835-64-3Relevant articles and documents
A two-photon ESIPT based fluorescence probe for specific detection of hypochlorite
Chen, Liyan,Park, Sang Jun,Wu, Di,Kim, Hwan Myung,Yoon, Juyoung
, p. 526 - 532 (2018)
Hypochlorous acid (HOCl) is one important member of reactive oxygen species (ROS) familyresponsible for various human diseases. Although many contributions have been made to develop fluorescent probes for sensing HOCl, many of them suffer small Stokes shifts, sophisticated synthetic procedure, and slow reaction rate. In the current study, we designed and synthesized an ESIPT based fluorescence probe with diaminomeleonitrile (DMN) as reactive site. The probe can detect HOCl with high selectivity and sensitivity. It also has large Stokes shift and rapid reaction rate. Moreover, it can be utilized to monitor exogenous and endogenous HOCl in living cells and tissues via two-photon microscopy.
Complexes of vanadyl and uranyl ions with a benzoxazole derivative: Synthesis, structural features and remarks on luminescence properties
Back, Davi Fernando,Manzoni de Oliveira, Gelson,Ballin, Marco Aurélio,Corbellini, Valeriano Antonio
, p. 807 - 812 (2010)
UO2(NO3)2·6H2O and VO(acac)2 react with 2-(2′-hydroxylphenyl)benzoxazole (Hpbx) in methanol to give [UO2(pbx)2(CH3OH)] (1) and [VO(pbx)2] (2). Complex 1 shows a distorted pentagonal bipyrimidal geometry, characteristic for the coordination number 7. Reciprocal OH?O interactions between neighbored molecules hold 1 in a pseudo-dimeric association with an inversion center. Complex 2 achieves a distorted octahedral geometry and the molecules "stack" along the b axis through secondary interactions. The molecule heaping is wholly linear, with Vn′-O(1)n′?V x′ angles of 180°. Luminescence properties of Hpbx, 1 and 2 are discussed.
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.
Development of homogeneous polyamine organocatalyst for the synthesis of 2-aryl-substituted benzimidazole and benzoxazole derivatives
Kottayil, Hiba,Machingal, Shaibuna,Parackal B., Sherly mole,Alungal M., Shebitha,Theresa, Letcy V.,Govindan, Avudaiappan,Krishnapillai, Sreekumar
, p. 3310 - 3317 (2020/07/17)
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.
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.
, (2019/11/11)
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.
Oxidative NHC catalysis for base-free synthesis of benzoxazinones and benzoazoles by thermal activated NHCs precursor ionic liquid catalyst using air as oxidant
Guan, Jiali,Liu, Wei,Liu, Yuchen,Song, Zhibin,Tao, Duan-Jian,Yan, Jieying,Yuan, Jian-Jun,Zhou, Youkang
, (2020/05/25)
A reusable thermal activated NHC precursor ionic liquid catalyst ([BMIm]2[WO4]) has been prepared and developed for the synthesis of nitrogen-containing heterocycles such as benzoxazinones and benzoazoles through imines activation. [BMIm]2[WO4] exhibited the good activity for the base-free condensation and oxidative NHC catalysis tandem under air atmosphere. The catalyst can be recovered and reused for at least five runs in gram scale synthesis without any decrease in catalytic activity. Furthermore, the control experiments demonstrated that the reaction involved formation of aromatic aldimines, NHC-catalyzed oxidative formation of imidoyl azoliums and intramolecular cyclization to generate the product.
Sulfur-Promoted Synthesis of Benzoxazoles from 2-Aminophenols and Aldehydes
Nguyen, Le Anh,Dang, Thai Duy,Ngo, Quoc Anh,Nguyen, Thanh Binh
supporting information, p. 3818 - 3821 (2020/06/10)
Elemental sulfur (S8) was found to be an excellent stoichiometric oxidant to promote oxidative condensation of 2-aminophenols with a wide range of aldehydes, including aliphatic aldehyde such as cyclohexanecarboxaldehyde. The reactions were catalyzed by sodium sulfide in the presence of DMSO as an additive. The benzoxazole products were obtained in satisfactory yields. The reaction conditions could be applied to larger syntheses (10–50 mmol).
Sulfur/DABCO Promoted Reductive Coupling/Annulation Cascade Reaction between o -Hydroxy/Amino Nitrobenzenes and Benzaldehydes
Dang, Minh-Huy Dinh,Nguyen, Linh Ho Thuy,Tran, Phuong Hoang
supporting information, p. 1687 - 1694 (2020/05/25)
Sulfur/DABCO was found to be an efficient reagent in promoting- the reductive coupling/annulation of o -nitrophenols or o -nitroanilines with benzaldehydes. This method represents a simple, straightforward, and green approach to the construction of benz-oxazoles and benzimidazoles.
Direct Oxygenation of C-H Bonds through Photoredox and Palladium Catalysis
Paul, Amrita,Shah, Sk. Sheriff,Shee, Maniklal,Singh, Amit Kumar,Singh, N. D. Pradeep
, p. 3426 - 3439 (2020/03/23)
This report presents the oxygenation of C-H bonds via the merger of photocatalysis and Pd catalysis. Herein, we describe the utilization of a photocatalyst to oxidize an organopalladium(II) intermediate to high-valent PdIII or PdIV intermediates, which promotes the formation of C-O bonds. The demonstrated method works efficiently with various directing groups, such as oxime ether and benzothiazole. The applicability of this direct C-O bond formation method is shown by synthesizing several metal complexes of 2-(benzo[d]thiazol-2-yl)phenol that can be used in organic light-emitting diodes and pharmaceuticals.
Synthesis of 2-(2-Hydroxyaryl)-4H-benzo[e][1,3]oxazin-4-ones by Palladium-Catalyzed C(sp2)?H Hydroxylation via Electro-chemical Oxidation
Wu, Hongfeng,An, Qi,He, Chaoyin,Fan, Xiaodong,Guo, Weihao,Zuo, Minghui,Xu, Chunzhao,Guo, Rui,Chu, Wenyi,Sun, Zhizhong
supporting information, p. 2459 - 2465 (2020/04/29)
An electrochemical direct ortho-hydroxylation of 2-aryl-4H-benzo[e][1,3]oxazin-4-ones was developed with Pd(OAc)2 as catalyst, oxazine ring as a directing group and Oxone as the hydroxylation reagent. A series of hydroxylation products were obtained under mild conditions, and the yields were from medium to good. This method is characterized by good functional group tolerance and a wide range of substrates. More importantly, use anodic oxidation to avoid the use of potentially toxic and polluting oxidants. A gram-scale direct electrochemical hydroxylation of 2-phenyl-4H-benzo[e][1,3]oxazin-4-one was performed, and the hydroxylation product was applied to synthesize the drug deferasirox. In addition, the single crystal of 2-(2-hydroxyphenyl)-4H-benzo[e][1,3]oxazin-4-one was obtained and determined by X-ray diffraction. Finally, the reaction mechanism was proposed and verified by cyclic voltammetry (CV). This protocol also provides an alternative electrochemical hydroxylation methodology for the functionalization of molecules. (Figure presented.).
