Synthesis,Characterization, and Antimicrobial Properties of p-Chloroacetophenone Oxime-Based Furan Resins

A copolymer resin, p-chloroacetophenone oxime-furfuraldehyde (CAOFU), and a terpolymer resin, p-chloroacetophenone oxime-formaldehyde-benzoic acid (CAOFUBA), were synthesized in the presence of hydrochloric acid as catalyst. The structures of copolymer and terpolymer were established by FT-IR and ¹H NMR techniques. Molecular weight and polydispersity index were determined by gel permeation chromatography. The thermal stability was evaluated by thermogravimetric analyses (TGA). Softening temperatures (T_s) of these polymers were obtained from differential scanning calorimetry (DSC). All the synthesized polymers have shown reasonably good antimicrobial activities.     

Friedel-Crafts Polyetherketones: Synthesis, Characterization and Antimicrobial Properties

Low molecular weight Friedel-Crafts polyetherketones (PEK) were prepared from o-chloro anisole, 1,4-phenylenedioxy diacetychloride (1,4-PDC), chloroacetylchloride (CAC), 1,2-dichloroethane (DEC) and dichloromethane (DCM) using anhydrous AlCl₃ as catalyst and CS₂ as solvent. The polyetherketones were characterized by IR spectra and Gel permeation chromatography (GPC). The kinetic parameters for the thermal behaviour of the resins were obtained from thermo gravimetric analysis (TGA) using the Broido and Doyle method. Differential scanning calorimetry (DSC) traces were employed to obtain heat of fusion. All the polyetherketones were tested for their biological activity against bacteria, fungi and yeast. It was observed that most of the polyetherketones synthesized can be used as antibacterial and antifungal agents. This revised version was published online in July 2006 with corrections to the Cover Date.     

Oxo-Titanium(IV) Complex/Polymer Composites—Synthesis,Spectroscopic Characterization and Antimicrobial Activity Test

The emergence of a large number of bacterial strains resistant to many drugs or disinfectants currently used contributed to the search of new, more effective antimicrobial agents. In the presented paper, we assessed the microbiocidal activity of tri- and tetranuclear oxo-titanium(IV) complexes (TOCs), which were dispersed in the poly(methyl methacrylate) (PMMA) matrix. The TOCs were synthesized in reaction to Ti(OR)₄ (R = ⁱPr, ⁱBu) and HO₂CR’ (R’ = 4-PhNH₂ and 4-PhOH) in a 4:1 molar ratio at room temperature and in Ar atmosphere. The structure of isolated oxo-complexes was confirmed by IR and Raman spectroscopy and mass spectrometry. The antimicrobial activity of the produced composites (PMMA + TOCs) was estimated against Gram-positive (Staphylococcus aureus ATCC 6538 and S. aureus ATCC 25923) and Gram-negative (Escherichia coli ATCC 8739 and E. coli ATCC 25922) bacteria and yeasts of Candida albicans ATCC 10231. All produced composites showed biocidal activity against the bacteria. Composites containing {Ti₄O₂} cores and the {Ti₃O} core stabilized by the 4-hydroxybenzoic ligand showed also high activity against yeasts. The results of investigations carried out suggest that produced (PMMA + TOCs) composites, due to their microbiocidal activity, could find an application in the elimination of microbial contaminations in various fields of our lives.     

Synthesis,characterization, and antimicrobial activity of acrylic copolymers

2,4‐Dichlorophenyl methacrylate (2,4‐DMA) and vinyl acetate (VAc) were copolymerized with different feed ratios using dimethyl formamide (DMF) as a solvent and 2,2′‐azobisisobutyronitrile (AIBN) as an initiator at 70°C. The copolymers were characterized by infrared (IR) spectroscopy. Copolymer compositions were determined by ultraviolet (UV) spectroscopy. The monomer reactivity ratios were evaluated by the Fineman–Ross method. Average molecular weight and polydispersity index were determined by gel permeation chromatography (GPC), and the intrinsic viscosities of polymers were also discussed. Thermogravimetric analyses of polymers were carried out under a nitrogen atmosphere. The homo‐ and copolymers were tested for their antimicrobial activity against selected microorganisms. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 895–900, 2003     

4‐chloro‐3‐methylphenyl methacrylate copolymers with 2,4‐dichlorophenyl methacrylate: Synthesis,characterization, and antimicrobial activity

4‐Chloro‐3‐methylphenyl methacrylate (CMPM) and 2,4‐dichlorophenyl methacrylate (2,4‐DMA) were synthesized by reacting methacryloyl chloride with 4‐chloro‐3‐methylphenol (CMP) and 2,4‐dichlorophenol (2,4‐DP), respectively. Homo and copolymers of CMPM and 2,4‐DMA were obtained from different monomer feed ratios, using 2,2′‐azobisisobutyronitrile as initiator in toluene at 70°C. IR‐spectroscopy was employed to characterize the resulting homo and copolymers. Copolymer compositions were determined by ultraviolet (UV) spectroscopy. Fineman–Ross method was used to calculate the reactivity ratios of the monomers. Average molecular weight and polydispersity index were obtained by gel permeation chromatography (GPC). Thermogravimetric analyses (TGA) and differential thermal analysis (DTA) of copolymers were carried out under a nitrogen atmosphere. Antimicrobial effects of the homo and copolymers were also investigated for various microorganisms such as bacteria, fungi, and yeast. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100:439–448, 2006     

Biodegradable Polycaprolactone-Titania Nanocomposites: Preparation,Characterization and Antimicrobial Properties

Nanocomposites obtained from the incorporation of synthesized TiO₂ nanoparticles (≈10 nm average primary particle size) in different amounts, ranging from 0.5 to 5 wt.%, into a biodegradable polycaprolactone matrix are achieved via a straightforward and commercial melting processing. The resulting nanocomposites have been structurally and thermally characterized by transmission electron microscopy (TEM), wide/small angle X-ray diffraction (WAXS/SAXS, respectively) and differential scanning calorimetry (DSC). TEM evaluation provides evidence of an excellent nanometric dispersion of the oxide component in the polymeric matrix, with aggregates having an average size well below 100 nm. Presence of these TiO₂ nanoparticles induces a nucleant effect during polymer crystallization. Moreover, the antimicrobial activity of nanocomposites has been tested using both UV and visible light against Gram-negative Escherichia coli bacteria and Gram-positive Staphylococcus aureus. The bactericidal behavior has been explained through the analysis of the material optical properties, with a key role played by the creation of new electronic states within the polymer-based nanocomposites.     

Homopolymer of 4-chloro-3-methyl Phenyl Methacrylate and its Copolymers with Butyl Methacrylate: Synthesis, Characterization, Reactivity Ratios and Antimicrobial Activity

The methacrylate monomer 4-chloro-3‐methyl phenyl methacrylate (CMPM) was synthesized by reacting 4-chloro-3‐methyl phenol with methacryloyl chloride. The homopolymer and various copolymers of CMPM with n-butyl methacrylate were synthesized by free-radical polymerization in toluene at 70°C using 2,2′-azobis(isobutyronitrile) as the initiator. The CMPM monomer was characterized by Fourier transform IR and ¹H-NMR studies. The copolymers were characterized by IR spectroscopy. The molecular weights (M _n and M _w) and the polydispersity index were obtained from gel permeation chromatography. The solubility and intrinsic viscosity of the homopolymer and the copolymers are also discussed here. The copolymer composition obtained from UV spectra led to the determination of reactivity ratios employing Fineman-Ross and Kelen-Tudos linearization methods. Thermogravimetric analyses of the homopolymer and the copolymers were carried out under a nitrogen atmosphere. The homopolymer and the copolymers prepared were tested for their antimicrobial activity against bacteria, fungi and yeasts.     

Synthesis and Antimicrobial Activity of Boron-doped Titania Nano-materlals

Antibacterial activity of boron-doped TiO2 （B/TiO2） nano-materials under visible light irradiation and in the dark was investigated. A simple sol-gel method was used to synthesize TiO2 nano-materials. X-ray diffraction pattern of B/TiO2 nano-materials represents the diffraction peaks relating to the crystal planes of TiO2 （anatase and rutile）. X-ray photoelectron spectroscopy result shows that part of boron ions incorporates into TiO2 lattice to form a possible chemical environment like Ti-O-B and the rest exist in the form of B2O3. The study on antibacterial effect of B/TiO2 nano-materials on fungal Candida albicans （ATCC10231）, Gram-negative Escherichia coli （ATCC25922） and Gram-positive Staphylococcus aureus （ATCC6538） shows that the antibacterial action is more significant on Candida albicans than on Escherichia coli and Staphylococcus aureus. Under visible light irradiation, the antibacterial activity is superior to that in the dark.     

中氮茚并喹啉二酮衍生物的合成、表征及抗菌活性

以自制的6,7-二氯喹啉-5,8-二酮为原料,经一步反应合成了目标化合物9-氯-5,12-二酮-5,12-二氢中氮茚并[2,3-g]喹啉-6-甲酸乙酯,并通过1HNMR 、HRMS以及X-射线单晶衍射对其结构进行表征.活性测试结果表明,该化合物对革兰氏阳性菌具有选择性抑制作用,对耐甲氧西林金黄色葡萄球菌(MRSA)的最小抑菌浓度(MIC)为1μg/mL,优于阳性对照药物万古霉素.通过化合物与DNA促旋酶的分子对接实验进一步说明了化合物可能的作用机理.     

Synthesis,Surface and Antimicrobial Activity of Piperidine-Based Sulfobetaines

A new method for the preparation of new heterocyclic amine surfactants based on sulfobetaines is proposed. Interfacial activities of the surfactants obtained in aqueous solution were studied by surface tension measurements. The critical micelle concentration, surface excess concentration, minimum area per surfactant molecule, and standard Gibbs energy of adsorption were determined. The adsorption properties of these compounds depend significantly on the alkyl chain length. Alkyl chain length also affects biological properties of the new surfactants, determining the minimum inhibitory concentration and size of inhibited growth zone. The compounds have high antimicrobial activity.     

Synthesis,Thermal Behavior,and Antimicrobial Activity of Polyether Based on 4,7-dichloro 6-nitroquinazoline

The polyethers based on 4,7-dichloro 6-nitroquinazoline were synthesized and characterized by FT-IR and ¹H-NMR. The thermal properties and solubility were also performed with TGA, DSC, and viscometer. The molecular weight and degree of polymerization were determined with GPC. The method gave polyethers with inherent viscosities, good thermal stability, and solubility in solvent-like pyridine and DMF and also inhibited the growth of the microorganisms to a considerable extent.     

反丁烯二酸桂醇甲酯的合成及抗菌活性研究

以α,β-不饱和羰基结构为母体合成对皮肤无致敏性的反丁烯二酸桂醇甲酯(CMF)。合成实验表明:顺丁烯二酸酐与肉桂醇等摩尔混合,90℃反应2.5h后加入异构化催化剂在90℃反应4h转型,甲酯化反应以甲醇与桂醇单酯的摩尔比为6:1,在90℃恒温反应4h得率较高。抗菌活性实验表明:反丁烯二酸桂醇甲酯不但杀菌谱广,而且有效作用浓度低。在食品加工、保藏中具有广阔的开发应用前景。     

Synthesis and Antimicrobial Activity of Some Novel Cross-Linked Chitosan Hydrogels

Four novel hydrogels based on chitosan were synthesized via a cross-linking reaction of chitosan with different concentrations of oxalyl bis 4-(2,5-dioxo-2H-pyrrol- 1(5H)-yl)benzamide. Their structures were confirmed by fourier transform infrared X-ray (FTIR), scanning electron microscopy (SEM) and X-ray diffraction. The antimicrobial activities of the hydrogels against two crop-threatening pathogenic fungi namely: Aspergillus fumigatus (A. fumigatus, RCMBA 06002), and Aspergillus niger (A. niger, RCMBA 06106), and five bacterial species namely: Bacillis subtilis (B. subtilis, RCMBA 6005), Staphylococcus aureus (S. aureus, RCMBA 2004), Streptococcus pneumoniae (S. pneumonia, RCMB 000101) as Gram positive bacteria, and Salmonella typhimurium (S. typhimurium, RCMB 000104), and Escherichia coli (E. coli, RCMBA 5003) as Gram negative bacteria have been investigated. The prepared hydrogels showed much higher antimicrobial activities than that of the parent chitosan. The hydrogels were more potent in case of Gram-positive bacteria than Gram-negative bacteria. Increasing the degree of cross-linking in the hydrogels resulted in a weaker antimicrobial activity.     

N-苄叉丹皮酚腙的合成及其抗菌活性研究

以中药有效成分丹皮酚 (2-羟基-4-甲氧基苯乙酮)为原料,与水合肼反应得到中间体丹皮酚腙,然后分别与各种取代苯甲醛反应合成了9个N-苄叉丹皮酚腙,产率为50.5%~91.9%。初步探索了合成条件,目标化合物的结构经FT-IR,1H NMR,13C NMR, LC-MS表征。初步探索了合成条件、测定抗菌活性;结果表明：测定结果表明,部分化合物具有良好的抗菌活性,尤其是化合物N-(4-氟苄叉基)丹皮酚腙 (3c) 对金黄色葡萄球菌的MIC为4μg/mL,化合物N-(2-氟苄叉基)丹皮酚腙 (3b) 对大肠杆菌表现出与阳性对照药利福平相当的抗菌效果。     

N,N-二甲基十四烷基对乙烯基苄基氯化铵的合成及抑菌性能研究

以对乙烯基苄基氯和N,N-二甲基十四烷基叔胺(14DMA)为原料,合成了含有乙烯基的低毒高效的新型抗菌剂N,N-二甲基十四烷基对乙烯基苄基氯化铵。通过单因素实验确定优化的合成条件为:反应温度40～60℃、对乙烯基苄基氯与14DMA摩尔比1∶1.2、反应时间3h、20mL石油醚作溶剂、0.01g铜作催化剂,在此条件下产物收率达82.57%。产物的结构通过IR、1 HNMR确证。采用抑菌圈法研究了产物对金黄色葡萄球菌、枯草芽孢杆菌、大肠杆菌的抑菌活性,结果表明其抑菌效果良好。     

香草醛缩2，4-二硝基苯腙的合成和抑菌性研究

利用香草醛和2,4-二硝基苯肼的缩合反应合成香草醛缩2，4-二硝基苯腙，利用红外、紫外光谱和元素分析进行了结构表征。采用琼脂扩散法，以金黄色葡萄球菌、短小芽孢杆菌、大肠杆菌、沙门氏菌为生物指标，研究了香草醛缩2，4-二硝基苯腙对4种菌种的抑制作用，结果表明，在一定的浓度范围内，目标产物对所受试菌种具有一定的抑制作用。     

O-羧甲基壳聚糖抗菌性的研究

以金黄色葡萄球菌为实验菌种,研究了羧甲基化度对Ｏ－羧甲基壳聚糖抗菌性的影响,并与相应的壳聚糖的抗菌性对比,结果表明：Ｏ－羧甲基壳聚糖的抗菌性随着羧甲基化度的升高呈现出先升后降的规律,并且在比较宽的羧甲基化度范围内表现出较壳聚糖更好的抗菌性。     

Synthesis and Antimicrobial Activity of p-tetranitrocalix[4]arene Derivative

The present study demonstrates the synthesis and antimicrobial activity of the p-tetranitrocalix[4]arene (3). The microbial activity was determined against a variety of microorganisms, i.e., Gram-positive and Gram-negative bacterial strains such as Staphylococcus aureus ATCC 10231, Streptococcus viridans ATCC 12392, Escherichia coli ATCC 8739, as well as some fungal species including Aspergillus niger ATCC 16404, Aspergillus flavus ATCC 90906, and Candida albicans ATCC 32333. Kirby-Bauer well agar diffusion method was employed for the determination of antimicrobial activity. All the microorganisms were applied to a selective agar medium (Mueller Hinton Agar) for growth. It was observed that compound 3 is considerably effective against selected microorganisms. The MIC values were also evaluated. Thus, from the results it could be deduced that compound 3 may be a valuable addition to the therapeutic index.     

Sterically Hindered Quaternary Phosphonium Salts (QPSs): Antimicrobial Activity and Hemolytic and Cytotoxic Properties

Structure–activity relationships are important for the design of biocides and sanitizers. During the spread of resistant strains of pathogenic microbes, insights into the correlation between structure and activity become especially significant. The most commonly used biocides are nitrogen-containing compounds; the phosphorus-containing ones have been studied to a lesser extent. In the present study, a broad range of sterically hindered quaternary phosphonium salts (QPSs) based on tri-tert-butylphosphine was tested for their activity against Gram-positive (Staphylococcus aureus, Bacillus cereus, Enterococcus faecalis) and Gram-negative (Escherichia coli, Pseudomonas aeruginosa) bacteria and fungi (Candida albicans, Trichophyton mentagrophytes var. gypseum). The cation structure was confirmed to determine their biological activity. A number of QPSs not only exhibit high activity against both Gram-positive and -negative bacteria but also possess antifungal properties. Additionally, the hemolytic and cytotoxic properties of QPSs were determined using blood and a normal liver cell line, respectively. The results show that tri-tert-butyl(n-dodecyl)phosphonium and tri-tert-butyl(n-tridecyl)phosphonium bromides exhibit both low cytotoxicity against normal human cells and high antimicrobial activity against bacteria, including methicillin-resistant strains S. aureus (MRSA). The mechanism of QPS action on microbes is discussed. Due to their high selectivity for pathogens, sterically hindered QPSs could serve as effective tunable biocides.