- A lipophilic thioflavin-T derivative for positron emission tomography (PET) imaging of amyloid in brain
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The synthesis of a new lipophilic thioflavin-T analogue (2-[4′-(methylamino)phenyl]benzothiazole, 6) with high affinity for amyloid is reported. Intravenous injection of [11C]-labeled 6 in control mice resulted in high brain uptake. Amyloid dep
- Mathis, Chester A.,Bacskai, Brian J.,Kajdasz, Stephen T.,McLellan, Megan E.,Frosch, Matthew P.,Hyman, Bradley T.,Holt, Daniel P.,Wang, Yanming,Huang, Guo-Feng,Debnath, Manik L.,Klunk, William E.
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- Facile one-pot synthesis of 4-aryl-3-methyl-1-phenylpyrazolo[3,4-b]-[1,5] benzothiazepine derivatives via a regioselective nucleophilic addition
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4-Arylidene-3-methyl-1-phenylpyrazole-5-one reacts with 2-aminobenzenethiol in ethanol-acetic acid solution to produce a mixture of 4-aryl-3-methyl-1-phenylpyrazolo[3,4-b][1,5]benzothiazepines, 2-arylbenzothiazoles and 3-methyl-1-phenylpyrazole-5-one.
- Abd El Latif, Fawi M.,El Rady, Eman A.
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- Iodine-catalyzed, one-pot, solid-phase synthesis of benzothiazole derivatives
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Molecular iodine was utilized in a one-pot, solid-phase, solvent-free reaction between 2-aminothiophenol and benzoic acid derivatives to obtain highly economical and excellent yield of benzothiazole derivatives in comparison to polyphosphoric acid- and [pmIm]-Br-catalyzed microwave synthesis reactions. The results of the studies revealed that the new method reduces cost by approximately 17-fold in comparison to polyphosphoric acid and has a significant cost reduction in comparison to [pmIm]-Br. Moreover, it becomes even more economical because no additional chemicals and solvents are necessary for the reaction. Copyright Taylor & Francis Group, LLC.
- Gupta, Sayan Dutta,Singh, Hemendra Pratap,Moorthy
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- An efficient conversion of phenolic esters to benzothiazoles under mild and virtually neutral conditions
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Phenolic esters are efficiently converted to 2-substituted benzothiazoles in a one-pot reaction by treatment with 2-aminothiophenol in the presence of a catalytic amount of K2CO3 in N-methyl-2-pyrrolidone (NMP) at 100°C.
- Chakraborti, Asit K.,Rudrawar, Santosh,Kaur, Gurmeet,Sharma, Lalima
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- Method for catalyzing nitrogen heterocyclic ring aerobic dehydrogenation based on ionic liquid porous carbon material
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The invention discloses a method for catalyzing nitrogen heterocycle aerobic dehydrogenation based on an ionic liquid porous carbon material, and is suitable for the field of organic synthesis. A heterogeneous catalysis system takes nitrogen heterocycle and derivatives thereof as substrates, a carbon material as a catalyst, water or ethanol as a solvent and air or oxygen spheres as an oxygen source, and a reaction is carried out at 0-80 DEG C under normal pressure, oxidative dehydrogenation of nitrogen heterocyclic compounds can be realized, and target products such as indole, quinoline, isoquinoline, quinazoline, quinoxaline, benzothiazole, Hanus ester and derivatives thereof and other medical intermediates can be synthesized. The non-metal catalyst is prepared by using the ionic liquid as the precursor, no activating agent or other additives are used in the reaction process, and the method has industrial application prospects.
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Paragraph 0040-0043
(2022/01/24)
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- A biomass-derived N-doped porous carbon catalyst for the aerobic dehydrogenation of nitrogen heterocycles
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N-doped porous carbon (NC) was synthesized from sugar cane bagasse, which is a sustainable and widely available biomass waste. The preferred NC sample had a well-developed porous structure, a graphene-like surface morphology and different N species. More
- Cui, Fu-Jun,Guo, Fu-Hu,Liu, Jing-Jiang,Liu, Xiao-Yu,Quan, Zheng-Jun,Ullah, Arif,Wang, Xi-Cun,Zhu, Ji-Hua
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supporting information
p. 1791 - 1799
(2022/01/31)
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- Method for catalytically synthesizing benzothiazole compound by using copper complex
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The invention relates to a method for catalytically synthesizing benzothiazole compounds by using a copper complex, which is characterized in that a copper complex containing ortho-carborane Schiff base ligand is used as a catalyst to form aldehydes. 2 - Bromoaniline and sodium sulfide are used as raw materials, and the reaction is carried out at room temperature to obtain a benzothiazole compound. Compared with the prior art, the copper complex catalytic aldehyde, 2 -bromoaniline and sodium sulfide (Na) containing the ortho-carborane Schiff base ligand are utilized. 2 Multiple components of S) react to prepare benzothiazole compounds, and the catalyst is low in dosage, mild in reaction conditions, high in reaction rate, high in yield, wide in substrate range, cheap and accessible in raw materials and wide in application prospect in industry.
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Paragraph 0056-0067
(2021/09/22)
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- Heterocyclic reaction inducted by Br?nsted–Lewis dual acidic Hf-MOF under microwave irradiation
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Use of green chemistry and alternative strategies has been explored to prepare diverse organic derivatives. The combination between heterogeneous catalyst, environmentally benign reaction and high-yielding methods is gaining momentum. Herein, a defective 6-connected Hf-MOF, named Hf-BTC, was efficiently synthesized and characterized for the heterogeneous catalysis under microwave irradiation. The MOF features including structural defect, porosity, acidity, and stability was analyzed by powder X-ray diffraction, N2 sorption isotherms, acid-base titration, and thermal gravimetric analysis. In the catalytic studies, the Br?nsted-Lewis dual acidic Hf-BTC was efficiently applied for the synthesis of the heterocyclic compounds via the microwave-assisted cycloaddition and condensation reactions. The reactions proceeded smoothly in the presence of the Hf-MOF with a broad scope of substrates provided the expected products in high to excellent yields (up to 99 %) for few minutes and the catalyst could be easily recycle over many consecutive reactions without loss of its reactivity and structure.
- Nguyen, Linh Ho Thuy,Nguyen, Trang Thi Thu,Dang, Minh-Huy Dinh,Tran, Phuong Hoang,Doan, Tan Le Hoang
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- Novel series of benzo[d]thiazolyl substituted-2-quinolone hybrids: Design, synthesis, biological evaluation and in-silico insights
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A novel series of 3-(2-(4-(substituted-benzo[d]thiazol-2-yl)phenylamino)acetyl)-4?hydroxy-1-methyl/phenyl quinolin-2(1H)-one (7a-f and 8a-f) were synthesized. Reaction of appropriately substituted-2-(4-amino phenyl)benzo[d]thiazole (4a-f) with 3-(2-bromoacetyl)-4?hydroxy-1-methyl/phenyl quinolin-2(1H)-one (5/6) in the presence of glacial acetic acid resulted in desired compounds. Structures of the synthesized compounds were characterized based on their spectral (IR, 1H NMR, 13C NMR and MS) and elemental analysis. The cytotoxicity screening studies revealed that MCF-7 and WRL68 cancer cells were sensitive to all the tested compounds. Out of twelve novel hybrids, compound 8f displayed the most significant anticancer activity. Docking studies were performed in order to understand the binding mode of the title compounds at the active site of the target enzyme (EGFR tyrosine kinase, 1M17). Compounds 8f and 7f displayed prominent and conserved binding interactions against 1M17. In addition, compounds 7e, 7f, 8e, and 8f exhibited interesting in vitro antibacterial activity, especially against Gram-negative bacteria E. coli. In summary, the novel benzo[d]thiazolyl substituted-2-quinolone hybrid (8f) could be considered as promising hit and could be further exploited for developing potential anticancer/antimicrobial agents.
- Bolakatti, Girish,Palkar, Mahesh,Katagi, Manjunatha,Hampannavar, Girish,Karpoormath, Rajshekhar V.,Ninganagouda, Shilpa,Badiger, Arvind
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- Fast and high-efficiency synthesis of 2-substituted benzothiazoles via combining enzyme catalysis and photoredox catalysis in one-pot
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An efficient and green method, combining enzymatic and visible-light catalysis for synthesis of the widely applicable 2-substituted benzothiazoles, has been developed. This method features a relay catalysis protocol consisting of biocatalytic promiscuity
- Yang, Zeng-Jie,Gong, Qing-Tian,Yu, Yuan,Lu, Wei-Fan,Wu, Zhe-Ning,Wang, Na,Yu, Xiao-Qi
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supporting information
(2021/01/14)
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- Ultrasound-assisted efficient and green synthesis of 2-substituted benzothiazoles under solvent-free condition using recyclable sulfated tungstate
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Sulfated tungstate catalyzed an efficient and ecofriendly protocol has been described for the synthesis of 2-substituted benzothiazoles. The corresponding benzothiazoles were obtained using a condensation reaction of 2-aminothiophenol with various aldehydes under ultrasound irradiation at room temperature. Various functional groups on the 2-aminothiophenol as well as on the aldehydes were tolerated to provide 2-substituted benzothiazoles derivatives in excellent yields. The faster reaction rate, solvent-free or mild reaction conditions, wide functional group compatibility, excellent yields, easy work-up procedure, and excellent catalyst recyclability are the advantages of this protocol. These advantages make this process more practicable, cost-effective, and environmentally benign.
- Pise, Ashok S.,Ingale, Ajit P.,Dalvi, Navnath R.
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supporting information
p. 3629 - 3641
(2021/10/12)
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- Camphor sulfonic acid catalyzed a simple, facile, and general method for the synthesis of 2-arylbenzothiazoles, 2-arylbenzimidazoles, and 3H-spiro[benzo[d]thiazole-2,3′-indolin]-2′-ones at room temperature
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A simple, mild, eco-friendly, general, and convenient approach has been developed for the synthesis of structurally diverse 2-arylbenzothiazole derivatives from the reactions of 2-aminothiophenol and various aromatic aldehydes using camphor sulfonic acid
- Kaur, Gurpreet,Moudgil, Radha,Shamim, Mussarat,Gupta, Vivek Kumar,Banerjee, Bubun
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supporting information
p. 1100 - 1120
(2021/01/20)
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- Ruthenium silicate (RS-1) zeolite: novel heterogeneous efficient catalyst for synthesis of 2-arylbenzothiazole derivatives
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Abstract: Mesoporous silicate and transition metal (Ru+3) containing mesoporous silicate materials or ruthenium silicate Ru+3/Si+4 where synthesis by using hydrothermal process. Mesoporous ruthenium silicate (RS-1) and zeo
- Gadekar, Sachin P.,Lande, Machhindra K.
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p. 1253 - 1267
(2021/01/06)
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- Ionic liquid-immobilized hybrid nanomaterial: an efficient catalyst in the synthesis of benzimidazoles and benzothiazoles via anomeric-based oxidation
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Abstract: In this study, a novel ionic liquid immobilized on silica-coated cobalt-ferrite magnetic nanoparticles. This novel hybrid nanostructure (CoFe2O4@SiO2@PAF-IL) was characterized by various microscopic and spectroscopic techniques including Fourier transformation infrared spectroscopy (FT–IR), X-ray powder diffraction (XRD), field emission scanning electron microscopy (SEM), the electron-dispersive X-ray spectroscopy (EDS), vibrating sample magnetometer (VSM), and thermogravimetric analysis (TGA/DTG). The catalytic activity of prepared nanomaterial was considered in the synthesis of the benzothiazole and benzimidazole derivatives. This method has several advantages such as good to excellent yields, short reaction times, solvent-free and environmentally-benign conditions, and simple work-up. Besides, nanocatalyst can be easily separated from the reaction mixture with the external magnetic field and reused several times without any loss of its catalytic activity. Graphic abstract: [Figure not available: see fulltext.].
- Bodaghifard, Mohammad Ali,Shafi, Saeideh
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p. 677 - 687
(2020/09/18)
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- Pentafluorophenylammonium Triflate: A Mild, Efficient and Reusable Catalyst for the Synthesis of 2-Arylbenzothiazole and 2-Arylbenzothiazoline Derivatives in a Green Chemical Approach
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In this work, one pot, simple and environmentally benign effective synthesis of 2-substituted benzothiazole and benzothiazoline derivatives are described in presence of PFPAT (pentafluorophenylammonium triflate) catalyst in water successfully. A series of benzothiazole derivative were synthesized by the reaction between 2-aminothiophenol and various aldehydes in good yields. Recyclability of the catalyst is observed for four times without loss of its activity in aqueous medium.
- Datta, Arup
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- 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
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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.]
- Kargar, Hadi,Kargar, Khadijeh,Fallah-Mehrjardi, Mehdi,Munawar, Khurram Shahzad
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p. 593 - 605
(2021/06/21)
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- Ruthenium(II)-catalyzed synthesis of 2-arylbenzimidazole and 2-arylbenzothiazole in water
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Benzimidazoles/benzothiazoles are heterocyclic compounds which contain a five membered heteroatom and a benzene ring. They constitute a crucial structural unit of numerous bioactive compounds and natural products. Since the compounds containing benzimidaz
- Singh, Keisham S.,Joy, Francis,Devi, Prabha
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p. 181 - 190
(2020/11/26)
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- ZnO-NPs catalyzed condensation of 2-aminothiophenol and aryl/alkyl nitriles: Efficient green synthesis of 2-substituted benzothiazoles
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The synthesis of 2-substituted benzothiazoles has been described using ZnO-nanoparticles as a catalyst. The condensation of 2-aminothiophenol and aryl/alkyl nitriles resulted in the formation of various 2-substituted benzothiazoles under solvent-free reaction conditions. The library of 2-substituted benzothiazoles has been synthesized in good to excellent yield. The reaction has shown a wide range of functional group compatibility for both varyingly substituted 2-aminothiophenols and nitriles. The protocol has many advantages such as faster reaction rate, mild reaction conditions, various functional group compatibility, excellent yield, solvent-free reaction conditions, easy recovery of materials, and excellent catalyst recyclability, among others. The various advantages of this protocol make it a more feasible, economical, and environmentally benign process.
- Dhawale, Kiran D.,Ingale, Ajit P.,Shinde, Sandeep V.,Thorat, Nitin M.,Patil, Limbraj R.
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p. 1588 - 1601
(2021/03/18)
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- Pyrazole-Mediated C-H Functionalization of Arene and Heteroarenes for Aryl-(Hetero)aryl Cross-Coupling Reactions
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Herein we introduce a transition-metal-free protocol that involves a commercially available, inexpensive pyrazole molecule to conduct C-C cross-coupling reactions at room temperature via a radical pathway. Using this method, an aryldiazonium salt has been coupled to a wide range of arenes and heteroarenes including benzene, mesitylene, thiophene, furan, benzoxazole to result the corresponding biaryl products. The full reaction mechanism is elucidated along with the crystallographic probation of an active initiator species. A potassium-stabilized deprotonated pyrazole steers single-electron transfer to the substrate and behaves as an initiator for the reaction.
- Kundu, Abhishek,Dey, Dhananjay,Pal, Subhankar,Adhikari, Debashis
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p. 15665 - 15673
(2021/11/16)
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- Photocatalytic green synthesis of benzazoles from alcohol oxidation/toluene sp3C-H activation over metal-free BCN: effect of crystallinity and N-B pair exposure
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Porous borocarbonitride (P-BCN), with the characteristics of enhanced crystallinity and improved N-B pair exposure, was prepared with a simple KCl-assisted molten salt strategy. Efficient heterogeneous photocatalytic tandem synthesis of benzazoles from alcohol oxidation/toluene sp3C-H activation was achieved firstly over the metal-free P-BCN using visible light and the green oxidant O2, with only water as a by-product. Variouso-thio/hydroxy/aminoanilines and alcohols or toluenes could be converted to the corresponding 2-substituted benzothiazoles, benzoxazoles and benzimidazoles with good to excellent photocatalytic performance. The improved photocatalytic performance in comparison to bulk BCN should be due to the crystallinity-enhancement-induced improvement in charge separation and transmission. The increased N-B pair exposure promoted superoxide radical generation due to the electron-enriched N atoms, as well as improved oxidation ability due to the valence band constructed by the B 2p orbital. This work presents a green and efficient synthetic strategy towards benzazoles and other fine chemicalsviametal-free heterogeneous photocatalysis.
- Cheng, Hongmei,Gao, Xue,Jiang, Heyan,Sun, Bin,Zang, Cuicui
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p. 7955 - 7962
(2021/12/27)
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- "Metal-Free" Nanoassemblies of AIEE-ICT-Active Pyrazine Derivative: Efficient Photoredox System for the Synthesis of Benzimidazoles
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Supramolecular nanoassemblies of an AIEE-ICT-active pyrazine derivative (TETPY) having strong absorption in the visible region and excellent transportability have been utilized as an efficient photoredox catalytic system for the synthesis of a variety of benzimidazoles having electron-withdrawing/electron-releasing/aliphatic groups under "metal-free"conditions. The reaction protocol involves the successful harvesting of visible light by TETPY assemblies to catalyze the coupling of o-phenylenediamine/substituted diamines and substituted aromatic/heterocyclic/aliphatic aldehydes under aerial conditions using mixed aqueous media as the reaction solvent. TETPY assemblies could activate aerial oxygen to generate superoxide for completing the vital proton abstraction step without the need for any external metal/base/oxidant. Moreover, all the products are purified by recrystallization from organic solvents. The TETPY assemblies also exhibited high efficiency in catalyzing the synthesis of 2-substituted benzothiazoles and quinazolines in excellent yields.
- Dadwal, Shruti,Kumar, Manoj,Bhalla, Vandana
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p. 13906 - 13919
(2020/11/20)
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- MWCNTs-ZrO2 as a reusable heterogeneous catalyst for the synthesis of N-heterocyclic scaffolds under green reaction medium
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A simple, efficient, and facile heterogeneous multi-walled carbon nanotubes-zirconia nanocomposite (MWCNTs-ZrO2) has been synthesized using natural feedstock coconut juice (água-de-coco do Ceará). The synthesized catalyst was characterized by Fourier transform infrared spectroscopy, X-ray diffraction, field emission scanning electron microscopy, and X-ray photoelectron spectroscopy analysis. The heterogeneous nanocomposite has been used for one-pot synthesis of various N-heterocyclic compounds like pyrazoles, 1,2-disubstituted benzimidazoles, 2-arylbenzazoles, and 2,3-dihydroquinazolin-4(1H)-ones under green reaction medium at room temperature. This novel method has several advantages, such as short reaction time, simple work-up, excellent yield, and green reaction conditions. The catalyst was recycled up to four times without significant loss in catalytic activity.
- Halder, Bipasa,Banerjee, Flora,Nag, Ahindra
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- Sulfamic acid-catalyzed conversion of o-aminothiophenol and aromatic aldehydes to 2-arylbenzothiazoles
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Non-metallic, non-toxic, and cheap sulfamic acid was used as a catalyst for the synthesis of 2-arylbenzothiazole from o-aminothiophenol and aromatic aldehydes bearing electron-donating or electron-withdrawing groups. The sulfamic acid catalyst can be reus
- Shi, Chunjie,Song, Renyuan,Wang, Guangrong,Yu, Xiaofeng
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p. 871 - 879
(2020/09/09)
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- Nanoporous Cu doped ZnS nanoparticles an efficient photo catalyst for the chemoselective synthesis of 2-substituted azoles via C-N arylation/ CSp3– H oxidation/ cyclization/dehydration sequence in visible light
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ZnS and Cu:ZnS nanoparticles were prepared by aqueous chemical method and characterized by several analytical tools. Nanoparticles have an average size of about ~ 18 nm and possess highly open mesopores, moderate surface area, and uniform morphology. UV–vis spectra designate that doping of Cu shifted the optical response of the ZnS nanoparticles in to a visible region. These Cu:ZnS nanoparticles were employed as a photocatalyst for chemoselective synthesis of 2-substituted azoles by the reaction of benzyl bromides and 1,2-Diaminobenzene or 2-Mercaptoaniline in visible light. Analogous experiments confirmed that the reaction were proceeds through one pot C–N arylation/ CSp3– H oxidation/ cyclization/dehydration sequence. The enhanced catalytic activity by doping could be attributed to the presence of trapping level generated by copper doping which augments the relaxation time of electron and holes so that they are easily available for the reaction. The method was also applicable for the synthesis of quinazolin-4(3H)-ones.
- Dandia, Anshu,Bansal, Sarika,Sharma, Ruchi,Kumar Mahawar, Dinesh,Rathore, Kuldeep S.,Lal Meena, Mohan,Parewa, Vijay
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- Nickel catalysed construction of benzazoles: Via hydrogen atom transfer reactions
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Herein we report a homogeneous, phosphine free, inexpensive nickel catalyst that forms a wide variety of benzazoles from alcohol and diamines by a reaction sequence of alcohol oxidation, imine formation, ring cyclization and dehydrogenative aromatization. A reversible azo/hydrazo couple, that is part of the ligand architecture steers both the alcohol oxidation and dehydrogenation of the annulated amine under fairly mild reaction conditions. Interestingly, both the alcohol oxidation and amine dehydrogenation steps are directly mediated by hydrogen atom transfer (HAT), which is greatly facilitated by the reduced ligand backbone. The kH/kD for the amine dehydrogenation step, measured at 60 °C is 5.9, fully consistent with HAT as the rate determining factor during this step. This is a unique scenario where two consecutive oxidation steps towards benzazole formation undergo HAT, which has been substantiated via kinetic studies, KIE determination and intermediate isolation. This journal is
- Adhikari, Debashis,Bains, Amreen K.,Dey, Dhananjay,Kundu, Abhishek,Yadav, Sudha
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p. 6495 - 6500
(2020/11/13)
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- Method for synthesizing benzothiazole by microwave radiation of benzothioamide compound in aqueous phase
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The invention discloses a method for synthesizing benzothiazole by microwave radiation of a benzothioamide compound in an aqueous phase. The method includes the steps: adding the benzothioamide compound into the aqueous phase under microwave conditions; performing cyclization under alkaline conditions to generate the benzothiazole. The method for preparing the benzothiazole is environmentally friendly, simple and convenient in operation, safe, cheap and efficient. Compared with the prior art, the method is applicable to a lot of functional groups, high in yield, few in by-products, simple in operation, safe, low in cost and environmentally friendly.
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Paragraph 0013; 0044
(2019/02/13)
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- Method used for rapid preparation of benzo-heterocycle compound with physical grinding under solvent-free room temperature conditions
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The invention discloses a method used for rapid preparation of benzo-heterocycle compound with physical grinding under solvent-free room temperature conditions. According to the method, glacial aceticacid is taken as a catalyst; at solvent-free room temperature conditions, physical grinding is adopted, reaction of 2-substituted arylamines (2-mercapto arylamine, 2-aminophenol, and o-phenylenediamine) and aromatic aldehydes is carried out using physical grinding. The method is friendly to the environment, is simple in operation, is safe, is low in cost, and is high in efficiency. Compared withthe prior art, the advantages are that: the method is suitable for a large amount of functional groups, yield is high, less by-product is generated, operation is simple, the method is safe, cost is low, and the method is friendly to the environment.
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Paragraph 0062; 0130
(2019/01/21)
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- Synthesis method of 2-substituted benzoxazole, 2-substituted benzothiazole and derivatives thereof
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The invention provides a synthesis method of 2-substituted benzoxazole, 2-substituted benzothiazole and derivatives thereof. In the method, through ortho-aminophenol/2-aminothiophenol cyclization catalyzed by imidazole hydrochloride, synthesis of functionalized 2-substituted benzoxazole and 2-substituted benzothiazole is realized; the method is simple, economical and high in practicality. No othercatalysts or additives are used, the synthesis method ensures good functional group tolerance and excellent yield and purity, the reaction time is short, no harsh reaction conditions are needed, andthe method is suitable for industrial production.
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Paragraph 0047; 0052; 00054-0055
(2019/02/10)
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- A Multi-step Virtual Screening Protocol for the Identification of Novel Non-acidic Microsomal Prostaglandin E2 Synthase-1 (mPGES-1) Inhibitors
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Microsomal prostaglandin E2 synthase-1 (mPGES-1) is a potential therapeutic target for the treatment of inflammatory diseases and certain types of cancer. To identify novel scaffolds for mPGES-1 inhibition, we applied a virtual screening (VS) p
- Shekfeh, Suhaib,?al??kan, Burcu,Fischer, Katrin,Yal??n, Tansu,Garscha, Ulrike,Werz, Oliver,Banoglu, Erden
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supporting information
p. 273 - 281
(2019/01/04)
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- TBHP/KI-Promoted Annulation of Anilines, Ethers, and Elemental Sulfur: Access to 2-Aryl-, 2-Heteroaryl-, or 2-Alkyl-Substituted Benzothiazoles
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An efficient TBHP/KI-promoted annulation of anilines with ethers and elemental sulfur has been developed through the selective C-O bond cleavage of ethers under transition-metal-free conditions. A wide range of 2-aryl-, 2-heteroaryl-, and 2-alkyl-substituted benzothiazoles were easily prepared with satisfactory yields and good functional group compatibility.
- Zhang, Jie,Zhao, Xin,Liu, Ping,Sun, Peipei
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p. 12596 - 12605
(2019/10/11)
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- Iridium-catalyzed intramolecular C–N and C–O/S cross-coupling reactions: Preparation of benzoazole derivatives
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The irdium-catalyzed intramolecular arylcarbon-hetero cross-coupling reactions with o-haloarylamides or o-haloarylamidine have been effectively achieved using KOAc and just 1 mol% catalyst. The [Ir(cod)Cl]2 was proved to be more potential for smoothly assembling functional structures benzimidazoles, benzoxazoles and benzothiazoles, which was superior to Cu- and Pd-catalyzed systems. Simultaneously, a concise and efficient synthesis of tafamidis was developed in 5-g scale.
- Shi, Yajie,Zhou, Qifan,Du, Fangyu,Fu, Yang,Du, Yang,Fang, Ting,Chen, Guoliang
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- Copper supported on functionalized MCM-41 as a novel and a powerful heterogeneous nanocatalyst for the synthesis of benzothiazoles
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A new functionalized mesoporous catalyst (Cu(II)-Glycerol/MCM-41) has been synthesized as a highly efficient heterogeneous nanocatalyst for the synthesis of benzothiazoles derivatives. Powder XRD, TGA, TEM, SEM, EDX, BET, FT-IR and ICP-OES techniques are
- Noroozi Pesyan, Nader,Batmani, Hana,Havasi, Forugh
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p. 248 - 254
(2018/11/26)
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- A novel ternary GO@SiO2-HPW nanocomposite as an efficient heterogeneous catalyst for the synthesis of benzazoles in aqueous media
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A new solid acid catalyst, consisting of 12-phosphotungstic heteropoly acid (HPW) supported on graphene oxide/silica nanocomposite (GO@SiO2), has been developed via immobilizing HPW onto an amine-functionalized GO/SiO2 surface through coordination interaction (GO@SiO2-HPW). The GO@SiO2-HPW nanocomposite was characterized by Fourier transform infrared (FT-IR) spectroscopy, thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and powder X-ray diffraction (XRD). The prepared nanocomposite could be dispersed homogeneously in water and further used as a heterogeneous, reusable, and efficient catalyst for the synthesis of benzimidazoles and benzothiazoles by the reaction of 1,2-phenelynediamine or 2-aminothiophenol with different aldehydes.
- Habibzadeh, Setareh,Firouzzadeh Pasha, Ghasem,Tajbakhsh, Mahmood,Amiri Andi, Nasim,Alaee, Ehsan
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p. 934 - 944
(2019/06/13)
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- Metal-free selective synthesis of 2-substituted benzimidazoles catalyzed by Br?nsted acidic ionic liquid: Convenient access to one-pot synthesis of N-alkylated 1,2-disubstituted benzimidazoles
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A novel efficient method for the selective synthesis of 2-substituted benzimidazoles is described through condensation reaction of o-phenylenediamines with a wide rang of aliphatic, aromatic and heteroaromatic aldehyde substrates using Br?nsted acidic ionic liquid as a reusable catalyst under metal-free conditions at ambient temperature. Notably, Dodecylimidazolium hydrogen sulfate ([DodecIm][HSO4]) is the most efficient catalyst for good to excellent yields of the corresponding products (up to 98%). Subsequently, this protocol was successfully applied for the preparation of N-alkylated 1,2-disubstituted benzimidazoles in high to excellent yields via sequential one-pot reaction. In addition, catalysts are recycled at least four times without significant loss in activity.
- Senapak, Warapong,Saeeng, Rungnapha,Jaratjaroonphong, Jaray,Promarak, Vinich,Sirion, Uthaiwan
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p. 3543 - 3552
(2019/05/29)
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- Silica-supported zinc chloride (ZnCl2/SiO2)-induced efficient protocol for the synthesis of N-sulfonyl imines and 2-Arylbenzothiazole
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A straightforward strategy for the synthesis of N-sulfonyl imine derivatives from sulfonamides and aryl aldehydes utilizing Silica-supported zinc chloride (ZnCl2/SiO2, silzic) as a catalyst under solvent-free conditions has been developed. 2-Arylbenzothiazole derivatives were also synthesized by the reaction of 2-aminothiophenol with aryl aldehydes under the same conditions. This procedure has advantages of high yields, mild reaction condition, simple procedure, low cost, and simplicity of workup. The catalyst has the same efficiency on its reuse up to three times.
- Soliman, Hanan A.,El-Shahat, Mahmoud,Soliman, Abdel-Ghany
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p. 584 - 591
(2019/07/31)
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- Virtual screening identification and chemical optimization of substituted 2-arylbenzimidazoles as new non-zinc-binding MMP-2 inhibitors
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Matrix metalloproteinases (MMPs) are a large family of zinc-dependent endoproteases known to exert multiple regulatory roles in tumor progression and invasiveness. This encouraged over the years the approach of MMP, and particularly MMP-2, targeting for anticancer treatment. Early generations of MMP inhibitors, based on aspecific zinc binding groups (ZBGs) assembled on (pseudo)peptide scaffolds, have been discontinued due to the clinical emergence of toxicity and further drawbacks, giving the way to inhibitors with alternative zinc-chelator moieties or not binding the catalytic zinc ion. In the present paper, we continue the search for new non-zinc binding MMP-2 inhibitors: exploiting previously identified compounds, a virtual screening (VS) campaign was carried out and led to the identification of a new class of ligands. The structure-activity relationship (SAR) of the benzimidazole scaffold was explored by synthesis of several analogues whose inhibition activity was tested with enzyme inhibition assays. By performing the molecular simplification approach, we disclosed different sets of single-digit micromolar inhibitors of MMP-2, with up to a ten-fold increase in inhibitory activity and ameliorated selectivity towards off-target MMP-8, compared to selected lead compound. Molecular dynamics calculations conducted on complexes of MMP-2 with docked privileged structures confirmed that analyzed inhibitors avoid targeting the zinc ion and dip inside the S1′ pocket. Present results provide a further enrichment of our insights for the design of novel MMP-2 selective inhibitors.
- Agamennone, Mariangela,Caradonna, Alessia,Di Pizio, Antonella,Laghezza, Antonio,Loiodice, Fulvio,Luisi, Grazia,Piemontese, Luca,Tortorella, Paolo
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- Peroxide-mediated oxidative coupling of primary alcohols and disulfides: Synthesis of 2-substituted benzothiazoles
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A peroxide-mediated protocol for the synthesis of 2-substituted benzothiazoles was developed, starting from bis(o-aminophenyl) disulfides and primary alcohols. Eleven differently 2-substituted benzothiazoles were prepared in moderate to excellent yields using di-tert-butyl peroxide (DTBP) as an oxidant.
- Padilha, Nathalia B.,Penteado, Filipe,Salom?o, Maria C.,Lopes, Eric F.,Bettanin, Luana,Hartwig, Daniela,Jacob, Raquel G.,Lenard?o, Eder J.
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supporting information
p. 1587 - 1591
(2019/05/21)
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- Eco-friendly syntheses of 2-substituted benzoxazoles and 2-substituted benzothiazoles from 2-aminophenols, 2-aminothiophenols and DMF derivatives in the presence of imidazolium chloride
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A simple, economical and metal-free approach to the synthesis of 2-substituted benzoxazoles and 2-substituted benzothiazoles from 2-aminophenols, 2-aminothiophenols and DMF derivatives, only using imidazolium chloride (50% mmol) as promoter without any other additive, was reported. Various 2-substituted benzoxazoles and 2-substituted benzothiazoles were thus prepared in moderate to excellent yields.
- Tian, Qingqiang,Luo, Wen,Gan, Zongjie,Li, Dan,Dai, Zeshu,Wang, Huajun,Wang, Xuetong,Yuan, Jianyong
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supporting information
(2019/01/21)
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- Synthesis and characterization of a new poly(N–heterocyclic carbene Cu complex) immobilized on nano–silica, (CuII–NHCs)n@nSiO2, and its application as an efficient and reusable catalyst in the synthesis of benzimidazoles,
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The present study describes the synthesis and characterization of a new poly(N–heterocyclic carbene Cu complex) immobilized on nano silica, (CuII–NHCs)n@nSiO2. The (CuII–NHCs)n@nSiO2 dendri
- Khajehzadeh, Mostafa,Moghadam, Majid,Jamehbozorgi, Saeed
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p. 173 - 189
(2018/10/21)
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- A New Pathway to 2-Arylbenzoxazoles and 2-Arylbenzothiazoles Via One-Pot Oxidative Cyclization Reactions Under Iron-Organic Framework Catalysis
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Iron-organic framework MOF-235 was synthesized, and consequently utilized as a productive heterogeneous catalyst for the synthesis of 2-arylbenzoxazoles and 2-arylbenzothiazoles via one-pot oxidative cyclization reactions between 2-aminophenols or 2-aminothiophenols and alcohols. The transformation was considerably controlled by the oxidant and the nature of solvent, and the system of di-tert-butylperoxide with xylene led to best yield of major products. The MOF-235 catalyst presented higher catalytic efficiency for the synthesis of 2-arylbenzoxazoles and 2-arylbenzothiazoles than a number of MOF-based catalysts and established homogeneous catalysts. Recovering and reutilizing the framework catalyst for the cyclization transformation was possible while its catalytic activity was retained. To the best of our knowledge, this iron-catalyzed one-pot oxidative transformation to produce 2-arylbenzoxazoles and 2-arylbenzothiazoles under heterogeneous catalysis conditions was not previously reported in the literature.
- Doan, Son H.,Tran, Chau B.,Cao, An. L. N.,Le, Nhan T. H.,Phan, Nam T. S.
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p. 2053 - 2063
(2019/04/25)
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- Method for preparing benzothiazole compound through microwave catalysis in water phase
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The invention discloses a method for preparing a benzothiazole compound through/under microwave catalysis in a water phase. A water-soluble coordination compound is used as a catalyst, and a reactionof inorganic sulfide, 2-iodoaniline and aldehyde is efficiently catalyzed through microwaves in a pure water phase. The method for preparing the benzothiazole compound is environmentally friendly, convenient to operate, safe, cheap and efficient. Compared with the prior art, the method is applied to a large quantity of functional groups, high in yield, simple to operate, safe, low in cost and environmentally friendly and produces a few byproducts.
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Paragraph 0016; 0018
(2018/05/16)
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- NH3(CH2)5NH3BiCl5: an efficient and recyclable catalyst for the synthesis of benzoxazole, benzimidazole and benzothiazole heterocycles
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In this work, the condensation of aromatic aldehydes with different two-substituted aniline catalyzed by NH3(CH2)5NH3BiCl5 as heterogeneous and recyclable catalyst was reported. It was demonstrated that NH3(CH2)5NH3BiCl5 can act as an efficient and active catalyst and is reusable for six runs without a significant loss of their catalytic activity. Simple preparation of the catalyst, high catalytic activity and good reusability are noteworthy advantages of this catalytic system in the synthesis of benzoxazole, benzimidazole and benzothiazole heterocycles at room temperature under solvent-free conditions.
- Benzekri, Zakaria,Sibous, Sara,Serrar, Houda,Ouasri, Ali,Boukhris, Said,Rhandour, Ali,Souizi, Abdelaziz
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p. 2781 - 2787
(2018/10/31)
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- Solid Acid Supported on Magnetic Nanoparticles as a Highly Efficient and Retrievable Catalyst for the Synthesis 2-Substituted Benzothiazoles
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The use of a recyclable heterogeneous nanomagnetic solid acid catalyst, [Fe3O4@SiO2@(CH2)3NPC–SO3H]Cl, in a simple and highly efficient synthesis of benzothiazole derivatives by the reactio
- Gorjizadeh,Sayyahi
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p. 1899 - 1903
(2018/11/24)
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- A modern and practical laccase-catalysed route suitable for the synthesis of 2-arylbenzimidazoles and 2-arylbenzothiazoles
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Heterocyclic aromatic compounds containing an imine (C═N) bond such as benzimidazoles and benzothiazoles are important active pharmaceutical ingredients. The synthesis of 2-aryl-1H-benzimidazoles and 2-arylbenzothiazoles in good to excellent yields was ac
- Maphupha, Mudzuli,Juma, Wanyama P.,De Koning, Charles B.,Brady, Dean
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p. 39496 - 39510
(2018/12/13)
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- Phosphonium acidic ionic liquid: An efficient and recyclable homogeneous catalyst for the synthesis of 2-Arylbenzoxazoles, 2-Arylbenzimidazoles, and 2-Arylbenzothiazoles
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A highly efficient and green strategy for the synthesis of 2-Arylbenzoxazoles, 2-Arylbenzimidazoles, and 2-Arylbenzothiazoles catalyzed by phosphonium acidic ionic liquid has been developed via the condensation of o-Aminophenol, o-phenylenediamines, and o-Aminothiophenol, respectively, with aldehydes. The reaction has a good yield, the broad substrate scope, and mild condition. Triphenyl(butyl-3-sulphonyl)phosphonium toluenesulfonate catalyst was easily obtained from cheap and available starting materials through a one-pot synthesis. Its structure was identified by 1H NMR, 13C NMR, 31P NMR, and FT-IR techniques. Other properties including thermal stability and acidity were determined by TGA and Hammett acidity function method. Interestingly, the catalyst can maintain its constantly outstanding performance till the fourth recovery.
- Nguyen, Quang The,Thi Hang, Anh-Hung,Ho Nguyen, Thuy-Linh,Nguyen Chau, Duy-Khiem,Tran, Phuong Hoang
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p. 11834 - 11842
(2018/04/05)
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- Deep eutectic solvent-catalyzed arylation of benzoxazoles with aromatic aldehydes
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A novel and efficient methodology for the arylation of benzoxazoles with aromatic aldehydes catalyzed by deep eutectic solvent has been developed. The reaction smoothly proceeded with a wide range of substrates to give the desired products in high yields within short reaction time. Deep eutectic solvents are easily recovered and reused without significant loss of catalytic activity.
- Tran, Phuong Hoang,Thi Hang, Anh-Hung
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p. 11127 - 11133
(2018/03/26)
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- One-pot synthesis of benzoazoles via dehydrogenative coupling of aromatic 1,2-diamines/2-aminothiophenol and alcohols using Pd/Cu-MOF as a recyclable heterogeneous catalyst
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In this paper we report an efficient synthetic approach for the preparation of the widespread numbers of benzoazoles via dehydrogenative coupling of 1,2-phenylenediamine or 2-aminothiophenol and benzyl alcohols by Pd/Cu2(BDC)2(DABCO)-MOF as new heterogeneous catalyst under solvent-free condition. The catalyst recycled and reused for four times without loss of catalytic activity. The structures of benzoazoles were corroborated spectroscopically (1H- and 13C NMR, and elemental analysis) and were confirmed by comparison with reference compounds. A plausible mechanism for this type of reaction is proposed.
- Mokhtari, Javad,Hasani Bozcheloei, Abolfazl
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supporting information
p. 726 - 731
(2018/07/25)
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- Facile Protocols towards C2-Arylated Benzoxazoles using Fe(III)-Catalyzed C(sp 2 -H) Functionalization and Metal-Free Domino Approach
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Considering their growing attention in the field of medicinal chemistry and drug-discovery research, the facile and convenient approaches towards the preparation of 2-aryl benzoxazole derivatives have been described. The transformation is accomplished by using Fe(III)-catalyzed C-H activation of benzoxazoles with boronic acids to obtain a wide range of C2-arylated benzoxazoles in high yields. The developed method excludes the formation of self-coupling compounds as side products. On the other hand, the synthesis of the products is also achieved via a metal-free domino protocol by the reaction between 1-nitroso-2-naphthol and acetophenones using catalytic amounts of CBr 4 in the presence of Cs 2 CO 3 as base. The devised tandem method avoids the use of pre-activated α-haloketones as substrates. Due to their immense impact in marketed drugs and molecules under clinical trial, the described method can be a powerful tool for their synthesis which restricts the use of precious metals as catalyst.
- Vodnala, Nagaraju,Gujjarappa, Raghuram,Kabi, Arup K.,Kumar, Mohan,Beifuss, Uwe,Malakar, Chandi C.
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supporting information
p. 1469 - 1478
(2018/05/25)
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- Unprecedented salt-promoted direct arylation of acidic sp2 C[sbnd]H bonds under heterogeneous Ni-MOF-74 catalysis: Synthesis of bioactive azole derivatives
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Herein, nickel-based metal-organic framework, Ni-MOF-74, was synthesized by a solvothermal method and its properties was characterized by a host of techniques. Ni-MOF-74 exhibited exceptional catalytic activity toward the direct arylation of azoles via C[sbnd]H activation while other Ni-MOFs, nickel-based heterogeneous systems, and homogeneous counter parts displayed lower activity. Optimal conditions involved the use of Li2CO3 or KCl salts in diglyme solvent in 18 h and no additional ligand is required. This is the first and unprecedented report using KCl salt as promoter for arylation of heterocycles. By avoiding the use of strong bases and oxidants, optimized conditions are compatible with wide range of functional groups and heterocycles. Furthermore, by taking advantage of large aperture size of Ni-MOF-74, we are able to utilize optimized conditions to successfully synthesize several bioactive arylated azole derivatives. Previous studies using heterogeneous catalysts to approach these bioactive compounds are not performed in the literature. Leaching tests indicated that homogeneous catalysis via leached active nickel species is unlikely. Thus, the catalyst was facilely separated from the reaction mixture and reused several times without significant degradation of the catalytic reactivity.
- Nguyen, Huong T.T.,Doan, Duc N.A.,Truong, Thanh
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p. 141 - 149
(2016/12/09)
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- Development of (quinolinyl)amido-based pincer palladium complexes: A robust and phosphine-free catalyst system for C-H arylation of benzothiazoles
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(Quinolinyl)amido-ligated palladium(ii) complexes have been synthesized and applied in the catalytic C-H bond arylation of benzothiazoles. The tridentate ligand precursors R2N-C(O)CH2-(NH)-C9H6N [(R2NNN8-Q)-H; R2N = morpholinyl, Me-N-piperazinyl] and the pincer palladium complexes [κN,κN,κN-{R2N-C(O)CH2-(μ-N)-C9H6N}]PdX [(R2NNN8-Q)PdX {R2N = Et2N, morpholinyl, Me-N-piperazinyl; X = OAc or Cl}] were efficiently synthesized, and characterized by various analytical techniques. The iodo derivative (Et2NNN8-Q)PdI was obtained in excellent yield by the treatment of the complex (Et2NNN8-Q)PdCl with KI. The molecular structures of complexes (Et2NNN8-Q)Pd(OAc) (2a), (Et2NNN8-Q)PdCl (3a) and (Et2NNN8-Q)PdI (4a) were elucidated by X-ray crystallography. Complex 3a was found to be the most efficient catalyst for direct C-H bond arylation of substituted benzothiazoles with diverse aryl iodides using a mild base, K2CO3. The working catalyst system 3a is highly robust and can be recycled and reused several times for the arylation of benzothiazole without loss of catalytic activity. Preliminary mechanistic investigations using controlled studies and kinetic analysis have been performed, which greatly support a molecular mechanism for the arylation.
- Pandiri, Hanumanprasad,Soni, Vineeta,Gonnade, Rajesh G.,Punji, Benudhar
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p. 3543 - 3554
(2017/07/12)
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- NaY Zeolite Functionalized by Sulfamic Acid/Cu(OAc)2 as a Novel and Reusable Heterogeneous Hybrid Catalyst in Efficient Synthesis of Bis, Tris, and Tetrakis(indolyl)methanes, 3,4-Dihydropyrimidin-2(1H)-ones, and 2-Aryl-1H-benzothiazoles
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An efficient acid-catalyzed synthesis of some bis, tris, and tetrakis(indolyl)methanes, 3,4-dihydropyrimidin-2(1H)-ones, and 2-aryl-1H-benzothiazoles is reported using NaY zeolite functionalized by sulfamic acid/Cu(OAc)2 (NaY zeolite-NHSO3
- Kazemi, Samira,Mobinikhaledi, Akbar,Zendehdel, Mojgan
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p. 764 - 776
(2017/07/25)
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- A green approach to the synthesis of a nano catalyst and the role of basicity, calcination, catalytic activity and aging in the green synthesis of 2-aryl bezimidazoles, benzothiazoles and benzoxazoles
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A green synthesis of hydrotalcite (a double layered catalyst) by a grinding method using Al/Mg molar ratios of 1.0-3.0 at room temperature is described. The prepared double layered catalyst (hydrotalcite) has been characterized by TG, FT-IR, SEM, XRD and Hammett titration methods. Different factors such as the effect of molar ratios, catalyst loading, reaction time, aging time, and basicity have been investigated for the facile, efficient and green synthesis of 2-arylbenzimidazoles, benzothiazoles and benzoxazoles under solvent free conditions. The influence of catalyst loading on reactivity was studied and a catalyst loading of 20 mg was found to be optimal, giving the best yield with minimum time as compared to other catalysts. The present methodology reports, herein, a rapid and cost effective synthesis of hydrotalcite and its versatile applications in the synthesis of 2-arylbenzimidazoles, benzothiazoles and benzoxazoles.
- Sahu, Pramod K.
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p. 42000 - 42012
(2017/09/12)
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- Green and Highly Efficient Synthesis of Mono- and Bis-Benzothiazoles in the Presence of Fe(SD)3 under Ultrasound Irradiation
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A convenient, practical, green, and environmentally friendly method was developed for the synthesis of benzothiazoles from 2-aminothiophenol and various aldehydes. Bis-benzothiazoles were synthesized in high yield under mild reaction conditions. Products
- Pirbasti, Fateme Ghanbari,Mahmoodi, Nosrat Ollah
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- Synthesis of some benzothiazoles by developing a new protocol using urea nitrate as a catalyst and their antimicrobial activities
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The present communication demonstrates the development of urea nitrate as an effective and efficient catalyst for the synthesis of some 2-substituted benzothiazoles. Instant progress of reaction at room temperature under solvent-free condition, very high catalytic activity, inexpensive, clean reaction profile, operational simplicity, large-scale synthesis and appreciable yields are the main advantages of this protocol. These synthesized benzothiazoles have been evaluated for their antibacterial and antifungal activities against Gram-positive bacterium (Bacillus subtilis MTCC 121); two Gram-negative bacteria (Escherichia coli MTCC 1652 and Pseudomonas aeruginosa MTCC 741) and two fungi (Candida albicans MTCC 3017 and Saccharomyces cerevisiae MTCC 170). Compound 3n was found the most active against all the tested microbes.
- Kumar, Parvin,Bhatia, Rimpy,Khanna, Radhika,Dalal, Aarti,Kumar, Dinesh,Surain, Parveen,Kamboj, Ramesh C.
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p. 585 - 596
(2017/10/05)
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