Solubility Data of Diazepam in Binary and Ternary Mixtures of PEGs 200 and 400 with N-Methyl Pyrrolidone and Water at 298.2 K: Experimental Data and Modeling

Experimental solubilities of diazepam in binary and ternary solvents of polyethylene glycols 200 and 400 with N-methyl pyrrolidone and water at T = 298.2 K are reported. The Jouyban–Acree model was used to fit solubility data of diazepam in the binary and ternary solvent mixtures (106 data points) in which the overall mean relative deviations (OMRD %) is 13.1 % and the prediction OMRD % is 31.7 %. The combined version of the Jouyban–Acree model with Hansen solubility parameters was used for fitting and predicting the solubility data and the OMRDs % are 10.0 and 20.8 %, respectively. Also, the previously proposed trained versions of the Jouyban–Acree model were used for predicting the reported data in this work and all results are listed in the tables. The density of the solute-free solvent mixtures were measured and employed to calculate the constants of the Jouyban–Acree model and then the densities of the saturated solutions were predicted.     

An efficient palladium catalytic system for microwave assisted cyanation of aryl halides

Application of a new catalytic system for cyanation reaction of various aryl halides using K₄[Fe(CN)₆] as cyanating source was examined. The reactions were performed under microwave irradiation and results showed that application of this catalytic system and DMF at 130 °C minimized the reaction times from hours to minutes in good to excellent yields.     

Deprotection of Oximes,Phenylhydrazones, Semicarbazones and Thiosemicarbazones to the Corresponding Carbonyl Compounds Using Cetyltrimethylammonium Peroxodisulfate as a New and Selective Oxidizing Agent

Cetyltrimethylammonium peroxodisulfate (CTA)₂S₂O₈ was quantitatively prepared and used for the deprotection of oximes, phenylhydrazones, semicarbazones and thiosemicarbazones to the corresponding carbonyl compounds in acetonitrile. Its agent is more efficient and has advantages over similar reagents in terms of the amount of oxidant, short reaction time, simple work up, and high yield.     

Copper-catalyzed intramolecular alkene carboetherification: synthesis of fused-ring and bridged-ring tetrahydrofurans

Fused-ring and bridged-ring tetrahydrofuran scaffolds are found in a number of natural products and biologically active compounds. A new copper-catalyzed intramolecular carboetherification of alkenes for the synthesis of bicyclic tetrahydrofurans is reported herein. The reaction involves Cu-catalyzed intramolecular addition of alcohols to unactivated alkenes and subsequent aryl C-H functionalization provides the C-C bond. Mechanistic studies indicate a primary carbon radical intermediate is involved and radical addition to the aryl ring is the likely C-C bond-forming mechanism. Preliminary catalytic enantioselective reactions are promising (up to 75% ee) and provide evidence that copper is involved in the alkene addition step, likely through a cis-oxycupration mechanism. Catalytic enantioselective alkene carboetherification reactions are rare and future development of this new method into a highly enantioselective process is promising. During the course of the mechanistic studies a protocol for alkene hydroetherification was also developed.     

Kinetics of Thermal Decomposition and Kinetics of Substitution Reaction of Nano Uranyl Schiff Base Complexes

This study focuses on the synthesis, characterization, and kinetics of substitution reaction of new uranyl Schiff base complexes prepared in a crystalline state as well as in a form of nanoparticles with sizes ranging between 35 and 60 nm. Preliminary Fourier transform infrared spectroscopy (FTIR) and thermogravimetric (TG) measurements indicated no difference between the two forms. The compounds were characterized by UV–vis, ¹H NMR, cyclic voltammetry, X‐ray crystallography, FTIR, TG, and CHN analyses. X‐ray crystallography revealed coordination of the uranyl by the tetradentate Schiff base ligand and one solvent molecule, resulting in seven‐coordinated uranium. Cyclic voltammetry of the complexes in acetonitrile revealed the quasi‐reversible redox reaction. The TG and analysis of Coats–Redfern plots revealed that the kinetics of thermal decomposition of the complexes is of the first order in all stages. The study of the kinetics and the mechanism of the exchange reaction of the coordinated solvent with tributylphosphine was performed by the spectrophotometric method. The second‐order rate constants at four temperatures and the activation parameters revealed an associative mechanism for all corresponding complexes. Anticancer activity of the nano uranyl Schiff base complexes against cancer cell lines (Jurkat) was studied and determined by the MTT (3‐[4,5‐dimethylthiazol‐2‐yl]‐2,5‐diphenyl‐tetrazoliumbromide) assay.     

Understanding lipid recognition by protein-mimicking cyclic peptides

This paper describes our investigation of the structural determinants of a designed cyclic peptide (cLac, cyclic peptide mimicking lactadherin) (Zheng, H.; Wang, F.; Wang, Q.; Gao, J. J. Am. Chem. Soc.2011, 133, 15280–15283) for phosphatidylserine (PS) recognition. A highly efficient strategy that takes advantage of the native chemical ligation (NCL) chemistry has been developed for the synthesis and labeling of cyclic peptides in general. Ala scanning of the cLac peptide revealed a sophisticated model for PS binding, in which the peptide scaffold assembles multiple polar residues to balance the desolvation and electrostatic interactions (salt bridge and hydrogen bonding) to achieve lipid selectivity. The results suggest that cLac effectively mimics the membrane binding mechanism of the parent protein lactadherin.     

Numerical Simulation of Gas/Solid Heat Transfer in Metallic Foams: A General Correlation for Different Porosities and Pore Sizes

Transport in Porous Media - In the present research work, numerical simulations were performed to investigate the effects of structural parameters on fluid flow and heat transfer under unsteady...     

Electrochemical Sensor Based on Magnetic Fe3O4–Reduced Graphene Oxide Hybrid for Sensitive Detection of Binaphthol

Russian Journal of Electrochemistry - Naphthol is an environmental pollutant with highly toxic and corrosive. Naphthol can be absorbed by the body easily through the skin, and can cause serious...