- Bisulfite Addition Compounds as Substrates for Reductive Aminations in Water
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Highly valued products resulting from reductive aminations utilizing shelf-stable bisulfite addition compounds of aldehydes can be made under aqueous micellar catalysis conditions. Readily available α-picolineborane serves as the stoichiometric hydride source. Recycling of the aqueous reaction medium is easily accomplished, and several applications to targets in the pharmaceutical industry are documented.
- Bailey, J. Daniel,Iyer, Karthik S.,Leahy, David K.,Li, Xiaohan,Lipshutz, Bruce H.,Thakore, Ruchita R.
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supporting information
p. 7205 - 7208
(2021/09/22)
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- Synthesis, in vitro antiprotozoal activity, molecular docking and molecular dynamics studies of some new monocationic guanidinobenzimidazoles
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A series of monocationic new guanidinobenzimidazole derivatives were prepared in a four step process starting from 2-nitro-1,4-phenylendiamine. Their antiparasitic activity against Plasmodium falciparum, Trypanosoma brucei rhodesiense, Trypanosoma cruzi and Leishmania donovani were evaluated in vitro. Two out of 20 tested monocationic compounds (7, 14) showed close activity with reference drug chloroquine against P. Falciparum. To understand the interactions between DNA minor groove and in vitro active compounds (7, 14) molecular docking studies were carried out. Stability and binding energies of DNA-ligand complexes formed by DNA with compounds 7 and 14 were measured by molecular dynamics simulations throughout 200 ns time. Root mean square deviation (RMSD) values of the ligands remained stable below 0.25 mm and root mean square fluctuation (RMSF) values of the active site residues with which it interacted decreased compared to the apo form. All compounds exhibited theoretical absorption, distribution, metabolism and excretion (ADME) profiles conforming to Lipinski's and Ghose's restrictive rules.
- Doganc, Fatima,Celik, Ismail,Eren, Gokcen,Kaiser, Marcel,Brun, Reto,Goker, Hakan
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- Synthesis, bioevaluation and docking studies of some 2-phenyl-1H-benzimidazole derivatives as anthelminthic agents against the nematode Teladorsagia circumcincta
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Gastrointestinal nematode infections are the main diseases in herds of small ruminants. Resistance to the main established drugs has become a worldwide problem. The purpose of this study is to obtain and evaluate the in vitro ovicidal and larvicidal activity of some 2-phenylbenzimidazole derivatives on susceptible and resistant strains of Teladorsagia circumcincta. Compounds were prepared by known procedures from substituted o-phenylenediamines and arylaldehydes or intermediate sodium 1-hydroxyphenylmethanesulfonate derivatives. Egg Hatch Test (EHT), Larval Mortality Test (LMT) and Larval Migration Inhibition Test (LMIT) were used in the initial screening of compounds at 50 μM concentration, and EC50 values were determined for the most potent compounds. Cytotoxicity evaluation of compounds was conducted on human Caco-2 and HepG2 cell lines to calculate their Selectivity Indexes (SI). At 50 μM concentration, nine out of twenty-four compounds displayed more than 98% ovicidal activity on a susceptible strain, and four of them showed more than 86% on one resistant strain. The most potent ovicidal benzimidazole (BZ) 3 showed EC50 = 6.30 μM, for the susceptible strain, while BZ 2 showed the lowest EC50 value of 14.5 μM for the resistant strain. Docking studies of most potent compounds in a modelled Teladorsagia tubulin indicated an inverted orientation for BZ 1 in the colchicine binding site, probably due to its fair interaction with glutamic acid at codon 198, which could justify its inactivity against the resistant strain of T. circumcincta.
- Escala, Nerea,Valderas-García, Elora,Bardón, María álvarez,Gómez de Agüero, Verónica Castilla,Escarcena, Ricardo,López-Pérez, José Luis,Rojo-Vázquez, Francisco A.,San Feliciano, Arturo,Bala?a-Fouce, Rafael,Martínez-Valladares, María,Olmo, Esther del
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- Benzimidazole derivatives as potent and isoform selective tumor-associated carbonic anhydrase IX/XII inhibitors
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We describe the synthesis of a series of 2-arylbenzimidazole derivatives bearing sulfonamide functionality (4a–d, 7a–c and 10) as well as hydroxamic acid (15a–b), carboxylic acid (16a–b), carboxamide (17a–b) and boronic acid (22a–b and 26) functionalities, which act as human carbonic anhydrase (hCA, EC 4.2.1.1) inhibitors. The newly synthesized benzimidazole derivatives were evaluated against 4 physiologically relevant CA isoforms (hCA I, II, IX, and XII), and especially the sulfonamide-containing benzimidazoles demonstrated intriguing inhibitory activity against tumor associated CA IX and XII with KI values in the range of 5.2–29.3 nM and 9.9–41.7 nM, respectively. Notably, compound 4c was the most potent and selective CA IX (KI = 6.6 nM) and XII (KI = 9.9 nM) inhibitor with a significant selectivity ratio over cytosolic CA I and II isoforms in the range of 3.4–25.2. In addition, compounds having hydroxamic acid (15a-b) or carboxylic acid (16a-b) functionalities resulted in greater selectivity ratios for CA IX/XII over CAI/II in the range of 4.1–121.5 although with KI values in lower micromolar potency (KIs = 0.36–0.85 μM for CA IX/XII).
- ?al??kan, Burcu,Banoglu, Erden,Gür Maz, Tu??e,Nocentini, Alessio,Supuran, Claudiu T.,Uslu, Azize Gizem
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- 1 H -Benzimidazole-5-carboxamidine derivatives: Design, synthesis, molecular docking, DFT and antimicrobial studies
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In this study, 15 new N-(cyclohexyl)-2-substituted-1H-benzimidazole-5-carboxamidine derivatives that could be new antimicrobial agents were synthesized and their antimicrobial activities were determined using the microdilution method. Some of the derivatives showed significant efficacy against MRSA and VREF with an MIC value of 8 μg mL-1 compared to reference drugs. Molecular docking studies of the compounds against PBP4 and active and allosteric regions of PBP2a were performed and estimated ADME profiles were calculated. The nitrogens of the amidine group of M7, one of the most effective antimicrobial compounds compared to reference drugs, formed two separate hydrogen bonds with ASP275 (1.77 ?) and ASP295 (1.83 ?) in the allosteric region of PBP2a. Geometric optimization parameters, MEP analysis, and HUMO and LUMO quantum parameters of M7 were calculated using DFT/B3LYP theory and the 6-311G(d,p) basis set and the results are displayed.
- Erol, Meryem,Celik, Ismail,Temiz-Arpaci, Ozlem,Goker, Hakan,Kaynak-Onurdag, Fatma,Okten, Suzan
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p. 21309 - 21317
(2020/12/31)
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- Facile utilisation of aldehyde bisulfite adducts: Synthesis of (E)-1,2- diphenylethenes
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Background: A one-pot coupling reaction of aldehyde bisulfite adducts was developed for McMurry reaction using Zn-TiCl4 in 1,4-dioxane solvent medium. The treatment of sodium hydroxy(phenyl)methane sulfonate (2a) with TiCl4 in 1,4-dioxane favoured the deprotection of the bisulfite adduct 2a, and the in situ regeneration of benzaldehyde (1a) underwent reductive coupling to afford stilbene 3a in a relatively good yield, thus leading to an improved synthesis of a series of (E)-1,2- diphenylethenes 3. The present approach provides a new solution to the inherent instability of aldehydes and also provides a direct access to C'C bond formation for the synthesis of 1,2-diphenylethenes from aryl aldehyde bisulfite adducts. Methods: All reactions were performed at 70-80o and the synthesized compounds were characterized by IR, 1H NMR, 13C NMR, and mass spectrometric techniques. Results: The present approach provides a new solution to the instability of aldehydes and also provides a direct access to C'C bond formation for the synthesis of 1,2-diphenylethenes from aryl aldehyde bisulfite adducts. Conclusion: In the present work, we have reported an efficient method for the synthesis of 1,2- diphenylethene derivatives. Aldehydes are commonly used as the starting materials in the McMurry reaction, which affords the stilbene derivatives, the core skeleton of various valuable compounds. To increase the stability of the aldehydes, bisulfite adducts are usually employed, but the deprotection process causes loss of process efficiency. To address this issue, we developed a method based on the single-pot reaction of aromatic bisulfite adduct using TiCl4/Zn in 1,4-dioxane.
- Vinay Kumar,Jaganmohan,Sandeep Reddy,Mohanty, Sandeep,Kumar, Jaydeep,Rao, Venkateswara
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p. 109 - 114
(2017/04/03)
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- Antituberculosis agents bearing the 1,2-disubstituted benzimidazole scaffold
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Abstract: The emergence of drug-resistant strains in recent years has fueled the epidemic of tuberculosis. This necessitates the development of new chemical scaffolds to curb resistant tuberculosis for effective control of this disease. In this study, we have designed and synthesized two series of benzimidazole derivatives. Their antimycobacterial activities were initially evaluated using Mycobacterium tuberculosis H37RV strains. The most potent analog (6h) was further assessed using various drug-resistant M. tuberculosis strains. This report described the importance of benzimidazoles as new antitmycobacterial agents targeting both the M. tuberculosis H37RV as well as the drug-resistant-tuberculosis strains. The trifluoromethyl group which was essential for antimycobacterial activity was also highlighted. Graphical Abstract: Two series of benzimidazole derivatives and their antimycobacterial activities were evaluated using M. tuberculosis H37RV (MTB-H37RV) strains. Compound 6h was identified as the most potent among all synthesized compounds. The most potent analog was further assessed using various drug-resistant MTB strains. In addition, the trifluoromethyl was identified as an important substitution in giving good antimycobacterial effect. [InlineMediaObject not available: see fulltext.]
- Yeong, Keng Yoon,Ang, Chee Wei,Ali, Mohamed Ashraf,Osman, Hasnah,Tan, Soo Choon
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p. 770 - 778
(2017/03/06)
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- Synthesis of 3-Formylbenzenesulfonyl Chloride Derivatives
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A synthetic route to 3-formylbenzenesulfonyl chloride derivatives from the corresponding benzaldehydes has been developed. The key step in this procedure is the conversion of aldehyde bisulfite adducts to target compounds via a two-stage reaction in the presence of Na 2 SO 4. A series of 3-formylbenzenesulfonyl chloride derivatives were prepared by this method and identified by chemical derivatization method.
- Bao, Xuefei,Liu, Ziao,Liang, Xinjie,Song, Dake,Shi, Tao,Zhao, Xuan,Bao, Changshun,Chen, Guoliang
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p. 3165 - 3170
(2017/07/12)
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- Potent sirtuin inhibition with 1,2,5-trisubstituted benzimidazoles
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Two series of compounds were synthesized based on the benzimidazole scaffold. The compounds were subsequently screened for their SIRT1, SIRT2 and SIRT3 activities. Three of the compounds showed good inhibitory activity against SIRT2 in this study with the most potent compound (5i) having an IC50 value of 2.9 μM. Molecular docking analysis demonstrated that 5i was able to inhibit SIRT2 by displacing the co-factor NAD+ in the active site. This was further confirmed experimentally by ligand-NAD+ competitive assay.
- Yoon,Osman,Choon
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p. 2094 - 2099
(2016/11/18)
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- Reduction of Weinreb amides to aldehydes under ambient conditions with magnesium borohydride reagents Dedicated to the memory of Professor Sheldon Shore
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Chloromagnesium dimethylaminoborohydride (ClMg+ [H3BNMe2]-, MgAB) is an analogue of the versatile lithium dialkylaminoborohydrides (LAB reagents), prepared by the reaction of dimethylamine-borane with methylmagnesium chloride. MgAB is a partial reducing agent for Weinreb amides under ambient conditions and is complementary to the commonly utilized lithium aluminum hydride (LiAlH4) and diisobutylaluminum hydride (DIBAL) reagents, while exhibiting enhanced chemoselectivity. To prevent over-reduction, the aldehyde products are readily isolated in good yields by forming the sodium bisulfite adducts. Aldehyde products can both be stored and later used as the bisulfite adducts, or can be regenerated from the bisulfite adducts by treatment with aqueous formaldehyde.
- Bailey, Christopher L.,Clary, Jacob W.,Tansakul, Chittreeya,Klabunde, Lucas,Anderson, Christopher L.,Joh, Alexander Y.,Lill, Alexander T.,Peer, Natalie,Braslau, Rebecca,Singaram, Bakthan
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supporting information
p. 706 - 709
(2015/01/30)
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- Synthesis and evaluation of antimycobacterial activity of new benzimidazole aminoesters
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Abstract A total of 51 novel benzimidazoles were synthesized by a 4-step reaction starting from basic compound 4-fluoro-3-nitrobenzoic acid under relatively mild reaction conditions. The structure of the novel benzimidazoles was confirmed by mass spectra as well as 1H NMR spectroscopic data. Out of the 51 novel synthesized compounds, 42 of them were screened for their antimycobacterial activity against Mycobacterium tuberculosis H37Rv strain using BacTiter-Glo Microbial Cell Viability (BTG) method. Results of activity screened using Alamar Blue method was also provided for comparison purposes. Two of the novel benzimidazoles synthesized showed moderately good activity with IC50 of less than 15 μM. Compound 5g, ethyl 2-(4-(trifluoromethyl)phenyl)-1-(2-morpholinoethyl)-1H-benzo[d]imidazole-5-carboxylate, was found to be the most active with IC50 of 11.52 μM.
- Yoon, Yeong Keng,Ali, Mohamed Ashraf,Wei, Ang Chee,Choon, Tan Soo,Ismail, Rusli
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p. 614 - 624
(2015/03/18)
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- Phosphoryl chloride mediated synthesis of 5-arylidene-2,4- thiazolidinediones derivatives via aromatic bisulfite adducts
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The carbon-carbon bond formation by the condensation of bisulfite adduct of aromatic aldehydes with thiazolidine-2, 4-dione to furnish 5-arylidene-2,4- thiazolidinedione's has been investigated. This novel methodology was applied to convert substituted aryl bisulfite adducts to corresponding 5-arylidene-2,4-thiazolidinedione's with POCl3 in less-polar solvents such as toluene, chlorobenzene and o-xylene. 5-(4-methoxybenzylidene) thiazolidine-2,4-dione and 5-(4-ethoxybenzylidene)thiazolidine-2,4-dione were obtained in good yields.
- Mohanty, Sandeep,Reddy. G, Sandeep,Karmakar, Arun Chandra
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p. 197 - 202
(2014/05/20)
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- Direct reductive alkylation of amine hydrochlorides with aldehyde bisulfite adducts
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A mild procedure for the direct reaction of aromatic and aliphatic aldehyde bisulfite adducts with primary and secondary amine hydrochlorides in the presence of sodium cyanoborohydride in methanol is reported.
- Barniol-Xicota, Marta,Turcu, Andreea L.,Codony, Sandra,Escolano, Carmen,Vázquez, Santiago
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supporting information
p. 2548 - 2550
(2014/05/06)
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- Synthesis and evaluation of novel benzimidazole derivatives as sirtuin inhibitors with antitumor activities
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A total of 15 novel benzimidazole derivatives were designed, synthesized and evaluated for their SIRT1 and SIRT2 inhibitory activity. All compounds showed better inhibition on SIRT2 as compared to SIRT1. Among these, compound 5j displayed the best inhibitory activity for SIRT1 (IC50 = 58.43 μM) as well as for SIRT2 (IC50 = 45.12 μM). Cell cytotoxicity assays also showed that compound 5j possesses good antitumor activity against two different cancer cell lines derived from breast cancer (MCF-7 and MDA-MB-468). A simple structure-activity-relationship (SAR) study of the newly synthesized benzimidazole derivatives was also discussed.
- Yoon, Yeong Keng,Ali, Mohamed Ashraf,Wei, Ang Chee,Choon, Tan Soo,Osman, Hasnah,Parang, Keykavous,Shirazi, Amir Nasrolahi
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p. 703 - 710
(2014/01/23)
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- Benzimidazole derivatives: Synthesis, leishmanicidal effectiveness, and molecular docking studies
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Leishmanolysin GP63 is a zinc metalloprotease, expressed at the surface of Leishmania promastigotes. Studies on this protein are hindered as only a limited number of effective non-toxic inhibitors of this drug target are known. Present study describes the identification of a variety of 2-aryl- and 5-nitro-2-arylbenzimidazoles as new GP63 inhibitors. All the compounds were tested for in vitro activity against the promastigote form of Leishmania major and showed very good activity. 2-(Thiophen-2-yl)-1H-benzimidazole (19) and 2-(1H-indol-3-yl)-5-nitro-1H-benzimidazole (34) with IC50 value of 0.62 μg/mL were identified as lead of this library. Molecular docking studies were performed on binding site of GP63 to study the binding mode of compounds. The results of both in vitro and in silico studies clearly indicated that benzimidazoles may serve as new drug candidates in the combat against leishmaniasis.
- Shaukat, Awais,Mirza, Hira M.,Ansari, Amna H.,Yasinzai, Masoom,Zaidi, Sohail Z.,Dilshad, Sana,Ansari, Farzana L.
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p. 3606 - 3620
(2013/07/26)
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- Synthesis, characterization, and molecular docking analysis of novel benzimidazole derivatives as cholinesterase inhibitors
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Two series of novel acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitors containing benzimidazole core structure were synthesized by a four-step reaction pathway starting from 4-fluoro-3-nitrobenzoic acid as the basic compound. The structure of the novel benzimidazoles was characterized and confirmed by the elemental and mass spectral analyses as well as 1H NMR spectroscopic data. Of the 34 novel synthesized compounds, three benzimidazoles revealed AChE inhibition with IC50 10 lM. The highest inhibitory activity (IC50 = 5.12 lM for AChE and IC50 = 8.63 lM for BChE) corresponds to the compound 5IIc (ethyl 1-(3-(1H-imidazol-1-yl)propyl)-2- (4-nitrophenyl)-1H-benzo[d]imidazole-5-carboxylate). The relationship between lipophilicity and the chemical structures as well as their limited structure-activity relationship was discussed.
- Yoon, Yeong Keng,Ali, Mohamed Ashraf,Wei, Ang Chee,Choon, Tan Soo,Khaw, Kooi-Yeong,Murugaiyah, Vikneswaran,Osman, Hasnah,Masand, Vijay H.
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- 5-Acetyl-2-arylbenzimidazoles as antiviral agents. Part 4
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Within a project aimed at discovering new Flaviviridae inhibitors, new variously substituted 2-phenylbenzimidazoles were synthesized and evaluated in cell-based assays for cytotoxicity and antiviral activity against viruses representatives of the three genera of the Flaviviridae family, i.e.: Pestivirus (BVDV), Flavivirus (YFV) and Hepacivirus (HCV). Title compounds were also tested against RNA viruses representative of other single-stranded, positive-sense (ssRNA+) negative-sense (RNA-), or double-stranded (dsRNA) genomes, as well as against representatives of two DNA virus families. Nine compounds showed activity against BVDV (EC50 = 0.8-8.0 μM), compound 31 being the most potent (EC50 = 0.80 μM) and selective (SI = CC50/EC50 = >100). When tested in an HCV replicon assay, compound 31 resulted again the most potent, displaying an EC50 value of 1.11 μM and an SI of 100. Besides inhibiting BVDV, two compounds (35 and 38) showed a moderate activity also against YFV (EC 50 = 13 μM). Interestingly, 35 was moderately active also against RSV (EC50 = 25 μM).
- Vitale, Gabriella,Corona, Paola,Loriga, Mario,Carta, Antonio,Paglietti, Giuseppe,Giliberti, Gabriele,Sanna, Giuseppina,Farci, Pamela,Marongiu, Maria Elena,La Colla, Paolo
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body text
p. 83 - 97
(2012/08/08)
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- Novel clarithromycin analogs with C-4′′ 2-arylbenzimidazolyl bishydrazide side chain: Synthesis and antibacterial evaluation
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A series of novel 4′′-O-2-arylbenzimidazolyl derivatives of clarithromycin were synthesized and evaluated. These 4′′-O-2- arylbenzimidazolyl derivatives demonstrated excellent activity against erythromycin-susceptible strains and showed remarkably improved activity against erythromycin-resistant strains compared with the references. In particular, compound 7c, which possesses the terminal 2-(2-methoxyphenyl)benzimidazolyl group on the C-4′′ bishydrazide side chain, not only presented the most potent activity against erythromycin-susceptible Streptococcus pneumoniae ATCC49619 and Staphylococcus aureus ATCC25923, exhibiting 4-fold and 4-fold higher efficacy than the parent clarithromycin, but also displayed the highest activity against erythromycin-resistant Streptococcus pneumoniae expressing the mef gene and the erm gene, which was 133-fold and 32-fold better than clarithromycin or azithromycin, respectively.
- Qi, Yunkun,Ma, Ruixin,Li, Xin,Hu, Yue,Ma, Siti,Cong, Chao,Ma, Xiaodong,Cui, Wenping,Ma, Shutao
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experimental part
p. 966 - 971
(2012/07/01)
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- Synthesis and in vitro antimicrobial activity of some novel substituted benzimidazole derivatives having potent activity against MRSA
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The novel benzimidazole derivatives (3, 5, 8, 9, 12-14, 18-41) were prepared in this paper and the antimicrobial activities of these compounds against Staphylococcus aureus, methicillin-resistant S. aureus (MRSA, standard and clinical isolates), Bacillus subtilis, Escherichia coli and Candida albicans were evaluated. Compounds 24-26 which have no substitution of N-1 position displayed better antibacterial activities than those of standards (ciprofloxacin, ampicillin and sultamicillin) against both the drug-resistant bacteria (MRSA, standard and clinical isolates). These derivatives (24-26), 2,5,6-trihalogenobenzimidazole analogues (8, 12), 5,6-dichloro-2-amino derivative (13), and 5-chloro-2-(4-benzyloxyphenyl)benzimidazole (35) exhibited the most potent antibacterial activity with MIC 3.12 μg/ml against S. aureus.
- Tuncbilek, Meral,Kiper, Tulug,Altanlar, Nurten
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experimental part
p. 1024 - 1033
(2009/09/06)
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- Synthesis and potent antibacterial activity against MRSA of some novel 1,2-disubstituted-1H-benzimidazole-N-alkylated-5-carboxamidines
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A series of 28 novel 1,2-disubstituted-1H-benzimidazole-N-alkylated-5- carboxamidine derivatives were synthesized and evaluated for in vitro antibacterial activities against Staphylococcus aureus and methicillin resistant S. aureus (MRSA) by the tube dilution method. The results showed that compounds 45-46 and 55-57, having 3,4-dichloro substituted phenyl at the position C-2, of N-bulky alkyl substituted benzimidazolecarboxamidines exhibited the greatest activity with MIC values of 1.56-0.39 μg/ml.
- Goeker, Hakan,Oezden, Seckin,Yildiz, Sulhiye,Boykin, David W.
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p. 1062 - 1069
(2007/10/03)
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- A new, mild, and rapid transformation of acylals to bisulfites in one-pot synthesis by bismuth (III) nitrate pentahydrate
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Direct conversion of acylals to the corresponding bisulfites can be easily performed in the presence of bismuth (III) nitrate pentahydrate in ethanol at room temperature in good yields. Copyright Taylor & Francis Inc.
- Khodaei, Mohammad Mehdi,Kordestani, Davood
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p. 2403 - 2405
(2007/10/03)
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- Synthesis and antimicrobial activity of some new 2-phenyl-N-substituted carboxamido-1H-benzimidazole derivatives
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Some 1H-benzimidazole-carboxamide derivatives were prepared and their antimicrobial activities against Staphyloccus aureus, Escherichia coli and Candida albicans evaluated. Compounds 18, 22, and 25 exhibited the best activity against Candida albicans.
- Goeker, Hakan,Tuncbilek, Meral,Suezen, Sibel,Kus, Canan,Altanlar, Nurten
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p. 148 - 152
(2007/10/03)
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- Kinetics, Thermodynamics, and Mechanism of the Formation of Benzaldehyde-S(IV) Adducts
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The kinetics and mechanism of the formation of α-hydroxyphenylmethanesulfonate (HPMS) by the addition of bisulfite to benzaldehyde were studied at low pH.A three-term rate law was observed as d/dt = (k1α2 + (k2 + k3KH- (H+))α1)t where α1 = ->/, α2 = 2->/, and KH is the proton association constant of benzaldehyde.The rate-limiting steps of each term appeared to be the nucleophilic attack of SO32- on the carbonyl carbon of benzaldehhyde, the attack of HSO3- on the carbonyl carbon, and the attack by HSO3- on the protonated carbon of the carbocation, C6H5C+H(OH), respectively.Over the pH range of most natural systems, only the k1 and k2 steps contribute to adduct formation while the k3 term becomes important for pH 1 = (2.15 +/- 0.09) * 104 M-1 s-1, k2 = (0.71 +/- 0.03) M-1 s-1, k3 ca./= 2.5 * 107 M-1 s-1.Para-substitution on the benzaldehyde ring resulted in a slight increase in reactivity for p-NO2- and p-Cl-, and a decrease for p-OH-, p-OCH3-, and p-CH3-C6H5CHO.The equilibrium association constant, K = ->/-> , at 25 deg C was determined to be 4.8 (+/-0.8) * 103 at μ = 0.1 M and 0.98 (+/-0.11) * 103 M-1 at μ = 1.0 M. ΔH deg and ΔS deg were determined to be -64.6 kJ mol-1 and -146 J mol-1 deg-1, respectively.
- Olson, Terese M.,Boyce, Scott D.,Hoffmann, Michael R.
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p. 2482 - 2488
(2007/10/02)
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- Nucleophilic Addition to Double Bond Systems, II. Kinetics of the Reaction of Sulfit with Aromatic Aldehydes
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The rate constants of the addition of sulfit to aromatic aldehydes have been measured directly at pH=7 using stopped flow and temperature jump methods. - Keywords: Aromatic aldehydes; Nucleophile addition; Stopped flow; Temperature jump.
- Basu, Sukumar,Schuster, Peter,Wolschann, Peter
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p. 421 - 428
(2007/10/02)
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- A NOVEL AND VERSATILE SEPARATION METHOD FOR ALDEHYDES
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An aqueous solution of sodium ε-amino-n-caproate can be used for efficient and simple separation of aldehydes, overcoming the difficulties associated with the NaHSO3 method.Keywords - separation of aldehydes; Schiff base of amino acid; ω-amino acid; sodium ε-amino-n-caproate; sodium bisulfite adduct of aldehydes
- Ohta, Shunsaku,Okamoto, Masao
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p. 1917 - 1919
(2007/10/02)
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