1141-35-1Relevant articles and documents
Efficient one-pot synthesis of benzoxazole derivatives catalyzed by nickel supported silica
Maddila, Suresh,Jonnalagadda, Sreekanth B.
, p. 1099 - 1100,2 (2012)
A simple and efficient method has been developed for the synthesis of benzoxazoles from 2-aminophenol and substituted aldehydes in the presence of a catalytic amount of nickel supported silica at room temperature.
Phosphine-phosphonium ylides as ligands in palladium-catalysed C2-H arylation of benzoxazoles
Yao, Zhenyu,Lin, Xing,Chauvin, Remi,Wang, Lianhui,Gras, Emmanuel,Cui, Xiuling
, p. 3250 - 3254 (2020)
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.
Heterogeneous palladium (II)-complexed dendronized polymer: A rare palladium catalyst for the one-pot synthesis of 2-arylbenzoxazoles
George, Smitha,Sreekumar, Krishnapillai
, (2021)
The palladium complex of dendronized amine polymer (EG–Gn–Pd, n = 0, 1 and 2) having ethylene glycol-initiated polyepichlorohydrin as core was synthesized on a Merrifield resin support and was well characterized. Generally, palladium catalysts are known for carbon–carbon coupling reactions. Here, a developed catalyst was found to be good for benzoxazole synthesis. Higher generation dendronized polymer (EG–G2–Pd) was found to be better catalyst over lower generation dendronized polymers. Moreover, dendronized polymers were found to be a better catalyst over dendrigraft polymers. The catalyst reusability was checked and good yield was obtained for five cycles.
Catalyst-free microwave-promoted one pot synthesis of 2-aryl benzoxazoles using MnO2 nanoparticles as a convenient oxidant under mild condition
Naeimi, Hossein,Rouzegar, Zahra,Rahmatinejad, Soraya
, p. 4745 - 4758 (2017)
Abstract: An efficient and facile protocol for one pot synthesis of a series of 2-aryl benzoxazoles through coupling of o-aminophenol with aromatic aldehydes under microwave irradiation in the presence of MnO2 nanoparticles as oxidant reagent was demonstrated. The MnO2 nanoparticles were prepared via a solid-state chemical reaction technique. The structure of oxidant was assigned by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The target molecules were obtained in good to high yields, high purity and short reaction times. The pure products were identified and characterized by physical and spectral data such as; melting point, IR, 1H NMR and 13C NMR. Graphical Abstract: An efficient and facil protocol for one pot synthesis of a series of 2-aryl benzoxazoles through coupling of o-aminophenol with aromatic aldehydes under microwave irradiation in the precense of MnO2 nanoparticles as oxidant reagent was demonstrated.
Efficient protocol for the synthesis of quinoxaline, benzoxazole and benzimidazole derivatives using glycerol as green solvent
Bachhav, Harshal M.,Bhagat, Saket B.,Telvekar, Vikas N.
, p. 5697 - 5701 (2011)
A straightforward, efficient and more sustainable catalyst-free method has been developed for the synthesis of quinoxaline, benzoxazole, and benzimidazole ring system in glycerol to achieve yields that were comparable to or better than, those in conventional media. It is noteworthy that the reaction was exclusively carried out in glycerol-water system, rendering the methodology highly valuable from both environment and economic points of view.
A Facile Synthesis of 2-Substituted Benzoxazoles
Terashima, Masanao,Ishii, Masako
, p. 484 - 485 (1982)
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Bywater et al.
, p. 905 (1945)
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Intramolecular O-arylation route to 2-substituted benzoxazoles mediated by ferrocene tethered polymer supported ionic liquid phase catalyst
Jadhav, Jagannath,Gaikwad, Vipul,Kurane, Rajanikant,Salunkhe, Rajashri,Rashinkar, Gajanan
, p. 2920 - 2926 (2013)
A novel ferrocene tethered polymer supported ionic liquid phase catalyst has been synthesized and successfully applied for intramolecular O-arylation of o-iodoanilides to corresponding benzoxazoles. The catalyst was easily recovered by simple filtration that greatly simplified the purification step and resulted in quantitative yields, without ionic liquid impurities in the products.
Microwave Assisted Synthesis of Two-Substituted Benzoxazoles in the Presence of Potassium Cyanide under Mild Conditions
Naeimi, Hossein,Rahmatinejad, Soraya
, p. 471 - 476 (2016)
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).
Synthesis and X-ray crystal structures of three new nickel(II) complexes of benzoylhydrazones: Catalytic applications in the synthesis of 2-arylbenzoxazoles
Layek, Samaresh,Agrahari, Bhumika,Kumar, Akash,Dege, Necmi,Pathak, Devendra D.
, (2020)
Three new complexes of nickel(II), having general formula [Ni(L1)(PPh3)] (1), [Ni(L1)(4-picoline)] (2), and [Ni(L2)(4-picoline)] (3) were synthesized by the reaction of Ni(OAc)2·4H2O with corresponding benzolyhydrazine-derived Schiff base ligands i.e. [4-(diethylamino)-2-hydroxybenzylidene]-benzohydrazonic acid (H2L1) or [2-(hydroxynaphthalen-1-yl)methylene]-benzohydrazonic acid (H2L2) and PPh3/4-picoline as co-ligand in 1:1:1 ratio in methanol. All the three complexes were air-stable, isolated as reddish brown solids and characterized by Elemental analysis, FT-IR, 1H, 13C{1H}, 31P{1H} NMR spectroscopy and mass spectrometry. The structures of all three complexes were determined by single crystal X-ray diffraction studies which revealed the distorted square planar geometry of the complexes. In these complexes, three coordination sites were occupied by ONO pincer type Schiff base ligand and the fourth site was blocked by phosphorus (P) or nitrogen (N) atom of the co-ligand. The catalytic potential of all three complexes was explored in the synthesis of a series of 2-arylbenzoxazoles from aldehydes and 2-aminophenol, using low catalyst loading (0.5 mol%). Complex 1 was found to be the best catalyst among three complexes, for the synthesis of a series of 2-aryl benzoxazoles. The ease of synthesis, air-stability and robustness of the catalyst, and good TONs are some of the key characteristics of the described catalytic system.
Iodine-mediated synthesis of 2-arylbenzoxazoles, 2-arylbenzimidazoles, and 1,3,5-trisubstituted pyrazoles
Ponnala, Shashikanth,Prasad Sahu, Devi
, p. 2189 - 2194 (2006)
2-Arylbenzoxazoles and 2-arylbenzimidazoles were synthesized by the reaction of aldehydes with 2-aminophenol and O-phenylenediamines in the presence of iodine. 1,3,5-Trisubstituted pyrazoles were synthesized from chalcones and hydrazines in the presence o
Sonocatalyzed facile synthesis of 2-aryl benzoxazoles using MnO2 nanoparticles as oxidant agent under mild conditions
Naeimi, Hossein,Rouzegar, Zahra,Rahmatinejad, Soraya
, p. 2087 - 2095 (2017)
Nano MnO2 was found to be an efficient oxidant agent for the synthesis of 2-substituted benzoxazoles through one-pot reaction of o-aminophenol and different aromatic aldehydes in acetonitrile under ultrasonic irradiation. This method was performed under mild conditions with high yields, inexpensive and readily available oxidant agent, facile and easy experimental procedure, simple purification of final products, and short reaction times. The prepared nano MnO2 has been characterized by FTIR, XRD, and SEM techniques. The pure products were identified and characterized by physical and spectroscopic data such as; melting point, IR, 1H NMR, and 13C NMR.
Mixed N-heterocycles/N-heterocyclic carbene palladium(II) allyl complexes as precatalysts for direct arylation of azoles with aryl bromides
Yang, Jin
, p. 2182 - 2187 (2019)
A series of mixed N-heterocycles/N-heterocyclic carbene palladium(II) allyl complexes with general formula [(NHC)Pd(η3-allyl)]2(μ2-N-heterocycles)(BF4)2 were prepared in one pot based on anion metathesis of (NHC)Pd(η3-allyl)Cl complexes and then ligand replacement with N-heterocycles [N-heterocycles = pyrazine (pyz), 4,4′-bipyridine (bpy) and trans-4,4′-bipyridylethylene (bpe)]. The solid-state structures shown dinuclear structures with two palladium(II) centers holding together by bridged N-heterocycles. Initially investigation of the obtained complexes as precatalysts for direct C[sbnd]H bond arylation of azoles with aryl bromides was carried out.
Zn(OAc)2 · 2H2O-catalyzed, simple, and clean procedure for the synthesis of 2-substituted benzoxazoles using a grindstone method
Madhusudana Reddy,Nizam, Aatika,Pasha
, p. 1838 - 1842 (2011)
Zn(OAc)2 · 2H2O efficiently catalyzes the condensation reaction between 2-aminophenol and various araldehydes to afford the 2-substituted benzoxazoles in good to excellent yields. The remarkable features of this protocol are simple and mild reaction conditions, use of readily available catalyst, and shorter reaction time, and in addition the reaction proceeds just by grinding the substrates and catalyst without any solvent and hence matches the green chemistry protocols.
Synthesis of benzimidazoles and benzoxazoles using TiCl3OTf in ethanol at room temperature
Azizian, Javad,Torabi, Parviz,Noei, Jalil
, p. 185 - 188 (2016)
An efficient and practical procedure for the synthesis of benzimidazoles and benzoxazoles in high yields by the coupling of o-phenylenediamines or o-aminophenol with aldehydes using TiCl3OTf in ethanol at ambient temperature is described.
Copper-catalyzed oxidative arylation of heteroarenes under mild conditions using dioxygen as the sole oxidant
Yang, Fanzhi,Xu, Zhaoqing,Wang, Zhe,Yu, Zhengkun,Wang, Rui
, p. 6321 - 6325 (2011)
Dioxy-gently does it! A new copper-catalyzed oxidative cross-coupling reaction between heteroarenes and arylboronic esters has been developed. Uniformly high yields are obtained by using dioxygen as the sole oxidant under mild conditions (see scheme). Copyright
Facile and efficient one-pot protocol for the synthesis of benzoxazole and benzothiazole derivatives using molecular iodine as catalyst
Moghaddam, Firouz Matloubi,Bardajee, Ghasem Rezanejade,Ismaili, Hossein,Taimoory, Seyedeh Maryam Dokht
, p. 2543 - 2548 (2006)
Rapid and efficient condensation reactions of 2-aminothiophenol and 2-aminophenol with various aldehydes were carried out using I2 in solvent-free conditions with or without microwave irradiation to afford the corresponding 2-substituted benzothiazole and benzoxazole derivatives in good to excellent yields. Copyright Taylor & Francis Group, LLC.
Sustainable Synthesis of 2-Arylbenzoxazoles over a cobalt-based nanocomposite catalyst
He, Jian,Lin, Fu,Yang, Xufang,Wang, Di,Tan, Xiaohua,Zhang, Shujun
, p. 1093 - 1096 (2016)
A new cobalt-based heterogeneous catalyst was prepared by adsorbing in situ produced nitrogen-ligated cobalt(II) acetate complexes on commercially available SiO2 and subsequent pyrolysis at 800 °C for 2 h under N2 atmosphere. By applying this catalyst under the O2 balloon, the aerobic oxidation of phenolic imines proceeded smoothly and gave various 2-arylbenzoxazoles in good yields. Meanwhile, on the basis of the experimental results, a plausible reaction pathway was described to elucidate the reaction mechanism.
Fluorinated phosphoric acid as a versatile effective catalyst for synthesis of series of benzimidazoles, benzoxazoles and benzothiazoles at room temperature
Mathapati, Sushil R.,Patil, Komal N.,Mathakari, Sujit S.,Suryawanshi, Appasaheb W.,Jadhav, Arvind H.
, p. 538 - 547 (2021)
The present work describes synthesis of a series of benzimidazoles, benzoxazoles and benzothiazoles through the cyclization of 1, 2-phenylenediamine, 2-aminothiophenol, or 2-aminophenol with aryl, aliphatic and heteroaryl aldehydes. The present synthetic protocol is very much efficient in presence of 5 mol % fluorophosphoric acid as a catalyst in ethanol solvent at room temperature. Shorter reaction time, simple work-up technique, high yields and easy availability are specific compensations of the present synthetic approach.
Hypervalent iodine oxidation of phenolic Schiff's bases: Synthesis of 2-arylbenzoxazoles
Varma, Rajender S.,Saini, Rajesh K.,Prakash, Om
, p. 2621 - 2622 (1997)
2-Arylbenzoxazole, 6, are synthesized, rapidly and in high yields, via the oxidative intramolecular cyclization of phenolic Schiff's bases, 4, using iodobenzene diacetate (IBD) as an oxidant in acetonitrile or methanol at room temperature.
Ag@TiO2 nanocomposite; Synthesis, characterization and its application as a novel and recyclable catalyst for the one-pot synthesis of benzoxazole derivatives in aqueous media
Maleki, Behrooz,Baghayeri, Mehdi,Vahdat, Seyed Mohammad,Mohammadzadeh, Abbas,Akhoondi, Somaieh
, p. 46545 - 46551 (2015)
In the present study, we use a Ag@TiO2 nanocomposite for the efficient synthesis of benzoxazole derivatives via the one-pot condensation of 2-aminophenol and several aromatic aldehydes or orthoesters or carboxylic acids or amides or acyl chlorides in water at room temperature. In all situations the preferred products were synthesized with excellent yields. The short reaction times, high yields, safety and mild conditions, simplicity, non-toxicity and easy workup are the main merits of this protocol.
Samarium(III) triflate: A new catalyst for facile synthesis of benzothiazoles and benzoxazoles from carboxylic acids in aqueous media
Gorepatil, Pratapsinha B.,Mane, Yogesh D.,Gorepatil, Amarsinha B.,Gaikwad, Mahadev V.,Ingle, Vilas S.
, p. 8355 - 8362 (2015)
A facile synthetic method for benzothiazoles and benzoxazoles comprising the reaction of corresponding 2-aminothiophenol and 2-aminophenol with various substituted aromatic carboxylic acids using Samarium(III) triflate as a catalyst has been described. The advantages of the method are short reaction times and aqueous reaction media and easy work-up. The catalysts can be recovered for the subsequent reactions and reused without any appreciable loss of efficiency.
Synthesis, Characterization and DFT-D Studies of 2-Aminoethoxycalix[4]resorcinarenes: A Novel Heterogeneous Organocatalyst
Hiba, K.,Shaibuna, M.,Shebitha, A. M.,Sreekumar, K.
, (2022/01/12)
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
Pd/Cu-Catalyzed C-H/C-H Cross Coupling of (Hetero)Arenes with Azoles through Arylsulfonium Intermediates
Lin, Zeng-Hui,Tian, Ze-Yu,Zhang, Cheng-Pan
, p. 4400 - 4405 (2021/06/27)
A highly efficient method for the selective formal C-H/C-H cross-coupling of azoles and (hetero)arenes was established through arylsulfonium intermediates under transition-metal catalysis, which produced a variety of 2-(hetero)aryl azoles in good to excellent yields. Advantages of the reaction included mildness, a good functional group tolerance, a wide range of substrates, a high regio- and chemoselectivity, one-pot procedures, and the late-stage functionalization of complex molecules without the use of oxidants, offering a promising strategy for the transition-metal-catalyzed C-H arylation of azoles.
