Biologically active polymers. V. Synthesis and antimicrobial activity of modified poly(glycidyl methacrylate‐co‐2‐hydroxyethyl methacrylate) derivatives with quaternary ammonium and phosphonium salts

Antimicrobial copolymers bearing quaternary ammonium and phosphonium salts based on a copolymer of glycidyl methacrylate and 2‐hydroxyethyl methacrylate were synthesized. Poly(glycidyl methacrylate‐co‐2‐hydroxyethyl methacrylate) was modified for the introduction of chloromethyl groups by its reaction with chloroacetyl chloride. The chloroacetylated copolymer was modified for the production of quaternary ammonium or phosphonium salts. The antimicrobial activity of the obtained copolymers was studied against gram‐negative bacteria (Escherichia coli, Pseudomonas aeruginosa, Shigella sp., and Salmonella typhae), gram‐positive bacteria (Bacillus subtilus and B. cereus), and the fungus Trichophyton rubrum by the cut‐plug method. The results showed that the three copolymers had high antimicrobial activity. A control experiment was carried out on the main polymer without ammonium or phosphonium groups. The copolymer bearing quaternary salt made from tributyl phosphine was the most effective copolymer against both gram‐negative and gram‐positive bacteria and the fungus T. rubrum. The diameters of the inhibition zones ranged between 20 and 60 mm after 24 h. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 2384–2393, 2002     

Biologically Active Polymers, 6

Various copolymers were prepared by the copolymerization of 2‐chloroethyl vinyl ether (CEVE) with methyl methacrylate (MMA), hydroxyethyl methacrylate (HEMA) and vinylbenzyl chloride (VBC). The copolymers were further modified by quaternization with triethylamine, triphenylphosphine, and tributylphosphine. The antimicrobial activities of the prepared, quaternized copolymers were evaluated against Candida albicans, Fusarium oxysporium, Aspergillus flavus, Bacillus subtilis, Escherichia coli, and Staphylococcus aureus. The antimicrobial activity was explored by the cut plug method, viable cell counting (surviving ratio), transmission electron microscopy, and potassium leakage tests. The results indicated that the prepared polymers had a high antimicrobial activity, and control experiments on the main polymer without ammonium, phenyl, or butyl and/or phosphonium groups were carried out. The phosphonium containing polycationic biocides are more effective than the quaternary ammonium salt polymers. Examining the C. albicans and S. aureus polymer‐treated cells by electron microscopy indicated disruption for the cytoplasmic membrane and release of potassium ion as shown by the assay of potassium leakage.

Growth inhibition of different concentrations of polymer (X_b).     

Enhancement of the phosphorescence of organic luminophores upon interaction with a mercury trifunctional Lewis acid

The interaction of the trinuclear mercury(II) complex [(o-C(6)F(4)Hg)(3)] (1) and pyrene leads to the formation of the 1:1 adduct 1.pyrene. The crystal structure of this adduct reveals the existence of supramolecular stacks in which molecules of 1 and molecules of pyrene alternate along the infinite chains. Steady-state and time-resolved photoluminescence measurements indicate the occurrence of a heavy atom effect which results in red, green, and blue (RGB) phosphorescent emissions for 1.pyrene, 1.naphthalene, and 1.biphenyl, respectively.     

Indeno[1,2-b]pyridin-5-one derivatives containing azo groups and their hydrazonal precursors: Synthesis,antimicrobial profile,DNA gyrase binding affinity,and molecular docking

The prevalence of germs that are resistant to many antibiotics is rising rapidly the world over. There is a large group of researchers actively looking for better medicines. Here, we designed two series of hydrazonal and indeno[1,2-b]pyridin-5-one bearing hydrazone and azo-groups to test their antimicrobial activity. Molecular structures of all derivatives were assured based on their spectral data and elemental analyses. Results of the antimicrobial activity of the tested hydrazone and azo compounds showed promising potential for several derivatives. The minimum inhibitory concentrations (MICs) of hydrazones 4a - h and 6a - g displayed good antibacterial reactivities with a range of 3.91–250 μg/mL and moderate antifungal activity with a range of 15.6–500 μg/mL. The most promising hydrazone 4f and azo- 6a compounds demonstrated MIC values against Streptococcus faecalis and Escherichia coli equal to 3.91 and 7.81 μg/mL, respectively. Moreover, azo compound 6a showed MIC value equal to 3.91 μg/mL against Enterobacter cloacae species. Additionally, derivative 4f exhibited a significant inhibitory profile against the E. coli gyrase A enzyme (IC₅₀ = 5.53 μg/mL). On the other hand, compound 6a (IC₅₀ 14.05 μg/mL) exhibited the lowest DNA gyrase inhibitory activity as compared to compounds 4f and reference standard drug novobiocin, IC₅₀ 5.53 and 1.88 μg/mL, respectively. Pharmacokinetic and pharmacodynamic profiles and molecular docking studies for the two most promising molecules 4f and 6a were computed and revealed that both compounds have good ADME profiles and high binding affinity to DNA gyrase binding site.     

High CO2 uptake and selectivity by triptycene-derived benzimidazole-linked polymers

Successful incorporation of triptycene into benzimidazole-linked polymers leads to the highest CO(2) uptake (5.12 mmol g(-1), 273 K and 1 bar) by porous organic polymers and results in high CO(2)/N(2) (63) and CO(2)/CH(4) (8.4) selectivities.     

Nickel-catalyzed synthesis of nanoporous organic frameworks and their potential use in gas storage applications

The synthesis of highly nanoporous organic frameworks (NPOFs) has been established using nickel(0)-catalyzed Yamamoto coupling reactions, which has afforded highly porous polymers featuring remarkable chemical and thermal stability. Treatment of 1,3,5-tris(4-bromophenyl)benzene, 1,2,4,5-tetrakis(4-bromophenyl)benzene, or 1,3,5,7-tetrakis(4-iodophenyl)adamantane with Ni(cod)₂ in DMF at 80°C for 48 h afforded the nanoporous organic frameworks, NPOF-1, NPOF-2, and NPOF-3, respectively, as white powders in quantitative yields. All NPOFs are insoluble in common organic solvents such as dimethylformamide, tetrahydrofuran, toluene, dichloromethane, and methanol. The chemical composition and structural aspects of NPOFs were investigated by spectral and analytical methods while porosity was examined by nitrogen porosity measurements. In spite of their amorphous nature, NPOFs exhibit permanent porosity and high Langmuir surface areas (NPOF-1: 2,635 m² g^?1; NPOF-2: 4,227 m² g^?1; NPOF-3: 2,423 m² g^?1), which make them attractive for subsequent use in gas storage and separation applications, among others. The performance of NPOFs in hydrogen storage was evaluated at 1 bar and 77 K and revealed that these highly porous architectures can store up to 1.45 wt% of hydrogen.     

Antibacterial and wound healing properties of cellulose acetate electrospun nanofibers loaded with bioactive glass nanoparticles; in-vivo study

Bioactive glasses (BGs) have gained great attention owing to their versatile biological properties. Combining BG nanoparticles (BGNPs) with polymeric nanofibers produced nanocomposites of great performance in various biomedical applications especially in regenerative medicine. In this study, a novel nanocomposite nanofibrous system was developed and optimized from cellulose acetate (CA) electrospun nanofibers containing different concentrations of BGNPs. Morphology, IR and elemental analysis of the prepared electrospun nanofibers were determined using SEM, FT-IR and EDX respectively. Electrical conductivity and viscosity were also studied. Antibacterial properties were then investigated using agar well diffusion method. Moreover, biological wound healing capabilities for the prepared nanofiber dressing were assessed using in-vivo diabetic rat model with induced wounds. The fully characterized CA electrospun uniform nanofiber (100–200 nm) with incorporated BGNPs exhibited broad range of antimicrobial activity against gram negative and positive bacteria. The BGNP loaded CA nanofiber accelerated wound closure efficiently by the 10th day. The remaining wound areas for treated rats were 95.7?±?1.8, 36.4?±?3.2, 6.3?±?1.5 and 0.8?±?0.9 on 1st, 5th, 10th and 15th days respectively. Therefore, the newly prepared BGNP CA nanocomposite nanofiber could be used as a promising antibacterial and wound healing dressing for rapid and efficient recovery.

     

Synthesis of novel macrocyclic di‐ and tetralactams containing triazole subunits

The new macrocyclic di‐ and tetralactams 9 , 15 , and 16 were obtained in 16–24% yields by heating the appropriate bis‐amines 7 or 8 with the corresponding bisaldehyde 5 or 14 in refluxing acetic acid under high‐dilution conditions. © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:551–559, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10191