using the eco-friendly solvents carbonates. The best yields were obtained using benzoxazole or thiazole derivatives. The arylation of furan, thiophene, pyrrole, imidazole or isoxazole derivatives was found to require a more elevated reaction temperature. The Royal Society of Chemistry 2010.
- Dong, Jia Jia,Roger, Julien,Verrier, Cecile,Martin, Thibaut,Le Goff, Ronan,Hoarau, Christophe,Doucet, Henri
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experimental part
p. 2053 - 2063
(2011/02/25)
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- Bienzymatic synthesis of benzothia/(oxa)zoles in aqueous medium
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A series of 2-arylbenzothiazoles and 2-arylbenzoxazoles were synthesized by the reactions of aldehydes and 2-aminothiophenol and 2-hydroxythiophenol, respectively, using glucose oxidase (GOX)-chloroperoxidase (CPO) catalytic system under oxygen atmosphere.
- Kumar, Atul,Sharma, Siddharth,Maurya, Ram Awatar
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experimental part
p. 6224 - 6226
(2011/01/04)
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- An efficient procedure for the synthesis of benzoxazole and benzothiazole derivatives using a H2O2/SiO2-FeCl3 system
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A series of benzoxazole and benzothiazoles was readily prepared from the reaction of ortho-aminophenol/ortho-aminothiophenol and aldehydes using solid silica supported ferric chloride (SiO2-FeCl3) as catalyst followed by oxidation with H2O2 under ambient conditions. Some of advantages of this method are a simple and convenient procedure, easy purification, and shorter reaction times. Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file. Copyright Taylor & Francis Group, LLC.
- Mosslemin, Mohammad Hossein,Fazlinia, Abbas
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experimental part
p. 2165 - 2170
(2011/01/12)
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- Efficient one-step synthesis of benzazoles in aqueous media
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Benzazoles (benzoxazoles, benzothiazoles, and benzimidazoles) were efficiently prepared by the aquatic reaction of the corresponding thioamidinium salts and 2-aminophenol, 2-aminothiophenol, and 1,2-diaminobenzene, respectively. The thioamidinium salt was successfully applied as an alternative to a carboxylic acid derivative to react smoothly with an amino precursor and in the presence of catalytic amounts of hexadecyltrimethylammonium bromide salt to produce benzazoles in good to excellent yields. Wiley-VCH Verlag GmbH & Co. KGaA 2009.
- Boeini, Hassan Zali,Najafabadi, Khadijeh Hajibabaei
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supporting information; experimental part
p. 4926 - 4929
(2010/01/18)
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- Direct arylation of oxazole and benzoxazole with aryl or heteroaryl halides using a palladium-diphosphine catalyst
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Through the use of PdCl(dppb)(C3H5) as a catalyst, a range of aryl bromides and chlorides undergoes coupling via C-H bond activation/functionalization reaction with oxazole or benzoxazole in good yields. This air-stable catalyst can be used at low loadings with several substrates. Surprisingly, better results in terms of substrate/catalyst ratio were obtained in several cases using electron-excessive aryl bromides than with the electron-deficient ones. This seems to be mainly due to the relatively low thermal stability of some of the 2-arylbenzoxazoles formed with electron-deficient aryl halides. With these substrates, in order to obtain higher yields of product, the reactions had to be performed at a lower temperature (100-120 °C) using a larger amount of catalyst. On the other hand, in the presence of the most stable products, the reactions were performed at 150 °C using as little as 0.2 mol% catalyst. Arylation of benzoxazole with heteroaryl bromides also gave the coupling products in moderate to high yields using 0.2-5 mol% catalyst. With this catalyst, electron-deficient aryl chloride such as 4-chlorobenzonitrile, 4-chloroacetophenone or 2-chloronitrobenzene have also been used successfully.
- Derridj, Fazia,Djebbar, Safia,Benali-Baitich, Ouassini,Doucet, Henri
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p. 135 - 144
(2008/03/30)
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- A simple and efficient one step synthesis of benzoxazoles and benzimidazoles from carboxylic acids
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Benzoxazoles or benzimidazoles can be rapidly and efficiently synthesized from a variety of carboxylic acids with 2-aminophenols or 1,2-phenylenediamines in one simple step, respectively. The use of commercially available PS-PPh3 resin combined with microwave heating delivered a variety of benzoxazoles and benzimidazoles in high yields and purities.
- Wang, Ying,Sarris, Kathy,Sauer, Daryl R.,Djuric, Stevan W.
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p. 4823 - 4826
(2007/10/03)
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- One-step synthesis of 2-arylbenzothiazole ('BTA') and -benzoxazole precursors for in vivo imaging of β-amyloid plaques
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We report the simple and efficient synthesis of 2-arylbenzothiazoles ('BTA') and 2-arylbenzoxazoles by direct coupling of benzothiazoles or benzoxazoles with aryl bromides. This method permits direct one-step access to precursors of radiolabeled BTA-1 and
- Alagille, David,Baldwin, Ronald M.,Tamagnan, Gilles D.
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p. 1349 - 1351
(2007/10/03)
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- BARIUM MANGANATE OXIDATION IN ORGANIC SYNTHESIS: PART III: OXIDATION OF SCHIFF'S BASES TO BENZIMIDAZOLES, BENZOXAZOLES AND BENZTHIAZOLES
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The oxidative cyclisation of benzylideneamino anilines, phenols and thiophenols to benzimidazoles, benzoxazoles and benzthiazoles respectively using barium manganate is described.
- Srivastava, R. G.,Venkataramani, P. S.
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p. 1537 - 1544
(2007/10/02)
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- SYNTHESIS OF HETEROCYCLES: PART I. N-IODOSUCCINIMIDE, A CONVENIENT OXITATIVE CYCLISING AGENT IN THE SYNTHESIS OF OXAZOLE, ISOXAZOLE, BENZOFURAN, FUROXAN AND 1,2,3-TRIAZOLE-1-OXIDE DERIVATIVES
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N-Iodosuccinimide has been successfully employed as an oxidative cyclising agent for the synthesis of oxazole, isoxazole, benzofuran, furoxan and 1,2,3-triazole-1-oxide derivatives.Synthesis of compounds (II), (IV), (VI), (VIII) and (X) having these basic skeletons respectively are reported.
- Talapatra, Sunil K.,Chaudhuri, Prabir,Talapatra, Bani
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p. 1279 - 1282
(2007/10/02)
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