The Phosporylation of Aniline Derivatives in Biphase Systems

Aniline derivatives were phosphorylated in biphase systems using three methods. A comparative study was performed. The best results were obtained when a solid–liquid system was used. This method is the easiest and lead to higher yields (54–81%).     

Methyl methacrylate as solvent for the thermal decomposition of the cyclic molecule pinacolone diperoxide: Toward the polymerization process

The decomposition rate constant (k_d) of pinacolone diperoxide (PDP, 3,6‐diterbutyl‐3,6‐dimethyl‐1,2,4,5‐tetraoxacyclohexane) in methyl methacrylate (MMA) is determined by the kinetic study of its thermal decomposition at temperatures from 110 °C to 140 °C. The calculated k_d values for PDP are higher than the corresponding values previously determined and reported for diethyl ketone triperoxide (DEKTP, 3,3,6,6,9,9‐hexaethyl‐1,2,4,5,7,8‐hexaoxacyclononane), for example, at 140 °C the k_d for PDP is 75.4 × 10^?5 s^?1, while for DEKTP, it is 50.6 × 10^?5 s^?1. The difference in the k_d between 130 °C and 140 °C indicates that the decomposition mechanism, sequential and/or concerted, is a function of temperature. The conformations of both initiators justify the higher k_d for PDP in MMA than DEKTP, where one single conformer is found for PDP, whereas 212 conformers are found for DEKTP. Bulk polymerization of MMA using PDP as the initiator reveals also the presence of an induction period, such as in DEKTP case. This work provides mechanistic insights into the interactions among the bifunctional cyclic peroxide PDP and the MMA monomer and their influence on the polymerization kinetics. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019 , 57, 997–1007     

Preparation,physicochemical characterization and biological activity evaluation of some inclusion complexes containing artesunate

Journal of Thermal Analysis and Calorimetry - The use of cyclodextrins as carrier molecules is currently highly researched since they can improve not only the apparent water solubility and...     

Synthesis,characterization, and toxicity of hollow gold nanoshells

Hollow gold nanoshells (HGN) with a diameter of 50–70 nm and tunable optical properties within the near-infrared region were synthesized from a substitution reaction using a sacrificial template, in which the morphological properties of the HGN were affected by the synthesis conditions. Using EDX line scan, the composition of the structure was determined to verify if the sacrificial template is completely consumed or residues remain after the chemical synthesis, obtaining that the final HGN structure contains about 11% of the remaining silver that showed no significant effect on the cell viability of a hNS1 cell line, but resulted as toxic on a C6 glioma cell line at high concentrations. The photothermal properties were evaluated using a NIR laser, which despite its low power showed the conversion of light into heat. This study was conducted to evaluate the potential of these nanostructures as therapeutic agents with an emphasis on toxicity.     

Simultaneous Determination of Some Analgesic Drugs Using Mixed Mode Stationary Phase

A new HPLC method based on a mixed mode stationary phase Hypersil Duet C18/SAX was developed and applied for the simultaneous determination of acetaminophen, acetylsalicylic acid and codeine. Parameters, such as the composition of the mobile phase, the nature of the organic modifier, the buffer type and the flow rate were investigated to optimize the separation. The results obtained show that the new HPLC method is rapid, highly efficient and selective. The studied compounds are separated in 10 min, by means of a mobile phase containing phosphate buffer (pH 7.50) and methanol (65:35 v v⁻¹). The retention mechanisms of each analyte were investigated using both the linear solvent strength theory and stoichiometric displacement model. The method was fully validated and showed good linearity for each compound for a concentration ranging between 2.0 and 40 μg mL⁻¹. The limits of detection and quantification were determined and they are lower than 0.1 μg mL⁻¹. The precision (RSD) of the method does not exceed 2 % for all studied compounds. The method was successfully applied for the assay of acetaminophen, acetylsalicylic acid and codeine in pharmaceutical formulations.

     

Effective Purification of Cerrena unicolor Laccase Using Microfiltration, Ultrafiltration and Acetone Precipitation

Microfiltration followed by concentration and diafiltration on ultrafiltration membranes (Biomax-100, Biomax-10 and Ultracel-10) was used to recover extracellular laccase (EC 1.10.3.2) from culture broth of wood-rotting fungus Cerrena unicolor. Feed, permeate, retentate and membrane wash-out solutions were analysed for the presence of laccase, proteases, protein and brown impurities. An easy, cheap and short-term procedure was proposed to obtain retentates with low yields of total proteins (less than 14%), proteases activity (less than 15%) and brown impurities (from 2% to 29%) with a simultaneous laccase recovery above 73%. The degree of laccase purification varied from 6.7 to 11.0 and depended on the type of membrane used and content of brown pigments in the feed. Subsequent protein precipitation with cold acetone increased the degree of purification about twice and reduced proteases and brown impurities to some extent. Ultracel-10 membrane was recommended as the best solution to prevent fouling of membranes and to obtain laccase-enriched fraction with a very low content of proteases and brown pigments.