- Synthesis of a conformationally constrained analogue of BW A78U, an anticonvulsant adenine derivative
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The synthesis of a conformationally constrained analogue of the anticonvulsant BW A78U, a 9-benzyl-adenine derivative, has been devised, using silicon tetrachloride in a new cyclodehydration.
- Desaubry, Laurent,Wermuth, Camille Georges,Bourguignon, Jean-Jacques
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- Synthesis, Structure, and Luminescent Property of One Zinc(II) Coordination Polymer Constructed from 1H-Benzoimidazole
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A new metal-organic coordination polymer [Zn(bm)(AcO)]n (1), where Hbm is 1H-benzoimidazole), has been prepared and structurally characterized by IR, elemental analysis and single-crystal X-ray diffraction. Single-crystal X-ray analysis shows that it crystallizes in the monoclinic space group of P21/c with a = 10.8231(5) ?, b = 9.8329(4) ?, c = 8.8665(4) ?, β = 99.298(4)°, V = 931.20(7) ?3, and X = 4. The bm ligand bridges two adjacent Zn(II) with its two nitrogen atoms to form a one-dimensional chain, which further constructed 2D network through a bridge bidentate AcO- ligand. Furthermore, luminescent property of 1 was investigated.
- Zhang, Shu Hua,Zhao, Ru Xia,Li, Gui,Zhang, Hai Yang,Li, He Ping
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- UV monitoring of microwave-heated reactions - A feasibility study
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UV/Visible spectroscopy has been used to monitor the progress of the formation of benzimidazole from the reaction between 1,2-diaminobenzene and formic acid. The reaction was performed at three concentration levels, each becoming more dilute so that at the most dilute level direct UV monitoring from the reaction sample was possible. At each level the reaction was conducted by conventional and by microwave heating. The success of the microwave reaction at the most dilute levels encourages the construction of a microwave reactor/UV/Vis spectrometer hybrid instrument for the monitoring of this and other reactions.
- Getvoldsen, Gareth S.,Elander, Nils,Stone-Elander, Sharon A.
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- Haloacetylated enol ethers. 13 [19]. Synthesis of N-[1-aryl(alkyl)-3- oxo-4,4,4-trichloro-1-buten-1-yl]-o-phenylenediamines and 2-trichloromethyl- 4-aryl-3H-1,5-benzodiazepines
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The synthesis and isolation of the intermediates N-[1-aryl(alkyl)-3- oxo-4,4,4-trichloro-1-buten-1-yl]-o-phenylenediamines 2a-f and the corresponding 2-trichloromethyl-4-aryl-3H-1,5-benzodiazepines 3c-g or benzimidazoles 4a-b derivatives obtained from the intramolecular cyclization of 2a-f or from direct cyclocondensation reaction of β-alkoxyvinyl trichloromethyl ketones 1a-g with o-phenylenediamine, is reported. Depending of the structure of the β-alkoxyvinyl trichloromethyl ketones or the N-[1- aryl(alkyl)-3-oxo-4,4,4-trichloro-buten-1-yl]-o-phenylenediamines and the reactions conditions, benzimidazoles or 3H-1,5-benzodiazepines were obtained.
- Bonacorso, Helio Gauze,Bittencourt, Sandra R. T.,Wastowski, Arci D.,Wentz, Alexandre P.,Zanatta, Nilo,Martins, Marcos A. P.
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- One-Pot Transformation of Lignin and Lignin Model Compounds into Benzimidazoles
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It is a challenging task to simultaneously achieve selective depolymerization and valorization of lignin due to their complex structure and relatively stable bonds. We herein report an efficient depolymerization strategy that employs 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) as oxidant/catalyst to selectively convert different oxidized lignin models to a wide variety of 2-phenylbenzimidazole-based compounds in up to 94 % yields, by reacting with o-phenylenediamines with varied substituents. This method could take full advantage of both Cβ and/or Cγ atom in lignin structure to furnish the desirable products instead of forming byproducts, thus exhibiting high atom economy. Furthermore, this strategy can effectively transform both the oxidized hardwood (birch) and softwood (pine) lignin into the corresponding degradation products in up to 45 wt% and 30 wt%, respectively. Through a “one-pot” process, we have successfully realized the oxidation/depolymerization/valorization of natural birch lignin at the same time and produced the benzimidazole derivatives in up to 67 wt% total yields.
- Guo, Tao,He, Jianghua,Liu, Tianwei,Zhang, Yuetao
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supporting information
(2022/02/07)
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- Sulfoxylate Anion Radical-Induced Aryl Radical Generation and Intramolecular Arylation for the Synthesis of Biarylsultams
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Aryl radical generation from the corresponding aryl halides using an electron donor and subsequent intramolecular cyclization with arenes could be an important advancement in contemporary biaryl synthesis. A green and practically useful synthetic protocol to access diverse six- and seven-membered biarylsultams especially with a free NH group including demonstration of a gram-scale synthesis is reported herein. The sulfoxylate anion radical (SO2-?), generated in situ from the reagents rongalite or sodium dithionite (Na2S2O4), was found to be the key single electron transfer agent forming aryl radicals from aryl halides, which upon intramolecular arylation gives biarylsultams with good to excellent yields. The approach features generation of aryl radicals that remained underexplored, use of a cheap and readily available industrial reagents, and transition metal-free, mild, and green reaction conditions.
- Laha, Joydev K.,Gupta, Pankaj
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supporting information
p. 4204 - 4214
(2022/03/16)
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- Facile N-Formylation of Amines on Magnetic Fe3O4?CuO Nanocomposites
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A facile, eco-friendly, efficient, and recyclable heterogeneous catalyst is synthesized by immobilizing copper impregnated on mesoporous magnetic nanoparticles. The surface chemistry analysis of Fe3O4?CuO nanocomposites (NCs) by XRD and XPS demonstrates the synergistic effect between Fe3O4 and CuO nanoparticles, providing mass-transfer channels for the catalytic reaction. TEM images clearly indicate the impregnation of CuO onto mesoporous Fe3O4. This hydrothermally synthesized eco-friendly and highly efficient Fe3O4?CuO NCs are applied as a magnetically retrievable heterogeneous catalyst for the N-formylation of wide range of aliphatic, aromatic, polyaromatic and heteroaromatic amines using formic acid as a formylating agent at room temperature. The catalytic activity of the NCs for N-formylation is attributable to the synergistic effect between Fe3O4 and CuO nanoparticles. The N-formylated product is further employed for the synthesis of biologically active quinolone moieties.
- Datta Khanal, Hari,Mishra, Kanchan,Rok Lee, Yong
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p. 4477 - 4484
(2021/08/30)
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- Discovery of amide-functionalized benzimidazolium salts as potent α-glucosidase inhibitors
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α-Glucosidase inhibitors (AGIs) are used as medicines for the treatment of diabetes mellitus. The α-Glucosidase enzyme is present in the small intestine and is responsible for the breakdown of carbohydrates into sugars. The process results in an increase in blood sugar levels. AGIs slow down the digestion of carbohydrates that is helpful in controlling the sugar levels in the blood after meals. Among heterocyclic compounds, benzimidazole moiety is recognized as a potent bioactive scaffold for its wide range of biologically active derivatives. The aim of this study is to explore the α-glucosidase inhibition ability of benzimidazolium salts. In this study, two novel series of benzimidazolium salts, i.e., 1-benzyl-3-{2-(substituted) amino-2-oxoethyl}-1H-benzo[d]imidazol-3-ium bromide 9a–m and 1-benzyl-3-{2-substituted) amino-2-oxoethyl}-2-methyl-1H-benzo[d] imidazol-3-ium bromide 10a–m were screened for their in vitro α-glucosidase inhibitory potential. These compounds were synthesized through a multistep procedure and were characterized by1H-NMR,13C-NMR, and EI-MS techniques. Compound 10d was identified as the potent α-glucosidase inhibitor among the series with an IC50 value of 14 ± 0.013 μM, which is 4-fold higher than the standard drug, acarbose. In addition, compounds 10a, 10e, 10h, 10g, 10k, 10l, and 10m also exhibited pronounced potential for α-glucosidase inhibition with IC50 value ranging from 15 ± 0.037 to 32.27 ± 0.050 μM when compared with the reference drug acarbose (IC50 = 58.8 ± 0.12 μM). A molecular docking study was performed to rationalize the binding interactions of potent inhibitors with the active site of the α-glucosidase enzyme.
- Ahmad, Matloob,Ashfaq, Usman Ali,Khan, Imran Ahmad,Sultan, Sadia,Zaki, Magdi E. A.
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- Efficiency enhancement with chloride to iodide ion exchange of benzimidazolium salt as a redox mediator
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The new benzimidazolium derivative (SM-1) salt with ion exchange from the (SM-0) was fabricated and characterized by protonnuclear magnetic resonance (1H-NMR), carbon-nuclear magnetic resonance (13C-NMR), Fourier-Transform infrared spectroscopy (FTIR), electrospray ionization (EIS-MS), thermal analysis (TG), cyclic voltammetry (CV), and ultraviolet-visible spectroscopy (UV-vis), for electrolytes (liquid or dried) in the DSSC charge transportation mechanism. Also, the influence of ion exchange from chloride to iodine in the synthesized electrolytes, compared to other electrolytes (conventional or commercial), was investigated about DSSC performance efficiency. When using as a liquid electrolyte (SM-1), the power conversion efficiency (n) of the working DSSC device was recorded as 1.980% and it was observed that the performances of DSSCs increased up to 56% when comparing dried electrolyte for SM-1 without conventional redox material (I-/I3 -). In the future, different molecular modifications of this type of benzimidazole derivatives or mixtures with conventional redox couples may further improve the performance of DSSC devices.
- Alici, B?lent,Dayan, Serkan,Karatas, Mert Olgun,Ozpozan, Nilg?n Kalaycioglu
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p. 333 - 341
(2021/05/28)
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- Homology modelling, molecular dynamics simulation and docking evaluation of β-tubulin of Schistosoma mansoni
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Schistosomiasis is one of the neglected diseases causing considerable morbidity and mortality throughout the world. Microtubules with its main component, tubulin play a vital role in helminthes including schistosomes. Benzimidazoles represent potential drug candidates by binding β-tubulin. The study aimed to generate a homology model for the β-tubulin of S. mansoni using the crystal structure of O vis aries (Sheep) β-tubulin (PDB ID: 3N2G D) as a template, then different β-tubulin models were generated and two previously reported benzimidazole derivatives (NBTP-F and NBTP-OH) were docked to the generated models, the binding results indicated that both S. mansoni, S. haematobium were susceptible to the two NBTP derivatives. Additionally, three mutated versions of S. mansoni β-tubulin wild-type were generated and the mutation (F185Y) seems to slightly enhance the ligand binding. Dynamics simulation experiments showed S. haematobium β-tubulin is highly susceptible to the tested compounds; similar to S. mansoni, moreover, mutated models of S. mansoni β-tubulin altered its NBTPs susceptibility. Moreover, additional seven new benzimidazole derivatives were synthesized and tested by molecular docking on the generated model binding site of S. mansoni β-tubulin and were found to have good interaction inside the pocket.
- El-Shehabi, Fouad,Mansour, Basem,Bayoumi, Waleed A.,El Bialy, Serry A.,Elmorsy, Mohammad A.,Eisa, Hassan M.,Taman, Amira
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- Design, synthesis and anticancer profile of new 4-(1H-benzo[d]imidazol-1-yl)pyrimidin-2-amine-linked sulfonamide derivatives with V600EBRAF inhibitory effect
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A new series of 4-(1H-benzo[d]imidazol-1-yl)pyrimidin-2-amine linked sulfonamide derivatives 12a–n was designed and synthesized according to the structure of well-established V600EBRAF inhibitors. The terminal sulfonamide moiety was linked to the pyrimidine ring via either ethylamine or propylamine bridge. The designed series was tested at fixed concentration (1 μM) against V600EBRAF, finding that 12e, 12i and 12l exhibited the strongest inhibitory activity among all target compounds and 12l had the lowest IC50 of 0.49 μM. They were further screened on NCI 60 cancer cell lines to reveal that 12e showed the most significant growth inhibition against multiple cancer cell lines. Therefore, cell cycle analysis of 12e was conducted to investigate the effect on cell cycle progression. Finally, virtual docking studies was performed to gain insights for the plausible binding modes of vemurafenib, 12i, 12e and 12l.
- Abdel-Maksoud, Mohammed S.,Mohamed, Ahmed A. B.,Hassan, Rasha M.,Abdelgawad, Mohamed A.,Chilingaryan, Garri,Selim, Samy,Abdel-Bakky, Mohamed S.,Al-Sanea, Mohammad M.
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- Visible light initiated oxidative coupling of alcohols ando-phenylenediamines to synthesize benzimidazoles over MIL-101(Fe) promoted by plasmonic Au
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The use of visible light to initiate one-pot synergistic/cascade reactions is a green and energy saving strategy. In this manuscript, we report that MIL-101(Fe) can act as a multifunctional catalyst to realize the oxidative condensation betweeno-phenylenediamines and alcohols to synthesize benzimidazoles under visible light. The deposition of plasmonic Au nanoparticles (Au NPs) on MIL-101(Fe) led to significantly improved activity. Both controlled experiments and electron spin resonance (ESR) results revealed that the production of benzimidazoles fromo-phenylenediamines and alcohols involves three sequential steps,i.e., the oxidative dehydrogenation of alcohols to produce aldehydes, the condensation betweeno-phenylenediamines and the aldehydes to produce Schiff bases and their oxidation to form benzimidazoles,viaa superoxide radical (O2˙?)-mediated pathway. The promoting effect of plasmonic Au NPs in this reaction can be ascribed to the effective transfer of the surface plasmon resonance (SPR)-excited hot electrons to the lowest unoccupied molecular orbital (LUMO) of MIL-101(Fe), which led to the generation of more active O2˙?radicals. This study not only provides a green and sustainable way for the synthesis of benzimidazoles, but also highlights the great potential of using rationally designed plasmonic metal NP/MOF nanocomposites as multifunctional catalysts for light initiated one-pot tandem/cascade reactions.
- Hao, Mingming,Li, Zhaohui,Qin, Yuhuan,Xu, Chao
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p. 4161 - 4169
(2021/06/17)
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- Highly efficient one pot synthesis of benzimidazoles from 2-nitroaniline and PhSiH3 as reducing agent catalyzed by Pd/C as a heterogeneous catalyst
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This work reports an efficient route for the synthesis of benzimidazole from o-nitroaniline in the presence of carbon dioxide atmosphere, PhSiH3 as a reducing agent catalyzed by Pd/C as a catalyst. Benzimidazoles have become the focus of organic chemists, as benzimidazole is an important intermediate in medicinal chemistry. We have developed more efficient route for the synthesis benzimidazole and various substituted benzimidazoles have been synthesized in good to excellent yield. The TBD (1,5,7-Triazabicyclo [4.4.0] dec-5-ene) is selected as a base as it promotes the CO2 insertion. Benzimidazoles were synthesized through reduction of nitro group followed by cyclization of amine using CO2 as a carbon source. Moreover, the Pd/C catalyst can be recycled up to five recycle run without significant changes in the yield of the product.
- Phatake, Vishal V.,Bhanage, Bhalchandra M.
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- A facile and versatile electro-reductive system for hydrodefunctionalization under ambient conditions
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A general electrochemical system for reductive hydrodefunctionalization is described, employing the inexpensive and easily available triethylamine (Et3N) as a sacrificial reductant. This protocol is characterized by facile operation, sustainable conditions, and exceptionally wide substrate scope covering the cleavage of C-halogen, N-S, N-C, O-S, O-C, C-C and C-N bonds. Notably, the selectivity and capability of reduction can be conveniently switched by simple incorporation or removal of an alcohol as a co-solvent.
- Huang, Binbin,Guo, Lin,Xia, Wujiong
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supporting information
p. 2095 - 2103
(2021/03/26)
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- Radical Chain Reduction via Carbon Dioxide Radical Anion (CO2?-)
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We developed an effective method for reductive radical formation that utilizes the radical anion of carbon dioxide (CO2?-) as a powerful single electron reductant. Through a polarity matched hydrogen atom transfer (HAT) between an electrophilic radical and a formate salt, CO2?- formation occurs as a key element in a new radical chain reaction. Here, radical chain initiation can be performed through photochemical or thermal means, and we illustrate the ability of this approach to accomplish reductive activation of a range of substrate classes. Specifically, we employed this strategy in the intermolecular hydroarylation of unactivated alkenes with (hetero)aryl chlorides/bromides, radical deamination of arylammonium salts, aliphatic ketyl radical formation, and sulfonamide cleavage. We show that the reactivity of CO2?- with electron-poor olefins results in either single electron reduction or alkene hydrocarboxylation, where substrate reduction potentials can be utilized to predict reaction outcome.
- Hendy, Cecilia M.,Jui, Nathan T.,Lian, Tianquan,Smith, Gavin C.,Xu, Zihao
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supporting information
p. 8987 - 8992
(2021/07/01)
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- Sustainable Synthesis of 2-Hydroxymethylbenzimidazoles using D-Fructose as a C2 Synthon
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D-fructose, a biomass-derived carbohydrate has been identified as an environmentally benign C2 synthon in the preparation of synthetically useful 2-hydroxymethylbenzimidazole derivatives by coupling with 1,2-phenylenediamines. Proof of concept was established by synthesizing 23 examples using BF3.OEt2 (20 mol%), TBHP (5.5 M, decane) (1.0 equiv.) in CH3CN at 90 °C for 1 h. The pivotal features of this method include metal-free conditions, short time, good functional group tolerance, gram scale feasibility and the synthesis of benzimidazole fused 1,4-oxazine. Control studies with conventional C2 synthons did not produce the desired product, thus suggesting a new reaction pathway from D-fructose.
- Raja, Dineshkumar,Philips, Abigail,Sundaramurthy, Devikala,Chandru Senadi, Gopal
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supporting information
p. 3754 - 3759
(2021/10/14)
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- A substituent- And temperature-controllable NHC-derived zwitterionic catalyst enables CO2upgrading for high-efficiency construction of formamides and benzimidazoles
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Chemocatalytic upgrading of the greenhouse gas CO2 to valuable chemicals and biofuels has attracted broad attention in recent years. Among the reported approaches, N-formylation of CO2 with an amine is of great significance due to its versatility in the construction of N-containing linear and cyclic skeletons. Herein, a stable N-heterocyclic carbene-carboxyl adduct (NHC-CO2) was facilely prepared and could be used as a recyclable zwitterionic catalyst for efficient CO2 reductive upgrading via either N-formylation or further coupling with cyclization under mild conditions (25 °C, 1 atm CO2) using hydrosilane as a hydrogen source. More than 30 different alkyl and aromatic amines could be transformed into the corresponding formamides or benzimidazoles with remarkable yields (74%-98%). The electronic effect of the introduced substituent on NHC-CO2 was found to evidently affect the thermostability and nucleophilicity of the zwitterionic catalyst, which is directly correlated with its catalytic activity. Moreover, NHC-CO2 could supply CO2 by in situ decarboxylation at a specific temperature that is dependent on the introduced substituent type. Experimental and computational studies showed that the carboxyl species on NHC-CO2 was not only a nucleophilic center, but also a C1 source which rapidly captures or substitutes ambient CO2 during hydrosilylation. In addition, a simple and green conceptual process was designed for the product purification and catalyst recycling, with a good feasibility for small-scale production.
- Li, Hu,Li, Zhengyi,Wu, Hongguo,Yang, Song,Yu, Zhaozhuo,Zhang, Lilong,Zhu, Kaixun
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supporting information
p. 5759 - 5765
(2021/08/23)
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- CO2 improved synthesis of benzimidazole with the catalysis of a new calcium 4-amino-3-hydroxybenzoate
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In this paper, we explored the synthesis of benzimidazole by the reaction of DMF and o-phenylenediamine. In the process of catalyst screening, we found that 4-amino-3-hydroxybenzoic acid, benzoic acid, and benzene-1,3,5-tricarboxylic acid could catalyze the reaction. Moreover, the calcium 4-amino-3-hydroxybenzoate and CO2 could more effectively catalyze the reaction, the synergistic effect of CO2 and 4-amino-3-hydroxybenzoic acid calcium salt can increase the yield of benzimidazole from 28% to 94%.
- Gao, Ruo-Xuan,Gao, Yuan-Yuan,Han, Li-Min,Zhu, Ning
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p. 205 - 211
(2021/06/07)
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- Reductive cyclization of o-phenylenediamine with CO2 and BH3NH3 to synthesize 1H-benzoimidazole derivatives
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A simple and green protocol was developed for the reductive cyclization of o-phenylenediamine with CO2 and BH3NH3 to yield 1H-benzimidazole. The desired 1H-benzimidazole derivatives were produced under mild conditions. Mechanism investigation indicated that the coordination of o-phenylenediamine with the boron atom of BH3NH3 promoted the transfer of the formyl group to form a stable intermediate, which facilitated the intramolecular nucleophilic addition-elimination for the formation of target product. In this process, BH3NH3 served multifunctional roles, acting as a reducing agent and a formylation catalyst.
- Han, Limin,Hong, Hailong,Li, Xiao,Yang, Yue,Zhang, Junhua,Zhu, Ning
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supporting information
(2021/09/28)
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- Method for synthesizing benzimidazole from carbon dioxide and o-phenylenediamine compound
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The invention discloses a method for synthesizing benzimidazole from carbon dioxide and an o-phenylenediamine compound, the method is characterized in that an amino-containing functionalized ordered mesoporous polymer is used as a catalyst, o-phenylenediamine and carbon dioxide are used as raw materials, dimethylaminoborane is used as a hydrogen reduction reagent, carbon dioxide and the o-phenylenediamine compound are catalyzed to react in an NMP solvent to generate a benzimidazole compound, wherein the dosage of a catalyst is 0.01-1mol% based on the nitrogen content of the o-phenylenediamine compound; the filling pressure of the carbon dioxide is 0.1-2MPa; the reaction temperature is 60-180DEG C; the molar ratio of the catalyst to the NMP is 1:50-100. Compared with the prior art, the catalyst has the advantages of simple preparation, high catalytic activity, capability of catalyzing the reaction of carbon dioxide and the o-phenylenediamine compound under mild conditions to generate benzimidazole and derivatives thereof, and the like.
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Paragraph 0016; 0023-0024
(2021/06/06)
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- Catalyst freeN-formylation of aromatic and aliphatic amines exploiting reductive formylation of CO2using NaBH4
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Herein, we report a sustainable approach forN-formylation of aromatic as well as aliphatic amines using sodium borohydride and carbon dioxide gas. The developed approach is catalyst free, and does not need pressure or a specialized reaction assembly. The reductive formylation of CO2with sodium borohydride generates formoxy borohydride speciesin situ, as confirmed by1H and11B NMR spectroscopy. Thein situformation of formoxy borohydride species is prominent in formamide based solvents and is critical for the success of theN-formylation reactions. The formoxy borohydride is also found to promote transamidation reactions as a competitive pathway along with reductive functionalization of CO2with amine leading toN-formylation of amines.
- Kumar, Arun,Kumar, Yashwant,Mahajan, Dinesh,Sharma, Nidhi,Sharma, Pankaj
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p. 25777 - 25787
(2021/08/05)
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- Application of sulfonic acid fabricated cobalt ferrite nanoparticles as effective magnetic nanocatalyst for green and facile synthesis of benzimidazoles
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This work represents the design and synthesis of efficient sulfonated cobalt ferrite solid acid catalyst. The synthesized solid acid green catalyst was characterized using various techniques viz. FT-IR, powder XRD, SEM, TEM and VSM. The obtained catalyst was used to synthesize biologically significant 2-substituted benzimidazole derivatives by condensation between o-phenylenediamine with various aromatic, aliphatic and heterocyclic aldehydes. High yield (up to 98 %), short reaction time (10?25 min), mild reaction condition, wide functional group tolerance, easy work-up procedure and excellent values of green chemistry metrices such as lower E factor (0.126), high RME value (88.83 %), carbon efficiency (100 %) and high atom economy (AE) value (90.65 %), are some salient features of the present catalytic system. Moreover, the catalyst recovery by simply using an external magnet and catalyst reusability up to 7 times without any significant loss in catalytic efficiency are some additional remarkable features of the current protocol.
- Yadav, Priyanka,Kakati, Praachi,Singh, Preeti,Awasthi, Satish K.
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- Acid-catalyzed chemodivergent reactions of 2,2-dimethoxyacetaldehyde and anilines
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Chemodivergent reactions of 2,2-dimethoxyacetaldehyde and anilines were described, which were established on the basis of either a C[sbnd]C bond cleavage or a rearrangement process of a reaction intermediate. These reactions proceeded in a condition-determined manner with good functional group tolerance. In the first model, 2,2-dimethoxyacetaldehyde reacted with aniline to form a new C[sbnd]N bond, in the presence of O2, via a C[sbnd]C bond cleavage reaction. However, in the second model, by performing the reaction in the absence of O2, Heyns rearrangement occurred and generated a new C[sbnd]O bond to form methyl phenylglycinate. Such condition-determined reactions not only offered the new way for value-added conversion of biomass-derived platform molecule, 2, 2-dimethoxyacetaldehyde, but also provided efficient methods for the synthesis of N-arylformamides and methyl phenylglycinates.
- Guo, Luxia,Chen, Zihao,Zhu, Hongmei,Li, Minghao,Gu, Yanlong
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supporting information
p. 1419 - 1422
(2020/11/12)
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- Rational Design, Synthesis and Evaluation of Novel C6-Bicycloalkaneimidazole Containing Imidazo[1,2-b]pyridazines for ASK1 Inhibition
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Apoptosis signal-regulating kinase 1 (ASK1) is a member of mitogen-activated protein kinase kinase kinase (MAP3K) family that involves downstream phosphorylation of MAP kinases, c-Jun N-terminal kinases, and p38 MAP kinases. ASK1 inhibitors could possibly be beneficial for ameliorating the development and progression of diseases. Especially, ASK1 has been of interest as one of therapeutic targets for nonalcoholic fatty liver disease as the most common chronic liver diseases including simple steatosis and nonalcoholic steatohepatitis. In this manuscript, novel ASK1 inhibitor lead KTA-29 which has an imidazo[1,2-b]pyridazine core with novel C6-bicycloheptaneimidazole is disclosed. With the novel imidazo[1,2-b]pyridazine core, structure-activity-relationship study for ASK1 potency is described and KTA-29 affinity toward ASK1 with molecular modeling study is explained.
- Lee, Yujin,Jang, Jiyoon,Bibi, Maimoona,Duggirala, Krishna Babu,Ji, Sang Hee,Lee, Ji Hun,Ahn, Sunjoo,Song, Jin Sook,Chae, Chong Hak,Kim, Seong Hwan,Lee, Kwangho
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p. 872 - 877
(2021/05/10)
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- Highly Efficient and Catalyst-Free Synthesis of Benzimidazoles in Aqueous Media
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Abstract: A convenient and highly efficient, catalysts-free synthesis of benzimidazoles in an aqueous medium has been developed. The conditions of the synthesis were optimized, and its scope was successfully extended to various substrates with good to excellent yields. The experimental procedure is simple, and the products can be isolated by filtration followed by recrystallization from water.
- Huang, W.-H.,Jin, Y.-J.,Ma, L.-F.,Wu, Y.,Zhou, L.-H.
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p. 825 - 830
(2021/06/12)
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- A Chemoselective and Desulfurative Chan–Lam Coupling: C–N Bond Formation between Benzimidazoline-2-Thiones and Arylboronic Acids
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An efficient method for the chemoselective and desulfurative Chan–Lam cross-coupling based on benzimidazoline-2-thiones was developed. By modulating the amount of the catalyst Cu(OAc)2·H2O, alkali, temperature, and solvent, the desulfurizational C–N bond formation product (N-arylbenzimidazoles) could be selectively furnished smoothly. The features of this protocol are an inexpensive and readily available catalyst, ligand-free conditions, wide substrate scope, easy performance, and moderate to excellent yields. It shows potential synthetic value for the preparation of a diversity of arylbenzoheterocyclic compounds, which are potentially active in pharmaceuticals and agrochemicals.
- Chen, Jin-Quan,Liu, Xing,Guo, Jia,Dong, Zhi-Bing
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p. 2414 - 2424
(2020/03/23)
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- METHOD OF CARBON MONOXIDE FIXATION AND METHOD OF AMINE FORMYLATION
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The present invention relates to a method for fixing carbon monoxide in a metal-free condition and a method for formating amine using the same.
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Paragraph 0078; 0081-0085; 0100-0102
(2021/02/19)
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- Selective CO2 adsorption and Lewis acid catalytic activity towards naphthimidazole synthesis by a Zn-MOF
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A two-fold interpenetrated, three dimensional Zn-based porous MOF, {[Zn(BPBA)Cl]?5H2O}n (1) [BPBA = 3,5-bis-(4-oxo-4H-pyridin-1-yl)-benzoate], has been synthesized at high temperature under solvothermal conditions by the in situ acidic hydrolysis of the tripodal ligand 3,5-bis-(4-oxo-4H-pyridin-1-yl)-benzonitrile (BPBN). The de-solvated MOF exhibited selective CO2 adsorption at a temperature of 195 K and 1 bar pressure over N2 and H2. Interestingly, the four coordinated Zn(II) sites in the MOF exhibited high Lewis acidic heterogeneous catalytic activity for the synthesis of naphthimidazole in excellent yield without pre-activation of the MOF. The Zn(II) sites could directly coordinate to the substrate to catalyze the chemical transformation by an expansion of the coordination number. The π-π supramolecular interactions between the aromatic rings of the framework and the substrate molecule might help in the substrate activation.
- Agarwal, Rashmi A.,De, Dinesh
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- Accelerated microdroplet synthesis of benzimidazoles by nucleophilic addition to protonated carboxylic acids
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We report a metal-free novel route for the accelerated synthesis of benzimidazole and its derivatives in the ambient atmosphere. The synthetic procedure involves 1,2-aromatic diamines and alkyl or aryl carboxylic acids reacting in electrostatically charged microdroplets generated using a nano-electrospray (nESI) ion source. The reactions are accelerated by orders of magnitude in comparison to the bulk. No other acid, base or catalyst is used. Online analysis of the microdroplet accelerated reaction products is performed by mass spectrometry. We provide evidence for an acid catalyzed reaction mechanism based on identification of the intermediate arylamides. Their dehydration to give benzimidazoles occurs in a subsequent thermally enhanced step. It is suggested that the extraordinary acidity at the droplet surface allows the carboxylic acid to function as a C-centered electrophile. Comparisons of this methodology with data from thin film and bulk synthesis lead to the proposal of three key steps in the reaction: (i) formation of an unusual reagent (protonated carboxylic acid) because of the extraordinary conditions at the droplet interface, (ii) accelerated bimolecular reaction because of limited solvation at the interface and (iii) thermally assisted elimination of water. Eleven examples are shown as evidence of the scope of this chemistry. The accelerated synthesis has been scaled-up to establish the substituent-dependence and to isolate products for NMR characterization.
- Basuri, Pallab,Gonzalez, L. Edwin,Morato, Nicolás M.,Pradeep, Thalappil,Cooks, R. Graham
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p. 12686 - 12694
(2020/12/29)
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- Effective and selective direct aminoformylation of nitroarenes utilizing palladium nanoparticles assisted by fibrous-structured silica nanospheres
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Abstract: Palladium nanoparticles (~ 1–3?nm, 0.4?wtpercent Pd) were uniformly distributed over the surface of fibrous silica nanospheres (KCC-1) modified via aminopropyltriethoxysilane using a fast and cost-effective palladium (II) chloride reduction process. The Pd nanoparticles (Pd NPs) distribution over the ensuing catalyst Pd/KCC-1-NH2 showed much more uniform distribution, and smaller size compared with the tedious hydrothermal reduction method. The morphological, chemical, and size analyses of Pd/KCC-1-NH2 by BET, UV–Vis spectra, XRD, HR-TEM, EDS and XPS analysis revealed that the succeeding material consist of a distinct fibrous silica nanospheres support adorn with Pd NPs. The resultant nanocatalyst was tested for the one-step reductive aminoformylation of aromatic nitro compounds using formic acid. A wide range of substituted nitroarenes including electron withdrawing, releasing, sterically hindered and multifunctional groups have been converted to corresponding aryl formamide in quantitative yields (yields up to 98percent) at moderate temperature (70?°C). Optimization study has proved that the 6 equivalent of formic acid is required and toluene was found to be the better solvent. The established practice is beneficial due to the use of formic acid as H2 source and formylating agent, easiness in handling of the catalyst and simple workup procedure with efficient catalyst reusability. Graphic abstract: [Figure not available: see fulltext.].
- Jaseer, E. A.,Qureshi, Ziyauddin S.
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- Flavin Nitroalkane Oxidase Mimics Compatibility with NOx/TEMPO Catalysis: Aerobic Oxidization of Alcohols, Diols, and Ethers
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Biomimetic flavin organocatalysts oxidize nitromethane to formaldehyde and NOx - providing a relatively nontoxic, noncaustic, and inexpensive source for catalytic NO2 for aerobic TEMPO oxidations of alcohols, diols, and ethers. Alcohols were oxidized to aldehydes or ketones, cyclic ethers to esters, and terminal diols to lactones. In situ trapping of NOx and formaldehyde suggest an oxidative Nef process reminiscent of flavoprotein nitroalkane oxidase reactivity, which is achieved by relatively stable 1,10-bridged flavins. The metal-free flavin/NOx/TEMPO catalytic cycles are uniquely compatible, especially compared to other Nef and NOx-generating processes, and reveal selectivity over flavin-catalyzed sulfoxide formation. Aliphatic ethers were oxidized by this method, as demonstrated by the conversion of (-)-ambroxide to (+)-sclareolide.
- Thapa, Pawan,Hazoor, Shan,Chouhan, Bikash,Vuong, Thanh Thuy,Foss, Frank W.
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p. 9096 - 9105
(2020/08/14)
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- A NaH-promoted N-detosylation reaction of diverse p-toluenesulfonamides
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A NaH-mediated detosylation reaction of various Ts-protected indoles, azaheterocycles, anilines and dibenzylamine was reported. The method features cheap reagent, convenient operations, mild reaction conditions and broad substrate scope. Moreover, this study revealed that the loading of NaH in tosylation reactions of nitrogen-containing compounds with NaH as a base in DMA or DMF should be controlled due to the possibility of adverse detosylation.
- Sun, Wanwan,Chen, Xiaobei,Hu, Ying,Geng, Huihui,Jiang, Yuanrui,Zhou, Yuxin,Zhu, Wenjing,Hu, Min,Hu, Haohua,Wang, Xingyi,Wang, Xinli,Zhang, Shilei,Hu, Yanwei
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supporting information
(2020/10/05)
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- Electron Transfer Photoredox Catalysis: Development of a Photoactivated Reductive Desulfonylation of an Aza-Heteroaromatic Ring
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Herein, we report a protocol for desulfonylation of aza-heteroaromatic rings via photoinduced electron transfer and hydrogen atom transfer. This general protocol has a wide substrate range and moderate to good yields. The utility of the method was demonstrated by the chemoselective desulfonylation of a molecule containing both an aliphatic and an aromatic sulfonamide. (Figure presented.).
- Qiang-Liu,Liu, Yu-Xiu,Song, Hong-Jian,Wang, Qing-Min
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supporting information
p. 3110 - 3115
(2020/07/04)
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- Discovery and characterization of an acridine radical photoreductant
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Photoinduced electron transfer (PET) is a phenomenon whereby the absorption of light by a chemical species provides an energetic driving force for an electron-transfer reaction1–4. This mechanism is relevant in many areas of chemistry, including the study of natural and artificial photosynthesis, photovoltaics and photosensitive materials. In recent years, research in the area of photoredox catalysis has enabled the use of PET for the catalytic generation of both neutral and charged organic free-radical species. These technologies have enabled previously inaccessible chemical transformations and have been widely used in both academic and industrial settings. Such reactions are often catalysed by visible-light-absorbing organic molecules or transition-metal complexes of ruthenium, iridium, chromium or copper5,6. Although various closed-shell organic molecules have been shown to behave as competent electron-transfer catalysts in photoredox reactions, there are only limited reports of PET reactions involving neutral organic radicals as excited-state donors or acceptors. This is unsurprising because the lifetimes of doublet excited states of neutral organic radicals are typically several orders of magnitude shorter than the singlet lifetimes of known transition-metal photoredox catalysts7–11. Here we document the discovery, characterization and reactivity of a neutral acridine radical with a maximum excited-state oxidation potential of ?3.36 volts versus a saturated calomel electrode, which is similarly reducing to elemental lithium, making this radical one of the most potent chemical reductants reported12. Spectroscopic, computational and chemical studies indicate that the formation of a twisted intramolecular charge-transfer species enables the population of higher-energy doublet excited states, leading to the observed potent photoreducing behaviour. We demonstrate that this catalytically generated PET catalyst facilitates several chemical reactions that typically require alkali metal reductants and can be used in other organic transformations that require dissolving metal reductants.
- MacKenzie, Ian A.,Wang, Leifeng,Onuska, Nicholas P. R.,Williams, Olivia F.,Begam, Khadiza,Moran, Andrew M.,Dunietz, Barry D.,Nicewicz, David A.
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- Nickel-Catalyzed Dehydrogenation of N-Heterocycles Using Molecular Oxygen
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Herein, an efficient and selective nickel-catalyzed dehydrogenation of five- and six-membered N-heterocycles is presented. The transformation occurs in the presence of alkyl, alkoxy, chloro, free hydroxyl and primary amine, internal and terminal olefin, trifluoromethyl, and ester functional groups. Synthesis of an important ligand and the antimalarial drug quinine is demonstrated. Mechanistic studies revealed that the cyclic imine serves as the key intermediate for this stepwise transformation.
- Banerjee, Debasis,Bera, Atanu,Bera, Sourajit
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supporting information
(2020/09/02)
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- UiO-66 as an efficient catalyst for N-formylation of amines with CO2 and dimethylamine borane as a reducing agent
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The most effective way to make the best use of CO2, is the reductive formylation of amines, as formamides have many applications in industry. A new protocol has been developed for reductive N-formylation of amines with CO2 as a C1 carbon source and DMAB (Dimethylamine borane) as a reducing agent in the presence of Zr-containing metal–organic framework (MOF) as an efficient, heterogeneous recyclable catalyst. We used UiO-66 and UiO-66-NH2 as catalysts for N-formylation of amines and observed that both the catalyst performs equally. Therefore, we continued our studies with UiO-66 as a catalyst. The UiO-66 MOF shows good catalytic activity and affording the desired formamides in good to excellent yield. This catalytic system is very efficient for several amines including primary and secondary aliphatic cyclic and aromatic amines. Moreover, the prepared catalyst was recycled up to four recycled without a considerable decrease in catalytic activity.
- Phatake, Vishal V.,Mishra, Ashish A.,Bhanage, Bhalchandra M.
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supporting information
(2019/12/11)
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- Tetracoordinate borates as catalysts for reductive formylation of amines with carbon dioxide
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We report sodium trihydroxyaryl borates as the first robust tetracoordinate organoboron catalysts for reductive functionalization of CO2. These catalysts, easily synthesized from condensing boronic acids with metal hydroxides, activate main group element-hydrogen (E-H) bonds efficiently. In contrast to BX3 type boranes, boronic acids and metal-BAr4 salts, under transition metal-free conditions, sodium trihydroxyaryl borates exhibit high reactivity of reductive N-formylation toward a variety of amines (106 examples), including those with functional groups such as ester, olefin, hydroxyl, cyano, nitro, halogen, MeS-, ether groups, etc. The over-performance to catalyze formylation of challenging pyridyl amines affords a promising alternative method to the use of traditional formylation reagents. Mechanistic investigation supports electrostatic interactions as the key for Si/B-H activation, enabling alkali metal borates as versatile catalysts for hydroborylation, hydrosilylation, and reductive formylation/methylation of CO2.
- Du, Chen-Xia,Huang, Zijun,Jiang, Xiaolin,Li, Yuehui,Makha, Mohamed,Wang, Fang,Zhao, Dongmei
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supporting information
p. 5317 - 5324
(2020/09/17)
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- Reevaluating the synthesis of 2,5-disubstituted-1H-benzimidazole derivatives by different green activation techniques and their biological activity as antifungal and antimicrobial inhibitor
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A comparative study concerned with the preparation of diversely substituted-1H-benzimidazole under different green activation techniques and conventional methods is reported. Data are collected for infrared, ultrasound, microwave, and simultaneous irradiation with US and IR sources, as this last strategy shows an important improvement. Further, the small library of potentially bioactive benzimidazole 17-76 synthesized was screened as an antifungal and antimicrobial agent. Strong activity against Candida albicans and Staphylococcus aureus was observed. Remarkably, 2-(4-aminophenyl)-5-phenylamino-1H-benzimidazole 63 resulted better than that of reference drugs miconazole with a zone of inhibition up to 42 mm. Likewise, 2-(2-aminophenyl)-1H-benzimidazole 21 showed substantial antimicrobial activity against MRSA strain. When assayed by the microdilution method, this azaheterocyclic compound presented a minimum inhibitory concentration (MIC) ≥ 16.4 μg/100 mL and a bacterial percentage reduction of 96%.
- Penieres-Carrillo, José-Guillermo,Ríos-Guerra, Hulme,Pérez-Flores, Javier,Rodríguez-Molina, Braulio,Torres-Reyes, ángeles,Barrera-Téllez, Francisco,González-Carrillo, Jessica,Moreno-González, Lessly,Martínez-Zaldívar, Alejandro,Nolasco-Fidencio, Juan-Jesús,Matus-Meza, Audifás-Salvador,Luna-Mora, Ricardo-Alfredo
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supporting information
p. 436 - 455
(2019/12/27)
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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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- Nano indium oxide-catalyzed domino reaction for the synthesis of N-alkoxylated benzimidazoles
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A convenient method has been developed for the selective synthesis of N-alkoxylated benzimidazole derivatives by the cyclocondensation reaction of simple ortho-phenylenediamine, formaldehyde and alcohols in presence of indium oxide nanoparticles as catalyst. The alcohol acts as reactant as well as solvent in this reaction. No other solvents or additives have been used for this reaction. The catalyst can be reused several times without significant loss of catalytic activity. A probable reaction mechanism has been proposed based on some control experiments.
- Samanta, Satyajit,Mahato, Sachinta,Chatterjee, Rana,Santra, Sougata,Zyryanov, Grigory V.,Majee, Adinath
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- Endogenous X-C=O species enable catalyst-free formylation prerequisite for CO2reductive upgrading
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CO2, the main component of greenhouse gas, is currently developed as a promising surrogate of carbon feedstock. Among various conversion routes, CO2undergoing catalytic reduction can furnish hydrogen/energy carriers and value-added chemicals, while specific metal-containing catalysts or organocatalysts are often prerequisite for smooth proceeding of the involved reaction processes. In this work, both formic acid and N-containing benzoheterocyclic compounds (including various benzimidazoles, benzothiazole, and benzoxazole) along with silanols could be synthesized with high yields (>90%) from catalyst-free reductive upgrading of CO2under mild conditions (50 °C). The endogenous X-CO species, derived from the N-methyl-substituted amide-based solvent [Me2N-C(O)-R], especially PolarClean, and O-formyl group [O-C(O)-H] of in situ formed silyl formate, were found to play a prominent promotional role in the activation of the used hydrosilane for reductive CO2insertion, as demonstrated by density functional theory (DFT) calculations and isotopic labeling experiments. Moreover, reaction mechanisms and condition-based sensitivity assessment were also delineated.
- Dai, Wenshuai,Li, Hu,Saravanamurugan, Shunmugavel,Wu, Hongguo,Yang, Song
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p. 5822 - 5832
(2020/10/21)
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- Visible-light-induced aerobic oxidative desulfurization of 2-mercaptobenzimidazolesviaa sulfinyl radical
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A mild transition-metal-free non-toxic aerobic photoredox system was found to enable highly efficient desulfurization of 2-mercaptobenzimidazoles. This viable catalytic system includes Rose Bengal in a low catalyst loading as a photosensitizer and cheap, non-toxic NaCl in a catalytic amount as an additive, combined with an oxygen atmosphere. This protocol provides an important alternative access to a broad range of benzimidazole and deuterated benzimidazole products in generally high yields with good tolerance of various synthetically and pharmaceutically useful functionalities. The mechanistic studies reveal that both single electron transfer and energy transfer probably occur in the initial step and a sulfinyl radical intermediate is involved in the key desulfurization process.
- Deng, Guo-Jun,Fu, Mei,Huang, Huawen,Ji, Xiaochen,Li, Yongtong
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supporting information
p. 5594 - 5598
(2020/09/21)
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- Identification of intermediate compounds and photodegradation mechanisms of omeprazole under the system UV/O2
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The photodegradation of the proton pump inhibitor omeprazole (OME) in aqueous media with the system UV/O2 is presented. The photodegradation rate was assessed by HPLC and UV-vis spectroscopy, while the mineralization rate was obtained by TOC measurements. Degradation products were investigated by IR spectroscopy and GC-MS analysis. UV-vis absorbance and HPLC results indicated that OME is completely degraded within 3?minutes of irradiation. TOC analysis indicated that intermediates compounds are relatively easy to mineralize since 80% mineralization is achieved within 2?hours. IR studies demonstrated a rapid oxidation of OME leading to the formation of amines and both sulfonic and carboxylic acids. GC-MS data indicated that the initial photoproducts are derivatives of both benzimidazole and pyridine produced after the photochemical cleavage of the C–S bond. Plausible mechanisms for the direct and indirect degradation of OME are given. In the photochemical degradation of OME, many intermediate compounds are actually generated. Several of them were generated from hydroxyl radical reactions, but some of them resulted from rearrangements, reductive reactions, and through the formation of highly reactive intermediates such as pseudo carbene, thiooxirane, and sulfenamide.
- Leyva, Elisa,Moctezuma, Edgar,Baines, Kim M.,Noriega, Saúl,Pérez Flores, Francisco,Lara-Pérez, Carmen
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- K2S as Sulfur Source and DMSO as Carbon Source for the Synthesis of 2-Unsubstituted Benzothiazoles
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We describe a three-component reaction of o-iodoanilines with K2S and DMSO that provides 2-unsubstituted benzothiazoles in moderate to good isolated yields with good functional group tolerance. Electron-rich aromatic amines and o-phenylenediamines instead of o-iodoanilines provided 2-unsubstituted benzothiazoles and 2-unsubstituted benzimidazoles with and without K2S under similar conditions. Notably, DMSO plays three vital roles: carbon source, solvent, and oxidant.
- Deng, Guobo,Kuang, Daizhi,Liang, Yun,Yang, Yuan,Yu, Jiangxi,Zhang, Fuxing,Zhu, Xiaoming
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supporting information
p. 3789 - 3793
(2020/06/04)
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- Synthesis method of ammonium acetate mediated benzimidazole compound
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The invention discloses a synthesis method of a benzimidazole compound mediated by ammonium acetate. The synthesis method comprises the following steps: adding an o-phenylenediamine compound, dimethylsulfoxide, an additive 1 and an additive 2 into a reaction tube, carrying out a stirring reaction at 130-150 DEG C, cooling the reaction product to room temperature after the reaction is finished, and carrying out separation and purification on the product to obtain the benzimidazole compound. The invention develops a method for synthesizing a benzimidazole compound under the mediation of ammonium acetate by taking DMSO as a carbon source and an oxidant and an o-phenylenediamine compound as a substrate under the condition of no metal catalyst. The synthesis method does not need a metal catalyst, and the required carbon source and oxidant have the characteristics of low toxicity, low price, easiness in obtaining, stable performance and the like. The method has the advantages of easiness inoperation, few steps, mild reaction conditions, better functional group tolerance and the like, and provides a new valuable way for synthesizing benzimidazole compounds.
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Paragraph 0033-0035
(2020/11/23)
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- Visible-Light-Mediated N-Desulfonylation of N-Heterocycles Using a Heteroleptic Copper(I) Complex as a Photocatalyst
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A photoredox protocol that uses a heteroleptic Cu (I) complex, [Cu(dq)(BINAP)]BF4, has been developed for the photodeprotection of benzenesulfonyl-protected N-heterocycles. A range of substrates was examined, including indazoles, indoles, pyrazoles, and benzimidazole, featuring both electron-rich and electron-deficient substituents, giving good yields of the N-heterocycle products with broad functional group tolerance. This transformation was also found to be amenable to flow reaction conditions.
- Hunter, Cameron J.,Boyd, Michael J.,May, Gregory D.,Fimognari, Robert
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p. 8732 - 8739
(2020/07/16)
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- Synthesis, EGFR-TK inhibition and anticancer activity of new quinoxaline derivatives
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Ethyl 4-substituted-3-oxo-quinoxaline-2-carboxylates 3–5 were obtained via alkylation of ethyl 3-oxo-3,4-dihydroquinoxaline-2-carboxylate (1). Compound 1 was heterocyclized using hydrazines, ethylenediamine, and ethanolamine to give pyrazoloquinoxalines 6, 7, diazepinoquinoxaline 8, and oxazepinoquinoxaline 10. The quinoxaline-2-carboxamides 9, 11, 12 were prepared via condensation of compound 1 with different amines. Compound 1 was thiated using Lawesson’s reagent affording quinoxaline-3-thione 13, in fair yield. In addition, the reaction of 4-methyl-3-oxoquinoxaline 3 with some binucleophiles led to a series of new oxoquinoxaline derivatives 14–18. The molecular structure of compounds 1, 3, and 9 was confirmed by X-ray crystallography. The anti-proliferative activity showed that among all the tested compounds, compounds 3, (IC50 2.51 ± 3.0, 4.22 ± 1.6 and 2.27 ± 1.9 μM), 11 (IC50 1.32 ± 2.61, 1.41 ± 1.23 and 1.18 ± 1.91 μM) and 17 (IC50 1.72 ± 1.32, 1.85 ± 0.94 and 1.92 ± 4.83 μM) showed noteworthy anti-proliferative effects against the three cancer cell lines, HCT116, HePG2 and MCF7, respectively, compared to the reference drugs doxorubicin (IC50 1.41 ± 0.58, 0.90 ± 0.62 and 1.01 ± 3.02 μM) and erlotinib (IC50 1.63 ± 0.81, 1.57 ± 0.62 and 1.49 ± 0.54 μM). Compounds 3 (0.899 nM), 11 (0.508 nM) and 17 (0.807) showed strong EGFR inhibitory activity compared to Erlotinib (0.439 nM) and these results are in agreement with the docking study. These results suggest that compounds could probably be promising anticancer agents with EGFR inhibitory activity.
- Ahmed, Eman A.,Mohamed, Mamdouh F. A.,Omran, Ahmed,Salah, Hanan
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supporting information
p. 2924 - 2940
(2020/07/13)
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- Facile access to: N-formyl imide as an N-formylating agent for the direct synthesis of N-formamides, benzimidazoles and quinazolinones
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N-Formamide synthesis using N-formyl imide with primary and secondary amines with catalytic amounts of p-toluenesulfonic acid monohydrate (TsOH·H2O) is described. This reaction is performed in water without the use of surfactants. Moreover, N-formyl imide is efficiently synthesized using acylamidines with TsOH·H2O in water. In addition, N-formyl imide was successfully used as a carbonyl source in the synthesis of benzimidazole and quinazolinone derivatives. Notable features of N-formylation of amines by using N-formyl imide include operational simplicity, oxidant- A nd metal-free conditions, structurally diverse products, and easy applicability to gram-scale operation.
- Huang, Hsin-Yi,Liang, Chien-Fu,Lin, Xiu-Yi,Yen, Shih-Yao
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supporting information
p. 5726 - 5733
(2020/08/21)
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- Transition-metal and oxidant-free approach for the synthesis of diverse N-heterocycles by TMSCl activation of isocyanides
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A highly efficient TMSCl-mediated addition of N-nucleophiles to isocyanides has been achieved. This transition-metal and oxidant-free strategy has been applied to the construction of various N-heterocyles such as quinazolinone, benzimidazole and benzothiazole derivatives by the use of distinct amino-based binucleophiles. The notable feature of this protocol includes its mild reaction condition, broad functional group tolerance and excellent yield. This journal is
- Chen, Fen-Er,Dong, Lin,Li, Hongyan,Liu, Jinxin,Luo, Liangliang,Xiao, You-Cai,Zhou, Yuan
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p. 29257 - 29262
(2020/10/02)
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- Method for generating nitrogen-containing heterocyclic ring products by catalyzing lignin and amino-containing compound with acid
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The invention provides a method for generating nitrogen-containing heterocyclic ring products by catalyzing lignin and an amino-containing compound with acid, belonging to the technical field of lignin degradation. According to the invention, lignin and the amino-containing compound are catalyzed by acid to directly generate the nitrogen heterocyclic derivatives in one step, and excellent yield (60-100%) is obtained in degradation of lignin; meanwhile, the method disclosed by the invention has high atom utilization rate; and in traditional degradation of lignin to generate benzaldehyde or benzoic acid, beta-C and gamma-C mostly generate byproducts such as formaldehyde, formic acid or carbon dioxide and cannot be fully utilized, but however, beta-C and gamma-C in lignin can generate nitrogen-containing heterocyclic ring products of the same series together with amino-containing compound raw materials according to the method in the invention, and the method has great application value inthe aspect of medicine.
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Paragraph 0111-0121
(2020/08/06)
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- Metal-Free Synthesis of Benzimidazoles via Oxidative Cyclization of d -Glucose with o-Phenylenediamines in Water
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d-Glucose has been identified as an efficient C1 synthon in the synthesis of benzimidazoles from o-phenylenediamines via an oxidative cyclization strategy. Isotopic studies with 13C6-d-glucose and D2O unambiguously confirmed the source of methine. The notable features of this method include the following: broad functional group tolerance, a biorenewable methine source, excellent reaction yields, a short reaction time, water as an environmentally benign solvent, and the synthesis of vitamin B12 component on the gram scale.
- Raja, Dineshkumar,Philips, Abigail,Palani, Pushbaraj,Lin, Wei-Yu,Devikala, Sundaramurthy,Senadi, Gopal Chandru
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p. 11531 - 11540
(2020/10/12)
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- Silver-Catalyzed, N-Formylation of Amines Using Glycol Ethers
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A silver-catalyzed protocol was found to afford the N-formylation of amines in moderate-to-good yields. Ethylene glycol-derived, oligomeric ethers were found to function as the formylating agent, with 1,4-dioxane affording the best results. This reaction does not require the use of stoichiometric activating reagents, and avoids the use of explosive reagents or toxic gases, such as CO, as the C1 synthon. Mechanistic studies indicate a single-electron transfer-based pathway. This work highlights the ability of silver to participate in unexpected reaction pathways.
- King, Bradley H.,Wang, Michelle L.,Jesse, Kate A.,Kaur, Guneet,Tran, Brianna,Walser-Kuntz, Ryan,Iafe, Robert G.,Wenzel, Anna G.
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p. 13256 - 13263
(2020/11/26)
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