- Bio-evaluation of fluoro and trifluoromethyl-substituted salicylanilides against multidrug-resistant S. aureus
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Methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Staphylococcus aureus (VRSA) are primary causes of skin and soft tissue infections worldwide. To address the emergency caused due to increasing multidrug-resistant (MDR) bacterial infections, a series of novel fluoro and trifluoromethyl-substituted salicylanilide derivatives were synthesized and their antimicrobial activity was investigated. MIC data reveal that the compounds inhibited S. aureus specifically (MIC 0.25–64 μg/mL). The in vitro cytotoxicity of compounds with MIC 1 μg/mL against Vero cells led to identification of four compounds (20, 22, 24 and 25) with selectivity index above 10. These four compounds were tested against MDR S. aureus panel. Remarkably, 5-chloro-N-(4’-bromo-3’-trifluoromethylphenyl)-2-hydroxybenzamide (22) demonstrated excellent activity against nine MRSA and three VRSA strains with MIC 0.031–0.062 μg/mL, which is significantly better than the control drugs methicillin and vancomycin. The comparative time–kill kinetic experiment revealed that the effect of bacterial killing of 22 is comparable with vancomycin. Compound 22 did not synergize with or antagonize any FDA-approved antibiotic and reduced pre-formed S. aureus biofilm better than vancomycin. Overall, study suggested that 22 could be further developed as a potent anti-staphylococcal therapeutic. [Figure not available: see fulltext.]
- Akhir, Abdul,Ansari, Shabina B.,Chopra, Sidharth,Kaul, Grace,Lal, Jhajan,Reddy, Damodara N.
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p. 2301 - 2315
(2021/10/30)
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- Zn(ii)@TFP-DAQ COF: An efficient mesoporous catalyst for the synthesis of: N -methylated amine and carbamate through chemical fixation of CO2
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Selective N-methylation and carbamate formation reactions were demonstrated via the chemical incorporation of CO2 using a Zn-loaded TFP-DAQ COF (covalent organic framework) as an active catalyst under mild reaction conditions. The selective N-methylation and N-formylation reactions were performed by simply varying the type of solvent. The Zn(ii)@TFP-DAQ COF catalyst was characterized via different characterization techniques such as PXRD, FTIR, UV-vis, N2 adsorption-desorption studies, FESEM and TEM. The catalyst material showed pores in the mesoporous region with a high surface area of 1117.375 m2 g-1. The as-synthesized material was applied as a cheap catalyst for the N-methylation of secondary amines and in carbamate formation reactions with high yields of the desired products up to 98.5% and 97%, respectively, with >99% selectivity. The catalyst was found to be completely heterogeneous and reusable for multiple reaction cycles.
- Sarkar, Priyanka,Chowdhury, Arpita Hazra,Riyajuddin, Sk.,Biswas, Surajit,Ghosh, Kaushik,Islam, Sk. Manirul
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p. 744 - 752
(2020/01/31)
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- One stone two birds: Cobalt-catalyzed in situ generation of isocyanates and benzyl alcohols for the synthesis of N-aryl carbamates
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An efficient method for the synthesis of N-aryl carbamates from N-Boc-protected amines has been developed. The cobalt-catalyzed in situ generation of isocyanates from N-Boc-protected amines and benzyl alcohols from benzyl formates has been achieved for the first time, which in turn furnished the corresponding benzyl carbamates in moderate to high yields. The reaction was catalyzed by CoI2 with tris-(4-dimethylaminophenyl)-phosphine as the ligand and zinc powder as the reductant. The developed reaction conditions were found to be compatible for aromatic amines with both electron-donating and -withdrawing substituents.
- Li, Sida,Khan, Ruhima,Zhang, Xia,Yang, Yong,Wang, Zheting,Zhan, Yong,Dai, Yuze,Liu, Yue-E,Fan, Baomin
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p. 5891 - 5896
(2019/06/24)
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- Modified Graphene Oxide Based Zinc Composite: an Efficient Catalyst for N-formylation and Carbamate Formation Reactions Through CO2 Fixation
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Catalytic fixation of CO2 through chemical reactions is always a challenging task of synthetic chemistry. This paper represents the design and synthesis of an eco-friendly low cost zinc metal containing heterogeneous catalyst of aminically modified Graphene Oxide. Characterization of the catalyst has been carried out by Raman and FTIR spectra, AAS, XRD, TEM, SEM, EDX and N2 adsorption desorption studies. It was found that the catalyst was very proficient for the CO2 fixation through N-formylation and carbamate formation reactions of amines. Catalytic N-formylation reaction of both aromatic and aliphatic amines gave high yield of corresponding formylated products in presence of polymethylhydrosiloxane (PMHS) as reducing agent under 1 bar CO2 pressure and mild temperature. Formation of carbamates from aniline or its derivatives and alkyl/aryl bromide with good product selectivity was also achieved under same CO2 pressure in presence of our synthesized catalyst at room temperature with solvent-free condition. The catalyst is reusable and e?cient even after six cycles.
- Khatun, Resmin,Biswas, Surajit,Islam, Sarikul,Biswas, Imdadul Haque,Riyajuddin, Sk,Ghosh, Kaushik,Islam, Sk Manirul
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supporting information
p. 1303 - 1312
(2019/01/25)
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- A highly efficient heterogeneous copper-catalyzed chlorodeboronation of arylboronic acids leading to chlorinated arenes
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A highly efficient heterogeneous copper-catalyzed chlorodeboronation of arylboronic acids with inexpensive N-chlorosuccinimide (NCS) was achieved in MeCN in the presence of 10 mol% of l-proline-functionalized MCM-41-immobilized copper(i) complex [MCM-41-l-proline-CuCl] under mild conditions, yielding a variety of aryl chlorides in excellent yields. This method proved to be tolerant of a broad range of functional groups and particularly useful for the conversion of electron-deficient arylboronic acids to aryl chlorides, a transformation that is inefficient without copper catalysis. This heterogeneous copper catalyst can be recovered by a simple filtration of the reaction solution and recycled for at least 10 times without any decreases in activity.
- He, Wen,Zhang, Rongli,Cai, Mingzhong
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p. 764 - 770
(2017/01/13)
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- A synthetic approach to N -aryl carbamates via copper-catalyzed Chan-Lam coupling at room temperature
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A mild and efficient synthesis of N-arylcarbamates was achieved by reacting azidoformates with boronic acids in the presence of 10 mol % of copper chloride catalyst. The reaction proceeds readily in an open flask at room temperature without additional base, ligand, or additive. Rapid access to urea analogues via a two-step one-pot procedure is enabled by reacting N-arylcarbamates with aluminum-amine complexes. In addition, among several boronic acid derivatives prepared, dimethylphenyl boronate was found to react rapidly in its reaction with benzyl azidoformate, invoking in situ generation of this species in the catalytic cycle.
- Moon, Soo-Yeon,Kim, U. Bin,Sung, Dan-Bi,Kim, Won-Suk
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p. 1856 - 1865
(2015/02/19)
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- Salicylanilide diethyl phosphates as cholinesterases inhibitors
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Based on the presence of dialkyl phosphate moiety, we evaluated twenty-seven salicylanilide diethyl phosphates (diethyl [2-(phenylcarbamoyl)phenyl] phosphates) for the inhibition of acetylcholinesterase (AChE) from electric eel (Electrophorus electricus L.) and butyrylcholinesterase (BChE) from equine serum. Ellman's spectrophotometric method was used. The inhibitory activity (expressed as IC50 values) was compared with that of the established drugs galantamine and rivastigmine. Salicylanilide diethyl phosphates showed significant activity against both cholinesterases with IC50 values from 0.903 to 86.3 μM. IC50s for BChE were comparatively lower than those obtained for AChE. All of the investigated compounds showed higher inhibition of AChE than rivastigmine, and six of them inhibited BChE more effectively than both rivastigmine and galantamine. In general, derivatives of 4-chlorosalicylic acid showed enhanced activity when compared to derivatives of 5-halogenated salicylic acids, especially against BChE. The most effective inhibitor of AChE was O-{5-chloro-2-[(3-bromophenyl)carbamoyl]phenyl} O,O-diethyl phosphate with IC50 of 35.4 μM, which is also one of the most potent inhibitors of BChE. O-{5-Chloro-2-[(3,4-dichlorophenyl)carbamoyl]phenyl} O,O-diethyl phosphate exhibited in vitro the strongest inhibition of BChE (0.90 μM). Salicylanilide diethyl phosphates act as pseudo-irreversible cholinesterases inhibitors.
- Krtk, Martin,tpnkov, rka,Vorkov, Katarna,Vinov, Jarmila
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- Diethyl 2-(phenylcarbamoyl)phenyl phosphorothioates: Synthesis, antimycobacterial activity and cholinesterase inhibition
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A new series of 27 diethyl 2-(phenylcarbamoyl)phenyl phosphorothioates (thiophosphates) was synthesized, characterized by NMR, IR and CHN analyses and evaluated against Mycobacterium tuberculosis H37Rv, Mycobacterium avium and two strains of Mycobacterium kansasii. The best activity against M. tuberculosis was found for O-{4-bromo-2-[(3,4-dichlorophenyl)carbamoyl]phenyl} O,O-diethyl phosphorothioate (minimum inhibitory concentration of 4 iM). The highest activity against nontuberculous mycobacteria was exhibited by O-(5-chloro-2-{[4-(trifluoromethyl)phenyl]carbamoyl}- phenyl) O,O-diethyl phosphorothioate with MIC values from 16 iM. Prepared thiophosphates were also evaluated against acetylcholinesterase from electric eel and butyrylcholinesterase from equine serum. Their inhibitory activity was compared to that of the known cholinesterases inhibitors galanthamine and rivastigmine. All tested compounds showed a higher (for AChE inhibition) and comparable (for BChE inhibition) activity to that of rivastigmine, with IC50s within the 8.04 to 20.2 iM range.
- Vinsova, Jarmila,Kratky, Martin,Komloova, Marketa,Dadapeer, Echchukattula,Stipankova, Sarka,Voreakova, Katarina,Stolaoikova, Jioina
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p. 7152 - 7168
(2014/07/08)
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- Salicylanilide diethyl phosphates: Synthesis, antimicrobial activity and cytotoxicity
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A series of 27 salicylanilide diethyl phosphates was prepared as a part of our on-going search for new antimicrobial active drugs. All compounds exhibited in vitro activity against Mycobacterium tuberculosis, Mycobacterium kansasii and Mycobacterium avium strains, with minimum inhibitory concentration (MIC) values of 0.5-62.5 μmol/L. Selected salicylanilide diethyl phosphates also inhibit multidrug-resistant tuberculous strains at the concentration of 1 μmol/L. Salicylanilide diethyl phosphates also exhibited mostly the activity against Gram-positive bacteria (MICs ≥1.95 μmol/L), whereas their antifungal activity is significantly lower. The IC50 values for Hep G2 cells were within the range of 1.56-33.82 μmol/L, but there is no direct correlation with MICs for mycobacteria.
- Vin?ová, Jarmila,Kozic, Ján,Krátky, Martin,Stola?íková, Ji?ina,Mandíková, Jana,Trejtnar, Franti?ek,Buchta, Vladimír
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p. 728 - 737
(2014/01/23)
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- Reaction of organozinc halides with aryl isocyanates
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Reformatsky reagent, benzylzinc bromide or alkylzinc iodides react with aryl isocyanates directly to give corresponding N-substituted carbamates under mild reaction conditions. However, the reaction of allylzinc bromide or propargylzinc bromide with aryl isocyanates produces the corresponding N-substituted amides. The reactions provide alternative methods for the synthesis of N-substituted carbamates or amides.
- Yang, Haoran,Huang, Danfeng,Wang, Ke-Hu,Xu, Changming,Niu, Teng,Hu, Yulai
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supporting information
p. 2588 - 2593
(2013/03/28)
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- Antibacterial activity of salicylanilide 4-(trifluoromethyl)benzoates
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The development of novel antimicrobial agents represents a timely research topic. Eighteen salicylanilide 4-(trifluoromethyl)benzoates were evaluated against Mycobacterium tuberculosis, M. avium and M. kansasii, eight bacterial strains including methicillin-resistant Staphylococcus aureus (MRSA) and for the inhibition of mycobacterial isocitrate lyase. Some compounds were further screened against drug-resistant M. tuberculosis and for their cytotoxicity. Minimum inhibitory concentrations (MICs) for all mycobacterial strains were within 0.5-32 μmol/L, with 4-chloro-2-[4- (trifluoromethyl)phenylcarbamoyl] phenyl 4-(trifluoromethyl)benzoate superiority. Grampositive bacteria including MRSA were inhibited with MICs ≥ 0.49 μmol/L, while Gramnegative ones were much less susceptible. Salicylanilide 4-(trifluoromethyl)benzoates showed significant antibacterial properties, for many strains being comparable to standard drugs (isoniazid, benzylpenicillin) with no cross-resistance. All esters showed mild inhibition of mycobacterial isocitrate lyase and four compounds were comparable to 3-nitropropionic acid without a direct correlation between in vitro MICs and enzyme inhibition.
- Kratky, Martin,Vinsova, Jarmila,Novotna, Eva,Mandikova, Jana,Trejtnar, Frantisek,Stolarikova, Jirina
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p. 3674 - 3688
(2013/06/05)
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- New derivatives of salicylamides: Preparation and antimicrobial activity against various bacterial species
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Three series of salicylanilides, esters of N-phenylsalicylamides and 2-hydroxy-N-[1-(2-hydroxyphenylamino)-1-oxoalkan-2-yl]benzamides, in total thirty target compounds were synthesized and characterized. The compounds were evaluated against seven bacterial and three mycobacterial strains. The antimicrobial activities of some compounds were comparable or higher than the standards ampicillin, ciprofloxacin or isoniazid. Derivatives 3f demonstrated high biological activity against Staphylococcus aureus (≤0.03 μmol/L), Mycobacterium marinum (≤0.40 μmol/L) and Mycobacterium kansasii (1.58 μmol/L), 3g shows activity against Clostridium perfringens (≤0.03 μmol/L) and Bacillus cereus (0.09 μmol/L), 3h against Pasteurella multocida (≤0.03 μmol/L) and M. kansasii (≤0.43 μmol/L), 3i against methicillin-resistant S. aureus and B. cereus (≤0.03 μmol/L). The structure-activity relationships are discussed for all the compounds.
- Pauk, Karel,Zadrazilova, Iveta,Imramovsky, Ales,Vinsova, Jarmila,Pokorna, Michaela,Masarikova, Martina,Cizek, Alois,Jampilek, Josef
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p. 6574 - 6581
(2013/10/22)
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- Antifungal activity of salicylanilides and their esters with 4-(trifluoromethyl)benzoic acid
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Searching for novel antimicrobial agents still represents a current topic in medicinal chemistry. In this study, the synthesis and analytical data of eighteen salicylanilide esters with 4-(trifluoromethyl)benzoic acid are presented. They were assayed in vitro as potential antimycotic agents against eight fungal strains, along with their parent salicylanilides. The antifungal activity of the presented derivatives was not uniform and moulds showed a higher susceptibility with minimum inhibitory concentrations (MIC) ≥ 0.49 μmol/L than yeasts (MIC ≥ 1.95 μmol/L). However, it was not possible to evaluate a range of 4-(trifluoromethyl)benzoates due to their low solubility. In general, the most active salicylanilide was N-(4-bromophenyl)-4-chloro-2- hydroxybenzamide and among esters, the corresponding 2-(4-bromophenylcarbamoyl)- 5-chlorophenyl 4-(trifluoromethyl) benzoate exhibited the lowest MIC of 0.49 μmol/L. However, the esterification of salicylanilides by 4-(trifluoromethyl)benzoic acid did not result unequivocally in a higher antifungal potency.
- Kratky, Martin,Vinsova, Jarmila
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p. 9426 - 9442
(2012/11/14)
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- Acetylcholinesterase-inhibiting activity of salicylanilide N-alkylcarbamates and their molecular docking
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A series of twenty-five novel salicylanilide N-alkylcarbamates were investigated as potential acetylcholinesterase inhibitors. The compounds were tested for their ability to inhibit acetylcholinesterase (AChE) from electric eel (Electrophorus electricus L.). Experimental lipophilicity was determined, and the structure-activity relationships are discussed. The mode of binding in the active site of AChE was investigated by molecular docking. All the discussed compounds expressed significantly higher AChE inhibitory activity than rivastigmine and slightly lower than galanthamine. Disubstitution by chlorine in C'(3,4) of the aniline ring and the optimal length of hexyl-undecyl alkyl chains in the carbamate moiety provided the most active AChE inhibitors. Monochlorination in C'(4) exhibited slightly more effective AChE inhibitors than in C'(3). Generally it can be stated that compounds with higher lipophilicity showed higher inhibition, and the activity of the compounds is strongly dependent on the length of the N-alkyl chain.
- Imramovsky, Ales,Pauk, Karel,Stepankova, Sarka,Vanco, Jan,Jampilek, Josef,Monreal-Ferriz, Juana,Vinsova, Jarmila
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p. 10142 - 10158,17
(2020/09/09)
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- Antimycobacterial assessment of salicylanilide benzoates including multidrug-resistant tuberculosis strains
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The increasing emergence especially of drug-resistant tuberculosis has led to a strong demand for new anti-tuberculosis drugs. Eighteen salicylanilide benzoates were evaluated for their inhibition potential against Mycobacterium tuberculosis, Mycobacterium avium and two strains of Mycobacterium kansasii; minimum inhibitory concentration values ranged from 0.5 to 16 μmol/L. The most active esters underwent additional biological assays. Four benzoates inhibited effectively the growth of five multidrug-resistant strains and one extensively drug-resistant strain of M. tuberculosis at low concentrations (0.25-2 μmol/L) regardless of the resistance patterns. The highest rate of multidrug-resistant mycobacteria inhibition expressed 4-chloro-2-[4- (trifluoromethyl)-phenylcarbamoyl]phenyl benzoate (0.25-1 μmol/L). Unfortunately, the most potent esters were still considerably cytotoxic, although mostly less than their parent salicylanilides.
- Kratky, Martin,Vinsova, Jarmila,Stolarikova, Jirina
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p. 12812 - 12820
(2013/02/23)
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- Photosynthesis - Inhibiting efficiency of 4-chloro-2- (chlorophenylcarbamoyl)phenyl alkylcarbamates
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A series of photosynthetic electron transport (PET) inhibitors from the group of salicylanilide alkylcarbamates was investigated. The compounds were analyzed using RP-HPLC to determine lipophilicity, and their PET inhibition was determined in spinach (Spinacia oleracea L.) chloroplasts. The site of action of the studied compounds is situated at the donor site of photosystem 2 (PS 2). Compounds substituted by chlorine in C′-3 and C′-4 of the aniline ring and the optimal length of the alkyl chain pentyl-heptyl in the carbamate moiety provided the most active PET inhibitors (IC50 inhibition 10 μmol/L). Disubstitution in C′-3,4 by chlorine caused significant PET inhibiting activity decrease. Nevertheless, for all three series of C′-3, C′-4, C′-3,4 compounds, the dependence of PET activity on lipophilicity showed to be quasi-parabolic.
- Imramovsky, Ales,Pesko, Matus,Ferriz, Juana Monreal,Kralova, Katarina,Vinsova, Jarmila,Jampilek, Josef
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supporting information; body text
p. 4564 - 4567
(2011/09/15)
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- Salicylanilide carbamates: Antitubercular agents active against multidrug-resistant Mycobacterium tuberculosis strains
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A series of 27 salicylanilide-based carbamates was prepared as a part of our ongoing search for new antituberculosis drugs. These compounds exhibited very good in vitro activity against Mycobacterium tuberculosis, Mycobacterium kansasii and Mycobacterium avium and, in particular, against five multidrug-resistant strains, with MIC values between 0.5-2 μmol/L. Moreover, they displayed moderate toxicity against intestinal cells with the selectivity index being up to 96. Furthermore, acid stability and a half-life of 43 h at pH 7.4 were shown. Thus, these novel salicylanilide derivatives are drug candidates which should be seriously consider for further screening.
- Férriz, Juana M.,Vávrová, Kate?ina,Kunc, Filip,Imramovsky, Ale?,Stola?íková, Ji?ina,Vav?íková, Eva,Vin?ová, Jarmila
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scheme or table
p. 1054 - 1061
(2010/04/24)
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- New amino acid esters of salicylanilides active against MDR-TB and other microbes
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Eleven halogenated (S)-2-(phenylcarbamoyl)phenyl 2-acetamido-3- phenylpropanoates (3a-3k) were designed and synthesized as potential antimicrobial agents. They were evaluated in vitro against some mycobacterial, bacterial and fungal strains. These compounds were active against drug-sensitive and atypical mycobacterial strains with general MIC values from 0.25 to 16 μmol/L. The most active compounds were (S)-4-chloro-2-(4-(trifluoromethyl) phenylcarbamoyl)phenyl 2-acetamido-3-phenylpropanoate (3i) and (S)-4-bromo-2-(4-(trifluoromethyl)phenylcarbamoyl)phenyl 2-acetamido-3- phenylpropanoate (3k) which exhibited activity against MDR and XDR-TB strains with MICs from 1 to 2 μmol/L. 3k was shown to be less cytotoxic with higher IC50. Some compounds exhibited low MICs on Gram-positive bacteria (MICs ≥ 0.98 μmol/L) and on fungi (MICs ≥ 3.9 μmol/L).
- Krátky, Martin,Vin?ová, Jarmila,Buchta, Vladimír,Horvati, Kata,B?sze, Szilvia,Stola?íková, Ji?ina
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experimental part
p. 6106 - 6113
(2011/01/13)
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- Salicylanilide esters of N-protected amino acids as novel antimicrobial agents
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A series of novel, highly antimicrobial salicylanilide esters of N-protected amino acids were synthesized and characterized. Their in vitro antimicrobial activity against eight fungal strains and Mycobacterium tuberculosis was determined. The compounds had the highest level of activity against Aspergillus fumigatus, Absidia corymbifera and Trichophyton mentagrophytes, and these levels were higher than that of the standard drug fluconazole. In addition, three compounds showed interesting antituberculosis activity, with inhibition ranging from 89% to 99%. (S)-4-Chloro-2-(4-trifluoromethylphenylcarbamoyl)-phenyl 2-benzyloxy-carbonylamino-propionate had the highest level of both antifungal and antimycobacterial activity. The structure-activity relationships of the new compounds are discussed.
- Imramovsky, Ales,Vinsova, Jarmila,Ferriz, Juana Monreal,Buchta, Vladimir,Jampilek, Josef
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scheme or table
p. 348 - 351
(2011/03/18)
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- Salicylanilide esterification: unexpected formation of novel seven-membered rings
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Novel benzoxazepines were prepared upon esterification of biologically active salicylanilides with some N-protected amino acids. While the desired conjugates of the salicylanilides with the amino acids were obtained when sterically more demanding amino acids were used, benzoxazepines were formed as a result of a seven-exo-trig cyclization in the case of N-protected glycine and alanine. The structures of the products were confirmed by 2D NMR methods, and further transformations of the acyclic conjugates provided additional support for the proposed mechanism of cyclization.
- Imramovsky, Ale?,Vin?ová, Jarmila,Férriz, Juana Monreal,Kune?, Ji?í,Pour, Milan,Dole?al, Martin
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p. 5007 - 5011
(2007/10/03)
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