Lysocin E, a macrocyclic peptide, exhibits potent antibacterial activity against methicillin‐resistant Staphylococcus aureus (MRSA) through a novel mechanism. The first total synthesis of lysocin E was achieved by applying a full solid‐phase strategy. The developed approach also provides rapid access to the enantiomeric, epimeric, and N‐demethylated analogues of lysocin E. Significantly, the antibacterial activity of the unnatural enantiomer was comparable to that of the natural isomer, suggesting the absence of chiral recognition in its mode of action. 相似文献
Eighteen novel 2‐(1‐aryl‐5‐methyl‐1,2,3‐triazol‐4‐yl)‐1,3,4‐oxadiazole derivatives and two acylhydrazone intermediate compounds were synthesized by various pathways starting from 1‐aryl‐5‐methyl‐1,2,3‐triazol‐4‐formhydrazide ( 1 ). All products were identified by spectroscopic analysis, and 2‐(1‐aryl‐5‐methyl‐1,2,3‐triazol‐4‐yl)‐5‐benzalthio‐1,3,4‐oxadiazole was further validated by X‐ray crystallography. Results from primary antibacterial activity tests indicated that most of the compounds were effective against E. coli, P. aeruginosa, B. subtilis and S. aureus. 相似文献
We investigated the antibacterial activity of some new macromolecules such as bis‐pyrazoline, bis‐pyrazole, bis‐pyrimidines prepared from the reaction of bis‐chalcone with thiosemicarbazide/phenyl hydrazine/guanidine hydrochloride/thiourea. All the macromolecules have been characterized by IR, 1H NMR, 13C NMR, mass and elemental analyses. The antibacterial activity of these compounds was first tested in vitro by the disc diffusion assay against two Gram‐positive and two Gram‐negative bacteria, and then the minimum inhibitory concentration was determined with the reference to standard drug chloramphenicol. The results showed that pyrazoline derivative showed better antibacterial activity on S. typhimurium and E. coli than the reference drug chloramphenicol. 相似文献
The condensation of 4‐amino‐5‐mercapto‐3‐(5‐methylisoxazol‐3‐yl)‐1,2,4‐triazole with substituted phenacyl bromide, aldehydes, p‐bromophenylisothiocyanate, aromatic carboxylic acids and oxalic acid, is described. The antibacterial activity of representative compounds was evaluated. 相似文献
Metal carboxylate compounds with nitrogen‐ and/or oxygen‐donor ligands with various carboxylate coordination modes, monodentate, bidentate and bridging bidentate, have been shown to be important from biological and chemical aspects. Five zinc ion binary compounds, diaqua‐bis‐(2‐((E )‐5‐fluoro‐2‐methyl‐1‐(4‐(methylsulfinyl)benzylidene)‐1H –inden‐3‐yl)acetato)zinc(II) ( 1 ), aqua‐bis‐(2‐((E )‐5‐fluoro‐2‐methyl‐1‐(4‐(methylsulfinyl)benzylidene)‐1H –inden‐3‐yl)acetato)pyridin‐2‐aminezinc(II) ( 2 ), (2‐((E )‐5‐fluoro‐2‐methyl‐1‐(4‐(methylsulfinyl)benzylidene)‐1H –inden‐3‐yl)acetato) pyridin‐2‐ylmethanaminezinc(II) (2‐((E )‐5‐fluoro‐2‐methyl‐1‐(4‐(methylsulfinyl)benzylidene)‐1H –inden‐3‐yl)acetate) ( 3 ), bis‐(2‐((E )‐5‐fluoro‐2‐methyl‐1‐(4‐(methylsulfinyl)benzylidene)‐1H –inden‐3‐yl)acetato)‐1,10‐phenanthrolinezinc(II) ( 4 ) and bis‐(2‐((E )‐5‐fluoro‐2‐methyl‐1‐(4‐(methylsulfinyl)benzylidene)‐1H –inden‐3‐yl)acetato)‐1,10‐phenanthrolinezinc(II) ( 5 ), have been prepared and fully characterized. In addition, the complexes were evaluated for their antibacterial activity using the in vitro agar diffusion method against two Gram‐positive (Staphylococcus epidermidis , Staphylococcus aureus ) and two Gram‐negative (Bordetella , Escherichia coli ) bacteria and yeast species (Saccharomyces and Candida ). Complex 5 showed reasonable activity against yeast. All compounds showed greater antibacterial activity against Gram‐positive than Gram‐negative bacteria. Results indicated that the efficiency of complex 5 in preventing the formation of β‐hematin was 67.6%. The efficiency of chloroquine as a standard drug was reported as 93%. Furthermore, the phosphatase activity of the Zn(II) complexes was studied and results indicated an effect of the zinc complexes on phosphatase activity. 相似文献
Synthesis of some new oxadiazole derivatives starting from 1,2,3-benzo[d]triazole-1-acetic hydrazide (1) is described. The target compounds 2-(N-substituted-aminocarbonylmethylthio)-5-(1,2,3-benzo[d]triazol-1-ylmethyl)- 1,3,4-oxadiazole (4a—4i) and 2-[2-(N-substituted-aminocarbonyl)ethylthio]-5-(1,2,3-benzo[d]triazol-1-ylmethyl)- 1,3,4-oxadiazole (5a—5i) were obtained in good yields via cyclisation of 1 and subjected to antibacterial activity test against pathogenic bacteria. The halogen containing mono- and di-substituted derivatives showed excellent antibacterial activity compared to other analogues. 相似文献
2‐amino‐3, 4, 5, or 6‐nitrobenzoic acids were reacted with PPh3(SCN)2 and alkyl isothiocyanates to give 5, 6, 7, or 8‐nitro‐2‐thioxo‐3‐substituted quinazolin‐4‐ones, respectively. The position of the nitro group was found to have significant influence on the outcome of the reactions. Similarly, the nature of the substituent at position 8 (NO2, NH2, NH(C═O)CH3) in 8‐substituted‐2‐methylthio quinazolin‐4‐ones was also found to significantly influence their reactivity towards morpholine. A selection of the products were also tested for in vitro antibacterial activity but little activity was observed. 相似文献
In an attempt to synthesize antibacterial agents effective against gram‐positive and gram‐negative bacteria, the efficient synthesis of novel bis‐azetidinones ( 3a–j ) has been established. Thus, cycloaddition reaction of substituted bis‐imines with chloroacetylchloride under microwave irradiation in the presence of zeolite yielded bis‐azetidinones ( 3a–j ). Structures of the synthesized compounds have been elucidated on the basis of their elemental analysis and spectral data (IR, 1H‐NMR, 13C‐NMR, and mass spectra). The synthesized bis‐azetidinones were screened for their antibacterial activity against five microorganisms: Bacillus subtilis, Proteus vulgaris, Staphylococcus aureus, Klebsiella pneumoniae, and Escherichia coli. They were found to exhibit good to moderate antibacterial activity. 相似文献
Indole‐3‐carboxylic acid hydrazide 3 was prepared and was treated with aromatic aldehydes in ethanol to give the corresponding hydrazone derivatives 4–7 in good yields. The indole carbohydrazide was incorporated into the 3‐indolyloxadiazoles 8–11 and 18 , 3‐indolyltriazoles 13–17 and 35 , 3‐indolylpyrazole derivatives 19–23 and carbamate derivatives 26–27 . Furthermore, interaction of the carboazide 24 with hydrazine hydrate in refluxing toluene afforded the corresponding semicarbazide derivative 30 . The thiadiazine derivative 34 was also prepared. Some of these compounds were screened in vitro for their antibacterial and antifungal activity. 相似文献
A tridentate Schiff base ligand, (E)‐3‐((2‐hydroxy‐3‐methoxybenzylidene)amino)‐2‐methylquinazolin‐4(3H)‐one [HL], and its mixed‐ligand Ni(II) complex [Ni(L)(imi)], were synthesized and fully characterized using elemental analysis, FT‐IR, UV–Vis and 1HNMR spectroscopy techniques. The structure of the synthesized ligand and complex was determined with single crystal X‐ray diffraction method. In the complex, a square planner geometry was observed around the Ni(II) central atom coordinated with the donor atoms of the Schiff base ligand and one nitrogen of imidazole group. In addition, the catalytic activity of the complex on the three‐component condensation of hydrazine hydrate with phthalic anhydride and dimedone to obtain 2H–indazolo[2,1‐b]phthalazine‐triones was investigated. Furthermore, in‐vitro antimicrobial studies were performed that indicated the great antibacterial activities of the Ni(II) complex against Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Bacillus cereus bacteria. 相似文献
A new 4‐hydroxy‐3‐carboxycoumarin ligand and its ruthenium(II) complexes ( 1 – 5 ) have been synthesized, characterized and screened for their in vitro antibacterial activity against a range of Gram‐positive and Gram‐negative bacteria. In addition, compounds 1 – 5 were investigated for antioxidant activities using superoxide radical, 2,2‐diphenyl‐1‐picrylhydrazyl radical and hydroxyl radical scavenging assays, in which most of them displayed significant antioxidant activities. Furthermore, compounds 1 – 5 were evaluated for anti‐inflammatory activity using indirect haemolytic and lipoxygenase inhibition assays and revealed good activity. The new complexes were characterized using spectroscopic methods in addition to elemental analysis. 相似文献
A modified electrode with bioaffinity to E. coli bacterial cells was used to detect bacteria presence on its surface and to produce an electrical signal triggering antibacterial drug release from another coupled electrode. The Sense‐and‐Treat system was realized in two different versions and suggested as the first step to future theranostic applications where bacteria presence results in automatic antibacterial treatment. 相似文献
A copolymer system of 2‐aminoethyl methacrylate and N‐isopropylacrylamide comprises novel properties: changes in conformation and hydrophilicity upon heating influence the antibacterial activity and result in a switchable biocidal effect. The copolymers are characterized via NMR, MALDI‐ToF MS, phase transition behavior, and antibacterial tests with E. coli or B. subtilis. MIC and MBC are determined using standard dilution methods, temperature‐dependence via incubation at different temperatures and cytotoxicity by MTT tests. The copolymers exhibit lower MIC in globule than coil conformation, crosslinking on cotton results in non‐leaching materials with better antibacterial activity above than below the phase‐transition point.
In view of developing novel bioactive compounds, a series of 2‐(5‐[2‐methyl‐6‐arylpyridin‐3‐yl]‐1,3,4‐oxadiazol‐2‐ylthio)‐1‐arylethanones (6a–n) were designed and synthesized in good yield. Novel compounds were evaluated for their antibacterial and anti‐inflammatory activities. All synthesized compounds were screened for their antibacterial activity against Staphylococcus aureus, Bascillus subtilis, Eschericia coli, and Pseudomonas aeruginosa strains. Compounds 6a , 6b , 6c , 6h , and 6i displayed the highest antibacterial activity with minimal inhibitory concentration (MIC) values ranging from 6.25–12.5 μg/mL in comparison with the standard Ciprofloxacin. The results of anti‐inflammatory activity of carrageenan‐induced footpad edema assay indicated that tested compounds exhibited remarkable anti‐inflammatory activity with percentage of inhibition of 63.9–70.1% (potency 96.8–106.20% of indomethacin activity) after 3 hr. Particularly, 6c – e and 6j – l were found to be excellent inhibitors of inflammation, with potential higher than that of the standard, Indomethacin. 相似文献
A successful aza‐Michael addition of arylamines to a conjugated enone, acryloylferrocene, has been achieved by ultrasonic irradiation of the mixture of these reactants and the catalyst, i.e., montmorillonite K‐10. This solvent‐free reaction, yielding ferrocene containing Mannich bases, 3‐(arylamino)‐1‐ferrocenylpropan‐1‐ones, considered as valuable precursors in organic synthesis, has been performed by using a simple ultrasonic cleaner. Among 17 synthesized β‐amino ketones, three were new ones, and these were fully characterized by spectroscopic means. X‐Ray crystallographic analysis of three of these crystalline products enabled the insight into the conformational details of these compounds. All compounds were evaluated for their antibacterial activities against six Gram‐positive and five Gram‐negative strains in a microdilution assay. The observed promising antibacterial activity (with a MIC value of 25 μg/ml (ca. 0.07 μmol/ml) as the best result for almost all tested compounds against Micrococcus flavus) seems not only to be compound but also bacterial species‐specific. 相似文献