1141-35-1Relevant academic research and scientific papers
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.
Study on photochromic diarylethene with phenolic schiff base: Preparation and photochromism of diarylethene with benzoxazole
Chen, Yi,Zeng, De X.
, p. 5037 - 5040 (2004)
A photochromic diarylethene with phenolic Schiff base 1a can be easily transformed to photochromic diarylethene with benzoxazole 3a in the conditions of base and phototrigger. Both of their photochromic properties are investigated. They show that the conversions of ring-open form to ring-closed form at photostationary equilibrium are ca. 20% and 10% for 3a and 1a, respectively, and the backconversions are in nearly quantitative yield for both compounds. They also show that the response time for photostationary equilibrium is ca. 0.5 and 5 min for 3a and 1a, respectively, in the solution. In addition, a general preparation of 2-arylbenzoxazole from phenolic Schiff base in the conditions of base and phototrigger is demonstrated by employing phenolic Schiff bases with different substituted groups as template, and other conditions (solvents, in the presence and absence of oxygen) for preparation of benzoxazole from phenolic Schiff base are explored as well.
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.
Towards applications of metal-organic frameworks in catalysis: C-H direct activation of benzoxazole with aryl boronic acids using Ni2(BDC) 2(DABCO) as an efficient heterogeneous catalyst
Phan, Nam T. S.,Nguyen, Chung K.,Nguyen, Tung T.,Truong, Thanh
, p. 369 - 377 (2014)
A crystalline porous metal-organic framework Ni2(BDC) 2(DABCO) was synthesized and characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), Fourier transform infrared (FT-IR), atomic absorption spectrophotometry (AAS), and nitrogen physisorption measurements. The Ni2(BDC)2(DABCO) could be used as an efficient heterogeneous catalyst for the nickel-catalyzed direct heterocycle C-H arylation reactions between azoles and arylboronic acids forming 2-arylbenzoxazoles as the principal product. This approach avoids the use of hazardous aryl halides as well as the formation of halide byproducts in the synthesis of aryl-substituted benzoxazoles. The Ni2(BDC) 2(DABCO) exhibited significantly higher catalytic activity than that of other Ni-MOFs such as Ni3(BTC)2, Ni(HBTC)(BPY), and that of some common nickel salts such as NiCl2, Ni(NO 3)2, Ni2SO4, and Ni(OAc) 2. To the best of our knowledge, application of Ni 2(BDC)2(DABCO) in the field of catalysis as well as the C-C cross coupling reaction via direct C-H functionalization using a nickel heterogeneous catalyst have not previously been reported in the literature. The Royal Society of Chemistry.
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.
Oxidative conversion of amines into benzoxazoles using hydrogen transfer catalysis
Blacker, A. John,Farah, Mohamed M.,Marsden, Stephen P.,Saidi, Ourida,Williams, Jonathan M.J.
, p. 6106 - 6109 (2009)
Benzoxazoles are synthesised directly by oxidative condensation of primary and secondary amines with o-aminophenols under hydrogen transfer catalysis. The optimal system utilises 1 mol % of the Shvo catalyst, with dimethoxybenzoquinone as the hydrogen-acc
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.
KMnO4/HOAc system promoted one-pot synthesis of benzoxazoles from o-aminophenols or oxidative cyclization of o-hydroxyarylidene anilines at room temperature
Mirjalili,Bamoniri,Bagheri
, p. 809 - 814 (2016)
1,3-Benzoxazoles via oxidative cyclization of corresponding o-hydroxyarylidene anilines was synthesized in the presence of KMnO4/HOAc system. This system also was applied for the one-pot synthesis of 1,3-benzoxazoles from o-amino phenols and aldehydes. The both protocols were processed at room temperature under solvent-free conditions with good to excellent yields.
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.
One-pot synthesis of 2-arylbenzoxazoles promoted by heteropolyacids
Heravi, Majid M.,Sadjadi, Samaheh,Oskooie, Hossein A.,Shoar, Rahim Hekmat,Bamoharram, Fatemeh F.
, p. 890 - 895 (2008)
Benzoxazole derivatives were obtained in high yields with excellent purity from the condensation of 2-aminophenol with benzaldehydes and benzoic acids in the presence of a catalytic amount of heteropolyacids (HPAs).
