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 hydration analysis of Ba2+-, Cu2+- or Bi3+-doped CaO–Al2O3–ZrO2-based cements

Journal of Thermal Analysis and Calorimetry - This paper deals with the design, synthesis, hydration mechanism and hydration products of novel Ba2+-, Cu2+- or Bi3+-doped...     

Oxathiaphospholane Approach to the Synthesis of Conjugates of Amino Acids Methyl Esters with Nucleosides

Based upon 1,3,2-oxathiaphospholane chemistry, 5'-O-derivatization of nucleosides with the O-methyl esters of amino acids was performed and corresponding conjugates were obtained in satisfactory yield.     

Easy and efficient deracemization of all trans-1,3-diphenyl-2,4-bis-[α-hydroxybenzyl]-cyclobutane and its bisphenylsulfanyl derivative and the assignment of the absolute configuration

An effective deracemization of all trans-1,3-diphenyl-2,4-bis-[α-hydroxybenzyl]-cyclobutane 1 was achieved by the application of the (R)-(?)-O-acylmandelic acid as a resolving agent, followed by the crystallization of the diastereomeric esters. The kinetic resolution was also observed in the esterification. Racemic 1 was transformed into bisphenylsulfanyl derivative 3. Enantioselective oxidation of 3 with a VO(acac)₂-chiral Schiff Base catalytic system led to a kinetic resolution, and highly enantiomerically enriched bissulfides/bissulfoxides were isolated. Assignment of the absolute configuration was made by spectroscopic methods and chemical correlation. Due to the rigid C₂-symmetric framework, chiral compounds 1 and 3 have strong steric requirements and may be useful in chiral recognition.     

AgI-Ag2O-V2O5 glasses as ion-to-electron transducers for the construction of all-solid-state microelectrodes

A method for the fabrication of ion-selective all-solid-state microelectrodes is presented. The ion-to-electron transduction process takes place into the transducer material. In this approach, AgI-Ag₂O-V₂O₅ glasses, which exhibit ionic and electrical conductivity are applied as ion-to-electron transducers of polymeric membrane microelectrodes. All-solid-state electrodes based on potassium-sensitive poly(vinyl chloride) membranes, deposited directly on the surface of glass composites, exhibited theoretical responses. Their selectivity and durability were comparable to planar microelectrodes containing an internal electrolyte immobilized in the intermediate hydrogel layer. The only disadvantage of the proposed structures was their limited reproducibility. Moreover, it was found that the unmodified AgI-Ag₂O-V₂O₅ glasses can be applied as ion-sensitive membrane of solid-state microelectrodes for the determination of Ag⁺ and I⁻ ions.     

Weighted reproducing kernels and Toeplitz operators on harmonic Bergman spaces on the real ball

For the standard weighted Bergman spaces on the complex unit ball, the Berezin transform of a bounded continuous function tends to this function pointwise as the weight parameter tends to infinity. We show that this remains valid also in the context of harmonic Bergman spaces on the real unit ball of any dimension. This generalizes the recent result of C. Liu for the unit disc, as well as the original assertion concerning the holomorphic case. Along the way, we also obtain a formula for the corresponding weighted harmonic Bergman kernels.

     

Fluorescent Turn-On Probes for the Development of Binding and Hydrolytic Activity Assays for mRNA Cap-Recognizing Proteins

The m⁷G cap is a unique nucleotide structure at the 5′-end of all eukaryotic mRNAs. The cap specifically interacts with numerous cellular proteins and participates in biological processes that are essential for cell growth and function. To provide small molecular probes to study important cap-recognizing proteins, we synthesized m⁷G nucleotides labeled with fluorescent tags via the terminal phosph(on)ate group and studied how their emission properties changed upon protein binding or enzymatic cleavage. Only the pyrene-labeled compounds behaved as sensitive turn-on probes. A pyrene-labeled m⁷GTP analogue showed up to eightfold enhanced fluorescence emission upon binding to eukaryotic translation initiation factor 4E (eIF4E) and over 30-fold enhancement upon cleavage by decapping scavenger (DcpS) enzyme. These observations served as the basis for developing binding- and hydrolytic-activity assays. The assay utility was validated with previously characterized libraries of eIF4E ligands and DcpS inhibitors. The DcpS assay was also applied to study hydrolytic activity and inhibition of endogenous enzyme in cytoplasmic extracts from HeLa and HEK cells.     

Practical Phase-Transfer Synthesis of N-(Ethoxycarbonyl)Phthalimide and Its Analogues

Potassium imides are N-acylated with ethyl chloroformate in the presence of tetrabutylammonium chloride to form the corresponding N-etyhoxycarbonyl derivatives, useful agents for N-protection of primary amines.