Polysulfone/pyrene membranes: a new microwell assay platform for bioapplications

The use of PSU‐Py prepared by click chemistry as a platform in membrane‐bottom microwell plates for oxidase and hydrolase/oxidase‐based enzyme assays is studied. For the GOx assay, the postulated fluorescence mechanism is based on the consumption of glucose by dissolved oxygen and GOx in the microwell plates covered with the PSU‐Py membrane. For the AG‐GOx assay, maltose is used as AG substrate and hydrolyzed to glucose which is then oxidized by the GOx activity. It is shown that the PSU‐Py membrane acts as a fluorescence indicator of the enzymatic reactions, and both GOx and AG/GOx enzyme assays are successfully applied for glucose, maltose and acorbose analysis in the range 0.125–2.0 × 10^?3 M glucose, 0.05–0.5 × 10^?3 M maltose, and 0.0125–0.1 mg · mL^?1 acorbose, respectively.

     

A simple and sensitive LC-ESI-MS (ion trap) method for the determination of bupropion and its major metabolite, hydroxybupropion in rat plasma and brain microdialysates

A specific and highly sensitive liquid chromatography-electrospray mass spectrometry (LC-ESI-MS) method for the direct determination of bupropion (BUP) and its main metabolite hydroxybupropion (HBUP) in rat plasma and brain microdialysate has been developed and validated. The analysis was performed on a Bonus RP C18 (100 mm × 2.1 mm i.d., 3.5 μm particles) column using gradient elution with the mobile phase consisting of acetonitrile and ammonium formate buffer (10 mM, pH 4). Plasma samples were analyzed after a simple, one-step protein precipitation clean-up with trichloroacetic acid (TCA), however clean-up for microdialysis samples was not necessary, enabling direct injection of the samples into the LC-ESI-MS system. Signals of the compounds were monitored under the multiple reaction monitoring (MRM) mode of the LC-ESI-MS (ion trap) for quantification. The precursor to product ion transitions of m/z 240-184 and m/z 256-238 were used to measure BUP and HBUP, respectively. The method was validated in both plasma and microdialysate samples, and the obtained lower limit of quantification (LLOQ) was 1.5 ng mL⁻¹ for BUP and HBUP in both matrices. The intra- and inter-day assay variability was less than 15% for both analytes. This LC-ESI-MS method provided simple sampling, rapid clean-up and short analysis time (<9 min), applicable to the routine therapeutic monitoring and pharmacokinetic studies of BUP and HBUP.     

Design,synthesis, and characterization of some new benzimidazole derivatives and biological evaluation

A new series of benzimidazole derivatives ( 1-15 ) containing 1,2,4-triazole, 1,3,4-thiadiazole, 1,3,4-oxadiazole, and thiazolidinon rings have been synthesized. All new synthesized benzimidazole compounds were confirmed by ¹H NMR, ¹³C NMR spectra, and LC-MS, and they were examined for their antioxidant and antimicrobial activities. Compounds 7 and 1 showed the highest and the lowest antioxidant activities, respectively. The lowest minimum inhibition concentration value found in compound 5 against Enterobacter aerogenes.     

Polysiloxane‐containing benzoxazine moieties in the main chain

Polysiloxanes containing thermally curable benzoxazine units in the main chain have been synthesized. For this purpose, first the diallyl functional benzoxazine monomer is synthesized through the Mannich and respective ring closing reactions of 4,4′‐isopropylidenediphenol (bisphenol A), formaldehyde, and allyamine. Subsequent hydrosilylation reaction of the resulting allylic monomer (B‐ala) with 1,1,3,3‐tetramethyldisiloxane (TMDS) in the presence of Pt catalyst yields the corresponding oligo(B‐ala‐tetramethyldisiloxane)s (OBTMDS). Using the anionic polymerization route, OBTMDS was then converted to poly(bisbenzoxazinedimethylsiloxane)s (PBDMSs) by reacting with readily available cyclic oligomer octamethylcyclotetrasiloxane (D4) or decamethylcyclopentasiloxane (D5) in the presence of tetrabutylammonium hydroxide as catalyst. The structures of the precursor diallyl monomer, the intermediate oligomer, and the resulting polymers are confirmed by Fourier transform infrared and ¹H NMR analysis. Curing behavior of the products at various stages has also been studied by differential scanning calorimetry. Flexible transparent films of the PBDMSs are obtained by solvent casting. Thermal properties of the cured polymers are also investigated by thermogravimetric analysis. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010     

New route to ABCD-porphyrins via bilanes

A new strategy for preparing porphyrins that bear up to four different meso-substituents (ABCD-porphyrins) relies on two key reactions. One key reaction entails a directed synthesis of a 1-protected 19-acylbilane by acid-catalyzed condensation at high concentration (0.5 M) of a 1-acyldipyrromethane and a 9-protected dipyrromethane-1-carbinol (derived from a 9-protected 1-acyldipyrromethane). Three protecting groups (X) were examined, including thiocyanato, ethylthio, and bromo, of which bromo proved most effective. The bilanes were obtained in 72-80% yield, fully characterized, and examined by 15N NMR spectroscopy. The second key reaction entails a one-flask transformation of the 1-protected 19-acylbilane under basic, metal-templating conditions to give the corresponding metalloporphyrin. The reaction parameters investigated for cyclization of the bilane include solvent, metal salt, base, concentration, temperature, atmosphere, and time. The best conditions entailed the 1-bromo-19-acylbilane at 100 mM in toluene containing DBU (10 mol equiv) and MgBr2 (3 mol equiv) at 115 degrees C exposed to air for 2 h, which afforded the magnesium porphyrin in 65% yield. The magnesium porphyrin is readily demetalated to give the free base porphyrin. A stepwise procedure (which entailed treatment of the 1-(ethylthio)-19-acylbilane to oxidation, metal complexation, desulfurization, carbonyl reduction, and acid-catalyzed condensation) was developed but was much less efficient than the one-flask process. The new route to ABCD-porphyrins retains the desirable features of the existing "2 + 2" (dipyrromethane + dipyrromethane-1,9-dicarbinol) method, such as absence of scrambling, yet has significant advantages. The advantages include the absence of acid in the porphyrin-forming step, the use of a metal template for cyclization, the ability to carry out the reaction at high concentration, the lack of a quinone oxidant, avoidance of use of dichloromethane, and the increased yield of macrocycle formation to give the target ABCD-metalloporphyrin.     

高分子担载席夫碱及其Cr(Ⅲ)配合物:合成、表征、抗菌和抗真菌性能评价(英文)

用胺甲基树脂与5-氟-2-羟基苯甲醛,5-氟-3-氯-2-羟基苯甲醛,5-氟-3-甲基-2-羟基苯甲醛反应合成了3种新颖的高分子担载席夫碱和它们Cr(Ⅲ)配合物,并用元素分析、磁化率、IR、1H NMR、UV-Vis、TG/DTA对其进行了表征。就一些革兰氏阳性菌(芽孢杆菌属腊状芽孢杆菌(Bacillus cereus sp),单核细胞增生李斯特菌4b(Listeria monocytogenes 4b),藤黄微球菌(Micrococcus luteus),金黄色葡萄球菌(Staphylococcus aureus)表皮葡萄球菌(Staphylococcus epidermis))和革兰氏阴性菌(布鲁氏菌(Brucella abortus),大肠杆菌(Escherichia coli),恶臭假单胞菌SP(Pseudomonas putida sp.),痢疾志贺氏菌10(Shigella dysenteria type 10),伤寒杆菌H(Salmonella typhi H)和酵母菌(念珠菌)(yeast(Candida albicans))用井扩散法对高分子担载席夫碱和它们Cr(Ⅲ)配合物的生物学活性进行了筛选。     

Effect of Cycle Time on Polyhydroxybutyrate (PHB) Production in Aerobic Mixed Cultures

The aim of this study was to investigate the effect of cycle time on polyhydroxybutyrate (PHB) production under aerobic dynamic feeding system. The acetate-fed feast and famine sequencing batch reactor was used to enrich PHB accumulating microorganism. Sequencing batch reactor (SBR) was operated in four different cycle times (12, 8, 4, and 2 h) fed with a synthetic wastewater. The system performance was determined by monitoring total dissolved organic carbon, dissolved oxygen, oxidation-reduction potential, and PHB concentration. In this study, under steady-state conditions, the feast period of the SBR was found to allow the PHB storage while a certain part of stored PHB was used for continued growth in famine period. The percentage PHB storages by aerobic microorganism were at 16, 18, 42, and 55 % for the 12, 8, 4, and 2-h cycle times, respectively. The PHB storage was increased as the length of the cycle time was decreased, and the ratio of the feast compared to the total cycle length was increased from around 13 to 33 % for the12 and 2-h cycle times, respectively.     

Simple and efficient synthesis of N-alkyl and N-aryl succinimides in hot water

A new, simple synthesis of succinimides is described. The reactions were carried out under the ultimate green conditions excluding both catalyst and organic solvent by applying simple stirring at 100?°C. A wide variety of N-susbstituted succinimides have been prepared in high yields by using succinic acid and primary amines in hot water. Yield of N-alkyl substituted succinimides were found to be higher than those of N-aryl substituted succinimides.     

Phenol side‐groups‐containing fluorene polymer synthesized by catalytic oxidative polymerization

Catalytic oxidative polymerization (OP) of 4,4'‐(fluorene‐9,9‐di‐yl)diphenol (FDP), possessing both phenol and fluorene rings in its structure, was carried out in different organic solvents. Schiff base polymer‐copper (II) complex and hydrogen peroxide were used as a catalyst and an oxidizing agent, respectively. The structure of poly (4,4'‐(fluorene‐9,9‐di‐yl)diphenol) (PFDP) was confirmed by UV–vis, FT‐IR, NMR spectroscopies. Further characterization was conducted by means of thermogravimetric analysis (TGA), DSC, XRD, scanning electron microscopy (SEM), cyclic voltammetry (CV), and conductivity measurements. PFDP showed the optical band gap of 3.09 eV, the emission maximum at 335 nm, and the HOMO level of ?5.75 eV. Copyright © 2010 John Wiley & Sons, Ltd.     

Synthesis of some novel thiocyanotopurine derivatives and investigation of their antimicrobial activity and DNA interactions

A series of 6-thiocyanatopurine derivatives introduced with different alkyl groups in position 9 was synthesized. The structures of the synthesized compounds were evaluated via spectroscopic methods and elemental methods of analyses. All the synthesized compounds were screened for their antibacterial activities against Gram-positive and Gram-negative bacteria and for their antifungal activities against yeast strains. All the synthesized compounds showed better antibacterial activities against Gram-positive bacteria compared to Gram-negative bacteria. DNA interactions with pBR322 DNA were determined. Most of the compounds caused conformational changes in DNA.