- 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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- Synthesis and evaluation of selected benzimidazole derivatives as potential antimicrobial agents
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A library of 53 benzimidazole derivatives, with substituents at positions 1, 2 and 5, were synthesized and screened against a series of reference strains of bacteria and fungi of medical relevance. The SAR analyses of the most promising results showed that the antimicrobial activity of the compounds depended on the substituents attached to the bicyclic heterocycle. In particular, some compounds displayed antibacterial activity against two methicillin-resistant Staphylococcus aureus (MRSA) strains with minimum inhibitory concentrations (MICs) comparable to the widely-used drug ciprofloxacin. The compounds have some common features; three possess 5-halo substituents; two are derivatives of (S)-2-ethanaminebenzimidazole; and the others are derivatives of one 2-(chloromethyl)-1Hbenzo[ d]imidazole and (1H-benzo[d]imidazol-2-yl)methanethiol. The results from the antifungal screening were also very interesting: 23 compounds exhibited potent fungicidal activity against the selected fungal strains. They displayed equivalent or greater potency in their MIC values than amphotericin B. The 5-halobenzimidazole derivatives could be considered promising broad-spectrum antimicrobial candidates that deserve further study for potential therapeutic applications.
- Alasmary, Fatmah A.S.,Snelling, Anna M.,Zain, Mohammed E.,Alafeefy, Ahmed M.,Awaad, Amani S.,Karodia, Nazira
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supporting information
p. 15206 - 15223
(2015/09/21)
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- 2'-Substituted 5-phenylterbenzimidazoles as topoisomerase I poisons
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5-Phenylterbenzimidazole (1) is active as a topoisomerase I poison (topo I) and is cytotoxic to human tumor cells. No cross-resistance was observed for 1 when it was evaluated against the camptothecin-resistant cell line, CPT-K5. Derivatives of 1 substituted at the 2'-position, however, did exhibit cross-resistance to this cell line. The basis for the resistance of this cell line towards CPT is that it possesses a mutant form of topo I. These results suggest that substituents at the 2'-position may be in proximity to the wild-type enzyme. Therefore, we hypothesized that terbenzimidazoles with 2'-substituents could be capable of interacting with the enzyme and thereby influence activity within this class of topo I poisons. 5-Phenylterbenzimidazoles with a hydroxy, hydroxymethyl, mercapto, amino, N-benzoylaminomethyl, chloro, and trifluoromethyl group at the 2'-position were synthesized. In addition, several 2'-ethyl-5-phenylterbenzimidazoles were prepared containing either a methoxy, hydroxy, amino, or N-acetylamino group at the 2-position of the ethyl side-chain. These 2'-substituted 5-phenylterbenzimidazoles were evaluated as topo I poisons and for cytotoxic activity. The presence of a strong electron-withdrawing group at the 2'-position, such as a chloro or trifluoromethyl group, did enhance both topo I poisoning activity and cytotoxicity. Studies on the relative DNA binding affinity of 1 to its 2'-amino and 2'-trifluoromethyl derivatives did exhibit a correlation with their relative differences in biological activity. Copyright (C) 2000 Elsevier Science Ltd.
- Rangarajan, Meera,Kim, Jung Sun,Jin, Song,Sim, Sai-Peng,Liu, Angela,Pilch, Daniel S.,Liu, Leroy F.,Lavoie, Edmond J.
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p. 1371 - 1382
(2007/10/03)
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- Heterocyclic topoisomerase poisons
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The invention provides a topoisomerase poison of formula I: wherein R1-R8 have any of the meanings defined in the specification, or a pharmaceutically acceptable salt thereof, as well as pharmaceutical compositions comprising a compound of formula I or a salt thereof, intermediates useful for preparing a compound of formula I, and therapeutic methods comprising administering a compound of formula I or a salt thereof.
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