838-34-6Relevant articles and documents
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
An efficient rapid synthesis of benzoxazoles and benzothiazoles using pma.Sio2 at room temperature under heterogeneous conditions
Sudhakar, Chithaluri,Shekhar, Vanam,Shyamsunder, Manchi,Suryakumari, Adurthi,Manojkumar, Vala
, p. 583 - 587 (2021/09/30)
Treatment of 2-aminophenol (or 2-aminothiophenol) with aromatic aldehydes in the presence of phosphomolybdic acid on silica at room temperature affords the corresponding benzoxazoles (or benzothiazoles) in excellent yields (88-96%) under heterogeneous conditions. Benzoxazoles and benzothiazoles are formed in less than 10 min.
Syntheses, characterization, and catalytic potential of novel vanadium and molybdenum Schiff base complexes for the preparation of benzimidazoles, benzoxazoles, and benzothiazoles under thermal and ultrasonic conditions
Kargar, Hadi,Kargar, Khadijeh,Fallah-Mehrjardi, Mehdi,Munawar, Khurram Shahzad
, p. 593 - 605 (2021/06/21)
A new ONO-tridentate Schiff base ligand (H2L) derived from 3-methoxysalicylaldehyde and nicotinic hydrazide was synthesized and characterized by elemental analysis, FT-IR, 1H NMR, 13C NMR, UV–Vis, and powder XRD studies. Then, oxovanadium(V) and dioxomolybdenum(VI) Schiff base complexes, VOL and MoO2L, were also prepared and characterized by different techniques. Moreover, the catalytic activities of both complexes were investigated for the synthesis of benzimidazoles, benzoxazoles, and benzothiazoles under reflux conditions as well as through ultrasonic irradiation. The results revealed several advantages of this procedure, including high product yields, short reaction times, facile work-up procedure, simplicity in operation, eco-friendly reaction conditions, and green aspects by avoiding toxic catalysts and solvents. Graphic abstract: [Figure not available: see fulltext.]
A TEMPO-Functionalized Ordered Mesoporous Polymer as a Highly Active and Reusable Organocatalyst
Guo, Ying,Wang, Wei David,Li, Shengyu,Zhu, Yin,Wang, Xiaoyu,Liu, Xiao,Zhang, Yuan
supporting information, p. 3689 - 3694 (2021/09/29)
The properties of high stability, periodic porosity, and tunable nature of ordered mesoporous polymers make these materials ideal catalytic nanoreactors. However, their application in organocatalysis has been rarely explored. We report herein for the first time the incorporation of a versatile organocatalyst, 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO), into the pores of an FDU-type mesoporous polymer via a pore surface engineering strategy. The resulting FDU-15-TEMPO possesses a highly ordered mesoporous organic framework and enhanced stability, and shows excellent catalytic activity in the selective oxidation of alcohols and aerobic oxidative synthesis of 2-substituted benzoxazoles, benzimidazoles and benzothiazoles. Moreover, the catalyst can be easily recovered and reused for up to 7 consecutive cycles.
Dowex 50W: A green mild reusable catalyst for the synthesis of 2-aryl benzoxazole derivatives in aqueous medium
Datta, Arup
, p. 341 - 347 (2021/05/19)
In this work simple efficient, one pot and environmentally friendly method was developed for the synthesis of 2-Aryl-1H-benzoxazole derivatives at 80oC using ortho-aminophenol and various aldehydes. It has been found that Dowex 50W is an effective catalyst to prepare moderate to high yield of a variety of benzoxazole derivatives through a clean and simple process. Aqueous medium, green methodology, rapid reaction, reusability of heterogeneous catalyst are the great advantages of this protocol.
Heterogeneous palladium (II)-complexed dendronized polymer: A rare palladium catalyst for the one-pot synthesis of 2-arylbenzoxazoles
George, Smitha,Sreekumar, Krishnapillai
, (2020/12/14)
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.
Novel and efficient heterogeneous polymer supported copper catalyst for synthesis of 2-substituted Benzoxazoles from 2-Haloanilides
Saranya, Thachora Venu,Sruthi, Pambingal Rajan,Raj, Veena,Anas, Saithalavi
supporting information, (2021/02/27)
A novel polymer supported copper complex is prepared by the immobilization of copper iodide on chemically modified polyacrylonitrile and its application in heterogeneous catalysis is described. The catalyst was prepared by easy method via synthetic modification of Polyacrylonitrile (PAN) using ethylene diamine followed by the complexation with CuI. After characterization, this complex was explored as a green and efficient heterogeneous catalyst for the synthesis of 2-benzoxazoles from 2-haloanilides. The reaction was performed without adding additional ligand and the catalyst shows activity over a broad range of substrates with quantitative product yields. The catalyst was easily recovered by simple filtration and reused successfully for further cycle.
Delivering 2-Aryl Benzoxazoles through Metal-Free and Redox-Neutral De-CF3Process
Qiao, Xinxin,Zhao, Yong-De,Rao, Mingru,Bu, Zhan-Wei,Zhang, Guangwu,Xiong, Heng-Ying
, p. 13548 - 13558 (2021/10/01)
An unexpected cleavage of the Csp3-CF3 bond of CF3-hydrobenzoxazoles has been disclosed, affording a range of 2-aryl benzoxazoles under metal-free and redox-neutral conditions. This transformation has demonstrated broad substrate scope and good compatibility of functional groups. 2-Aryl benzothiazole and 2-aryl benzoimidazole could be smoothly assembled in the same manner. On the basis of preliminary mechanistic studies, base initiated and aromatization driven β-carbon elimination was considered to be the key step for the formation of 2. This reaction offers an alternative, facile, and sustainable route to access important 2-aryl benzoxazole motifs.
TEMPO-mediated aerobic oxidative synthesis of 2-aryl benzoxazoles via ring-opening of benzoxazoles with benzylamines
Rao, Mugada Sugunakara,Hussain, Sahid
, p. 2684 - 2694 (2021/07/26)
A simple and efficient TEMPO-mediated system for aerobic oxidative synthesis of 2-aryl benzoxazoles from readily available benzoxazoles and primary benzylic and hetero benzylic amines is presented in one pot. The reaction proceeds through the ring-opening of benzoxazoles and is followed by oxidative condensation with benzylamines. These metal-free, straightforward reactions worked well with a wide range of substrates, yielding moderate to good yields under mild conditions using air as an external green oxidant.
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.
