Chemically modified screen-printed electrodes as efficient potentiometric sensors for cyclobenzaprine hydrochloride determination in pure and pharmaceutical preparations

Chemically modified screen-printed electrodes (SPEs) with 3,4-dihydroxy-9,10-dioxo-2-anthracenesulfonic acid sodium salt [Alizarin Red (ALZ.R)] and tricresylphosphate (TCP) were fabricated and examined for potentiometric determination of cyclobenzaprine hydrochloride (CZP.HCl) in pure and pharmaceutical samples. The content of ALZ.R in the prepared SPEs varied, which significantly affected their potentiometric response during CZP.HCl estimation. The measured potential value was dependent on the pH of the studied solution. A stable modified SPE sensor was prepared with reproducible readings within 22 days. A wide linear concentration range could be measured with Nernestian slope value of 60.12 ± 0.18 mV decade⁻¹. Based on the recorded analytical parameters of these modified SPEs, a sensitive and reliable detection of CZP.HCl in pharmaceutical samples could be attained.     

Utilization of 2-ylidene-4-thiazolidinones in the synthesis of heterocyclic compounds. Part I: Synthesis of pyrazoles

2-Ylidene and 2,5-diylidene-4-thiazolidinones 2a–d were synthesized and converted into pyrazole derivatives 4a–d by reaction with hydrazine hydrate. A mechanism of this novel conversion is suggested.     

Amberlyst-15 and Amberlite-200C: Efficient catalysts for aldol and cross-aldol condensation under ultrasound irradiation

This paper presents an improved synthesis of trans-chalcones and α,α′-bis(arylmethylidene) cycloalkanones under ultrasound irradiation in the presence of commercial acid-resins as catalysts in solvent free conditions. Several trans-chalcones and α,α′-bis(arylmethylidene) cycloalkanones were synthesized in good yields and excellent selectivity in a short reaction time.     

Novel metal complexes of 3-acetylcoumarin-2-hydrazinobenzothiazole Schiff base: Design,structural characterizations,DNA binding,DFT calculations,molecular docking and biological studies

Five new Cu (II), Zn (II), Pd (II), Ru (III) and Ag(I) complexes, derived from the 3-acetylcoumarin-2-hydrazinobenzothiazole Schiff base (Hachbt), have been synthesized and characterized. The structures were established with the aid of elemental analyses (C, H, N), FT-IR, ¹H-NMR, ESR, UV–visible and ESI-mass spectra. The complexes were also investigated by magnetic susceptibility, thermal gravimetric analysis (TG-DTA) and cyclic voltammetry measurements. The results suggest that the Schiff base ligand behaves in two different ways: neutral mono/bidentate or mono-negative bi/tridentate. The calf thymus DNA (CT DNA) binding affinities of Hachbt and its complexes have been examined by UV–visible spectroscopy. The antifungal activity of the compounds was also screened against two fungal species of wood-decay basidiomycetes using the agar dilution method. Different complexes caused a reduction in the fungal colony diameters at a media concentration of 100 μg/ml. The best antifungal activity was observed for the Pd (II) and Ag(I) complexes with a 60% and 79% reduction, respectively. The effect of the complexes on the ability of the same fungi to decolorize poly-R dye on agar plates was also tested. All of the complexes showed an enhanced effect on the decolorization ability and the Cu (II) and Ru (III) complexes exhibited the strongest effect at a media concentration of 5 μg/ml. Theoretical studies were performed for all the complexes using the DFT/B3LYP/6–31 + g(d) basis set for calculations on the ligand atoms and LAN2DZ for the Pd (II) complex. The optimized geometries were found to be in a good agreement with the proposed structures. The molecular docking calculations show that the binding affinity of the Pd (II) complex is −309.170-309.2 kcal/mol, which suggests complexation with the DNA minor groove.     

Synthesis,characterization and anticancer studies of ferrocenyl complexes containing thiazole moiety

A ferrocenyl ligand was prepared from condensation of l,l′‐diacetylferrocene with 2‐amino‐5‐methylthiazole, to give the ligand. This ligand forms 1:1 complexes with lead(II), cobalt(II), nickel(II), copper(II) and zinc(II) in good yield. Characterization of the ligand and complexes was carried out using IR, NMR, electronic absorption, magnetic susceptibility, molar conductivity and elemental analysis. Anticancer activity of the prepared ligand and its complexes against breast cancer cell line MCF‐7 was determined. The anticancer activity of the new complexes was accompanied by significant increase in the activity of superoxide dismutase, with a parallel decrease in the activities of catalase and glutathione peroxidase and reduced glutathione level. Accordingly, the overproduction of free radicals allowed reactive oxygen species‐mediated cancer cell death. The results suggest that the complexes possess significant anticancer activity comparable to cisplatin. Copyright © 2012 John Wiley & Sons, Ltd.     

A chelating resin containing trihydroxybenzoic acid as the functional group: synthesis and adsorption behavior for Th(IV) and U(VI) ions

A novel glycidyl methacrylate chelating resin has been synthesized through copolymerization of glycidyl methacrylate (GMA) in the presence of divinylbenzene (DVB), the resulting resin was immobilized with 3,4,5-trihydroxybenzoic acid (THBA) to give GMA/DVB/THBA chelating resin. The adsorption of Th(IV) and U(VI) on GMA/DVB/THBA adsorbent was studied as a function of initial concentration, pH, shaking time and temperature. The novel chelating resin shows a high capacity for Th(IV) and U(VI), maximum adsorption of Th(IV) and U(VI) were 56 and 83.6 mg/g, respectively. Kinetic studies showed that the adsorption follows the pseudo second order model referring to the influence of the textural properties of the resin on the rate of adsorption. Thermodynamic parameters such as ?H° and ?S° were studied and indicated an endothermic process.     

Unit groups of some multiquadratic number fields and 2-class groups

Periodica Mathematica Hungarica - Let $$p\equiv -q \equiv 5\pmod 8$$ be two prime integers. In this paper, we investigate the unit groups of the fields $$ L_1 =\mathbb {Q}(\sqrt{2}, \sqrt{p},...     

Simultaneous identification of rutin,chlorogenic acid and gallic acid in Moringa oleifera by densitometric high-performance thin-layer chromatography method

JPC – Journal of Planar Chromatography – Modern TLC - An HPTLC (high-performance thin-layer chromatography) method was carried out to develop a feasible, simple and accurate method for...     

The influence of ultrasonic irradiation on catalytic performance of ZnO nanoparticles toward the synthesis of chiral 1-substituted-1H-tetrazolederivatives from α-amino acid ethyl esters

In this work, a simple and greener protocol for the synthesis of 1-substituted 1H-tetrazole derived from α-amino acid ethyl esters was demonstrated in the presence of zinc oxide nanoparticles (ZnO NPs) under conventional conditions, with heating (at 60 and 80°C and under reflux) compared with ultrasonic. The effect of solvent was investigated to reveal that the solvent system CH₃CN/H₂O was optimum to obtain 1-substituted 1H-tetrazole in high yield. In addition, the effect of irradiation power was studied, which showed that the yield of the reaction was improved at 200 W and the reaction time was shortened to be 30 min. Also, an improvement in the rate of the reaction and the yield of the products was observed when reactions were carried out under sonication conditions in the presence of ZnO NPs compared with conventional methods using various zinc salts as catalysts. The yields of tetrazole compounds 2a–i under sonication were determined (88–96%). Furthermore, the investigated heterogeneous catalytic system was recycled and reused for five runs with significant production of tetrazole 2a as a model target compound in excellent yields at each reaction cycle. In general, the investigated synthetic strategy for the heterocyclization of α-amino acid ethyl ester derivatives to 1-substituted 1H-tetrazoles was in agreement with the green chemistry point of view.