Choline chloride/CuCl as an effective homogeneous catalyst for palladium-free Sonogashira cross-coupling reactions

Choline chloride–CuCl (ChCl–CuCl) has been employed as an efficient catalytic system in the palladium-free Sonogashira-type cross-coupling reactions of phenylacetylene with a variety of aryl halides. Choline chloride, as an effective ligand and a quaternary ammonium salt, demonstrated an efficient stabilizing effect on the Cu(I) species during the reaction. This homogeneous catalytic system is attractive in view of its ease of application and low cost.     

Trichloroacetonitrile–hydrogen peroxide: a simple and efficient system for the selective oxidation of tertiary and secondary amines

A variety of tertiary and secondary amines were efficiently oxidized to their corresponding N-oxides and nitrones, respectively, using the trichloroacetonitrile–hydrogen peroxide system. The in situ generated trichloromethylperoxyimidic acid is the active reagent for the oxidation processes.     

pH-sensitive supramolecular copolydendrimers,new anticancer drug delivery system

In this work, new class of supramolecular copolydendrimers (SCDs) consisting of polyamidoamines (PAMAMs) and polyglycerol were synthesized through host-guest interactions. SCDs were able to encapsulate, transport, and release doxorubicin (DOX) efficiently. Host-guest interactions between PAMAM and polyglycerol was depended on pH so that aqueous solutions of SCDs and SCDs-based drug delivery systems were stable at room temperature and pH?=?7.4, but their building blocks were separated in lower pHs(     

One-pot three-component synthesis of 1,4-disubstituted 1H-1,2,3-triazoles using green and recyclable cross-linked poly(4-vinylpyridine)-supported copper sulfate/sodium ascorbate in water/t-BuOH system

Cross-linked poly(4-vinylpyridine)-supported copper sulfate, [P₄-VP]CuSO4 as a green and recyclable, heterogeneous catalyst in the presence of sodium ascorbate (NaAsc), is reported for the regioselective synthesis of 1,4-disubstituted-1,2,3-triazoles from benzyl halides, sodium azide and terminal alkyne in water/t-BuOH (1/1:V/V) at 70 °C. Various alkyl halides and benzyl halides, with electron-withdrawing groups as well as electron-donating groups, were used for synthesis of various 1,4-disubstituted-1,2,3-triazoles in high yields. The present procedure offers as short reaction time and simple reaction work up. This catalyst can be recovered by simple filtration and recycled several consecutive runs without any loss of its efficiency.     

Three‐component One‐pot Synthetic Route to Functionalized N‐Phenyl‐ and N,N‐(1,4‐phenylene)‐2‐alkylimino‐2,3‐dihydrothiazoles under Mild,Solvent‐ and Catalyst‐free Conditions

A simple and efficient one‐pot synthesis of alkyl‐2‐(alkylimino)‐4‐methyl‐3‐phenyl‐2,3‐dihydrothiazole‐5‐carboxylate and dialkyl 3,3′‐(1,4‐phenylene)‐bis‐[2‐(alkylimino)‐4‐methyl‐2,3‐dihydrothiazole‐5‐carboxylate] derivatives from the reaction of phenylisothiocyanate (and also 1,4‐phenylene diisothiocyanate) and primary alkylamines in the presence of 2‐chloro‐1,3‐dicarbonyl compounds is described. This new protocol has several advantages such as lack of necessity of the catalyst and solvent, good yields,mild conditions and short times for reaction.     

Triiodide PVC Membrane Electrode Based on a Charge‐Transfer Complex of Iodine with Ditertbutyl‐Dicyclohexyl‐18‐Crown‐6

A new triiodide ion‐selective electrode based on a charge‐transfer complex of iodine with ditertbutyl‐dicyclohexyl‐18‐crown‐6 (t‐Bu)₂DC18C6 as membrane carrier was prepared. The electrode has a linear dynamic range from 6.3 × 10^?3‐5 × 10^?6 with a Nernstian response of 58.6 ± 1 mV decade^?1 and a detection limit of 1.3 × 10^?6 M. The response time of the sensor was 25 s. The membrane could be used for two months without any divergence in potentials. The electrode exhibits an anti‐Hofmeistetr selectivity sequence with a preference for triiodide at pH 2.0‐10.0. The response mechanism of the electrode was investigated by Uv‐Vis spectroscopic technique. The electrode can be used for the determination of ascorbic acid in orange juice.     

Naproxen-eudragit RS100 nanoparticles: preparation and physicochemical characterization

The objective of the present study was to formulate naproxen-eudragit RS100 nanoparticles and investigate the physicochemical characteristics of the prepared nanoparticles. The nanoparticles of naproxen with eudragit RS100 were formulated using the solvent evaporation/extraction technique (the single emulsion technique). The effect of several process parameters, i.e., drug/polymer ratio, aqueous phase volume and speed of homogenization were considered on the size of the nanoformulations. The physicochemical characteristics of nanoparticles were studied applying particle size analysis, differential scanning calorimetry, X-ray crystallography, Fourier transform infrared spectroscopy and scanning electron microscopy. The release rate of naproxen from various drug/polymer nanoparticles was investigated as well. All the prepared formulations using eudragit RS100 resulted in nano-range size particles with relative spherical smooth morphology. The nanoparticles of naproxen-eudragit RS100 displayed lower crystallinity. The intermolecular interaction between naproxen and eudragit RS100 was detected in the FT-IR spectrum of the nanoparticles. All the nanoparticles displayed a slowed release pattern with the reduced burst release in comparison with the intact drug powder and physical mixtures of drug and polymer. According of these findings, formulation of the naproxen-eudragit RS100 nanoparticles was able to improve the physicochemical characteristics of the drug and possibly will increase the anti-inflammatory effects of drug following its ocular or intra-joint administration.     

One‐Pot,Four‐Component Synthesis of Fully Substituted 1,3,4‐Oxadiazole Derivatives from (Isocyanoimino)triphenylphosphorane,a Primary Amine,an Aromatic Carboxylic Acid,and Chloroacetone

The 1 : 1 imine intermediate 7 generated by the addition of a primary amine 2 to chloroacetone ( 1 ) is trapped by (isocyanoimino)triphenylphosphorane ( 4 ) in the presence of an aromatic carboxylic acid 3 and leads to the formation of the corresponding iminophosphorane intermediate 9 (Scheme 2). The 1,3,4‐oxadiazole derivatives 5 are then formed via an intramolecular aza‐Wittig reaction of the iminophosphorane intermediate 9 . The reactions were completed under neutral conditions at room temperature. The fully substituted 1,3,4‐oxadiazole derivatives 5 were produced in high yields (Table).     

Electrodeposited acetaminophen as a bifunctional electrocatalyst for simultaneous determination of ascorbic acid, glutathione, adrenaline and tryptophan

In this study, an acetaminophen-modified glassy carbon electrode (ACMGCE) was fabricated for the purpose of investigating its electrochemical behavior by cyclic voltammetry (CV). ACMGCE serves as an excellent bifunctional electrocatalyst for the oxidation of ascorbic acid (AA) and glutathione (GSH) in a phosphate buffer solution (pH 7.0). The kinetic parameters such as the electron transfer coefficient, α, and the heterogeneous electron transfer rate constant, k', for the oxidation of AA and GSH at the ACMGCE surface were determined by CV. In addition, detection limits of 3.89 μM for AA and 0.37 μM for GSH were obtained at the ACMGCE using a differential pulse voltammetric (DPV) method. In DPV, the bifunctional modified electrode could separate the oxidation peak potentials of AA, GSH, adrenaline (AD) and tryptophan (Trp) present in the same solution, though the peak potentials were indistinguishable at a bare GCE. Finally, the modified electrode was successfully applied to the determination of AA in a pharmaceutical preparation and GSH in a human plasma sample.     

Synthesis and characterization of NiO nanoclusters via thermal decomposition

Thermal decomposition process has been developed to synthesize nickel oxide (NiO) nanoclusters via the reaction between a new precursor, nickel oxalate [Ni(O₄C₂)(H₂O)₄] and oleylamine (C₁₈H₃₇N). The combination of triphenylphosphine (C₁₈H₁₅P) and C₁₈H₃₇N were added as surfactants to control the particle size. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectroscopy, thermogravimetric analysis (TGA) and ultraviolet–visible (UV–Vis) spectroscopy. The synthesized NiO nanoclusters have a cubic structure with average size 2–10 nm.