55899-43-9Relevant academic research and scientific papers
1,2-Disubstituted Benzimidazoles by the Iron Catalyzed Cross-Dehydrogenative Coupling of Isomeric o-Phenylenediamine Substrates
Foss, Frank W.,Palacios, Philip M.,Pierce, Brad S.,Thapa, Pawan,Tran, Tam
, p. 1991 - 2009 (2020/03/13)
Benzimidazoles are common in nature, medicines, and materials. Numerous strategies for preparing 2-arylbenzimidazoles exist. In this work, 1,2-disubstituted benzimidazoles were prepared from various mono- and disubstituted ortho-phenylenediamines (OPD) by iron-catalyzed oxidative coupling. Specifically, O2 and FeCl3·6H2O catalyzed the cross-dehydrogenative coupling and aromatization of diarylmethyl and dialkyl benzimidazole precursors. N,N′-Disubstituted-OPD substrates were significantly more reactive than their N,N-disubstituted isomers, which appears to be relative to their propensity for complexation and charge transfer with Fe3+. The reaction also converted N-monosubstituted OPD substrates to 2-substituted benzimidazoles; however, electron-poor substrates produce 1,2-disubstituted benzimidazoles by intermolecular imino-transfer. Kinetic, reagent, and spectroscopic (UV-vis and EPR) studies suggest a mechanism involving metal-substrate complexation, charge transfer, and aerobic turnover, involving high-valent Fe(IV) intermediates. Overall, comparative strategies for the relatively sustainable and efficient synthesis of 1,2-disubstituted benzimidazoles are demonstrated.
Synthesis of Structurally Diverse Benzotriazoles via Rapid Diazotization and Intramolecular Cyclization of 1,2-Aryldiamines
Faggyas, Réka J.,Sloan, Nikki L.,Buijs, Ned,Sutherland, Andrew
supporting information, p. 5344 - 5353 (2019/05/21)
An operationally simple method has been developed for the preparation of N-unsubstituted benzotriazoles by diazotization and intramolecular cyclization of a wide range of 1,2-aryldiamines under mild conditions, using a polymer-supported nitrite reagent and p-tosic acid. The functional group tolerance of this approach was further demonstrated with effective activation and cyclization of N-alkyl, -aryl, and -acyl ortho-aminoanilines leading to the synthesis of N1-substituted benzotriazoles. The synthetic utility of this one-pot heterocyclization process was exemplified with the preparation of a number of biologically and medicinally important benzotriazole scaffolds, including an α-amino acid analogue.
Novel purine benzimidazoles as antimicrobial agents by regulating ROS generation and targeting clinically resistant Staphylococcus aureus DNA groove
Wang, Ya-Nan,Bheemanaboina, Rammohan R. Yadav,Cai, Gui-Xin,Zhou, Cheng-He
supporting information, p. 1621 - 1628 (2018/03/29)
A novel series of purine benzimidazole hybrids were designed and synthesized for the first time with the aim to circumvent the increasing antibiotic resistance. Hexyl appended hybrid 3c gave potent activities against most of the tested bacteria and fungi especially against multidrug-resistant strains Staphylococcus aureus (MIC = 4 μg/mL). Structure-activity relationships revealed that the benzimidazole fragment at the 9-position of purine played an important role in exerting potentially antibacterial activity. Both cell toxicity and ROS generation assays indicated that the purine derivative 3c showed low cytotoxicity and could be used as a safe agent. Molecular modeling suggested that hybrid 3c could bind with the residues of Topo IA through hydrogen bonds and electrostatic interactions. Quantum chemical studies were also performed on the target compound 3c to understand the structural features essential for activity. The active molecule 3c could effectively interact with S. aureus DNA to form 3c–DNA complex through groove binding mode, which might block DNA replication to display their powerful antimicrobial activity.
Discovery of Benzimidazole–Quinolone Hybrids as New Cleaving Agents toward Drug-Resistant Pseudomonas aeruginosa DNA
Wang, Ya-Nan,Bheemanaboina, Rammohan R. Yadav,Gao, Wei-Wei,Kang, Jie,Cai, Gui-Xin,Zhou, Cheng-He
, p. 1004 - 1017 (2018/04/30)
A series of benzimidazole–quinolone hybrids as new potential antimicrobial agents were designed and synthesized. Bioactive assays indicated that some of the prepared compounds exhibited potent antibacterial and antifungal activities. Notably, 2-fluorobenzyl derivative 5 b (ethyl 7-chloro-6-fluoro-1-[[1-[(2-fluorophenyl)methyl]benzimidazol-2-yl]methyl]-4-oxo-quinoline-3-carboxylate) showed remarkable antimicrobial activity against resistant Pseudomonas aeruginosa and Candida tropicalis isolated from infected patients. Active molecule 5 b could not only rapidly kill the tested strains, but also exhibit low toxicity toward Hep-2 cells. It was more difficult to trigger the development of bacterial resistance of P. aeruginosa against 5 b than that against norfloxacin. Molecular docking demonstrated that 5 b could effectively bind with topoisomerase IV–DNA complexes, and quantum chemical studies theoretically elucidated the good antimicrobial activity of compound 5 b. Preliminary experimental reaction mechanism exploration suggested that derivative 5 b could not intercalate into DNA isolated from drug-resistant P. aeruginosa, but was able to cleave DNA effectively, which might further block DNA replication to exert powerful bioactivities. In addition, compound 5 b is a promising antibacterial agent with membrane disruption abilities.
Discovery of isoalloxazine derivatives as a new class of potential anti-Alzheimer agents and their synthesis
Kanhed, Ashish M.,Sinha, Anshuman,Machhi, Jatin,Tripathi, Ashutosh,Parikh, Zalak S.,Pillai, Prakash P.,Giridhar, Rajani,Yadav, Mange Ram
, p. 7 - 12 (2015/06/08)
This article describes discovery of a novel and new class of cholinesterase inhibitors as potential therapeutics for Alzheimer's disease. A series of novel isoalloxazine derivatives were synthesized and biologically evaluated for their potential inhibitory outcome for both acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE). These compounds exhibited high activity against both the enzymes AChE as well as BuChE. Of the synthesized compounds, the most potent isoalloxazine derivatives (7m and 7q) showed IC50 values of 4.72 μM and 5.22 μM respectively against AChE; and, 6.98 μM and 5.29 μM respectively against BuChE. These two compounds were further evaluated for their anti-aggregatory activity for β-amyloid (Aβ) in presence and absence of AChE by performing Thioflavin-T (ThT) assay and Congo red (CR) binding assay. In order to evaluate cytotoxic profile of these two potential compounds, cell viability assay of SH-SY5Y human neuroblastoma cells was performed. Further, to understand the binding behavior of these two compounds with AChE and BuChE enzymes, docking studies have been reported.
"All-water" one-pot diverse synthesis of 1,2-disubstituted benzimidazoles: Hydrogen bond driven 'synergistic electrophile-nucleophile dual activation' by water
Kommi, Damodara N.,Jadhavar, Pradeep S.,Kumar, Dinesh,Chakraborti, Asit K.
, p. 798 - 810 (2013/04/24)
A new "all-water" tandem arylaminoarylation/arylaminoalkylation- reduction-cyclisation route is reported for one-pot diversity oriented synthesis of regiodefined 1,2-disubstituted benzimidazoles. Water plays a crucial and indispensable role through hydrogen bond driven 'synergistic electrophile-nucleophile dual activation' in the formation of N-mono-aryl/aryl alkyl/alkyl/cycloalkyl o-nitroanilines under metal and base-free conditions to replace the transition metal-based C-N bond formation (aryl amination) chemistry and underlines the origin of regiodefined installation of the diverse selection of aryl, aryl alkyl, and alkyl/cycloalkyl groups as substituents on the benzimidazole scaffold to form the 1,2-disubstituted benzimidazoles. The influence of the hydrogen bond effect of water in promoting the arylaminoarylation reaction under base and metal-free conditions has been realized through observation of inferior yields in D2O compared to that obtained in water during the reaction of o-fluoronitrobenzene with aniline separately performed in water and D2O under similar experimental conditions. Water also provides assistance in promoting the subsequent nitro reduction and in the final cyclocondensation steps. The role of water in promoting the cyclocondensation reaction through hydrogen bonds is realized by the differential product yields during the reaction of mono-N-phenyl-o- phenylenediamine with benzaldehyde performed separately in water and D 2O. The better hydrogen bond donor and hydrogen bond acceptor abilities of water compared to those of the organic solvents are the contributing/deciding factors for making the new water-assisted tandem arylaminoarylation/arylaminoalkylation-reduction-cyclisation strategy for the diversified synthesis of the regiodefined 1,2-disubstituted benzimidazoles effective in an aqueous medium, making it represent a true "all-water chemistry."
A Pd(II)-catalyzed oxidative cyclization for the preparation of aryl-fused six-membered nitrogen heterocycles with 2-acetoxy functionality
Wang, Xiaolei,Wu, Zhengxing,Zhu, Xiaowen,Ye, Chenghao,Jiang, Feng,Zhang, Wanbin
, p. 132 - 138 (2013/08/24)
A Pd(II)-catalyzed oxidative cyclization of olefinic tosylamides was developed for the preparation of aryl-fused and N-containing six-membered heterocycles. Under optimized conditions the reaction proceeded with high activity and selectivity, with yields
A highly active catalyst supported molecular sieves-NaHCO3 mixture for the selective and advantageous N-monoalkylation of amines
Das, Asish R.,Medda, Arunima,Singha, Raghunath,Guchhait, Nikhil
experimental part, p. 841 - 848 (2010/06/01)
Amines are mono-N-alkylated by alkylmesylates in the presence of catalyst supported molecular sieves-NaHCO3 mixture in a regioselective, chemoselective and non-toxic process. Observed chemoselectivity is supported by 'DFT'.
An improved method of synthesis of precursors for amino-Claisen rearrangement
Jain, Seema,Pandey, Neelesh,Kishore
, p. 1052 - 1054 (2007/10/03)
N-Allylarylamines are useful precursors in amino-Claisen rearrangements affording 2-allylarylamines in one step. An improved method for the synthesis of a series of N-allylarylamines (2a-h) has been described.
Radical-induced formation of some siloles and diazasiloles
Ding, Bangwei,Teng, Zhu,Keese, Reinhart
, p. 8906 - 8910 (2007/10/03)
The Bu3Sn radical-induced reaction of o-iodobenzylvinylsilanes and o-iodoallylsilanes leads to cyclic products in yields of 40-60%. These regioselective cyclizations occur with high preference for a 5-exo and a 7-endo mode with a 6-exo mode being absent. An example for ring closure via a 7-exo mode is described.
