Preparation of 3-arylmethylindoles as selective COX-2 inhibitors

The 3-arylmethylation of indoles using TMSOTf/Et₃SiH with a wide variety of substituted benzaldehydes has been accomplished. Under these mild Lewis acid mediated reductive conditions, it was demonstrated that indoles bearing both 6-MeSO₂ and 2-methyl substituents could be 3-arylmethylated in good to excellent yields to afford the corresponding 3-arylmethyl indoles, effective as selective COX-2 inhibitors. In addition, the viability of this method for the reductive alkylation of indoles by ketones was demonstrated and shown to be C-3 regioselective. For indoles bearing both a 6-MeSO₂ and 2-cyano substituent where this indole reductive alkylation methodology was unsuccessful, an unprecedented Pd(0) mediated arylorganozinc coupling with the requisite substituted 3-methylcarbonatomethylindole proved successful in affording the desired 2-cyano-6-MeSO₂-3-arylmethylindoles effective as selective COX-2 inhibitors.     

In–CuInS2 nanocomposite film prepared by pulsed laser deposition using a single source precursor

An In–CuInS₂ nanocomposite film has been prepared by Pulsed Laser Deposition applying a single source precursor. X-ray powder diffraction, Raman spectroscopy and transmission electron microscopy observations evidence that the film consists of nanocrystals of elemental In and chalcopyrite type CuInS₂ with sizes of 36 and 17 nm respectively. A detailed analysis of the electrical performance of the film suggests that the nanoparticles are in Ohmic contact and that the resistivity is mainly caused by the CuInS₂ nanocrystals which are less conducting than the pure In metal. Irradiation of the film with light shows a photoconductive effect mainly with wavelengths larger than 515 nm and smaller than 850 nm.     

Pteridines,Part CXI,Pteridine‐Based Photoaffinity Probes for Nitric Oxide Synthase and Aromatic Amino Acid Hydroxylases

Various 6‐substituted pteridines and 5,6,7,8‐tetrahydropterins carrying photolabile functions at the side chain (see 7 , 20 – 22 , 34 – 36 , 38 , and 39 ) as well as at the 5‐position (see 27 – 29 ) were synthesized from pterin and from 6‐phenylpterin ( 1 ) and 6‐(hydroxymethyl)pterin ( 10 ). Attachment of the photoaffinity labels via ester bonds required a special protecting‐group strategy based upon acid‐labile (see 30 – 33 ) and β‐eliminating blocking groups (see 17 – 19 ). The 6‐(4‐azidophenyl)pterin ( 7 ) was obtained from 6‐phenylpterin ( 1 ) via intermediates 2 and 4 – 6 , due to the low solubility of simple pterins in general. The pteridine derivatives 21 , 22 , 25 , 26 , 28 , 29 , 32 , 33 , 35 , 36 , 38 , and 39 were screened as inhibitors of neuronal (type I) NO synthase (see Table) from porcine cerebellum, of which 22 , 35 , 36 , and 38 showed interesting inhibitory activity with similar potency and effectiveness.     

Selective solid phase extraction of propranolol on multiwell membrane filter plates modified with molecularly imprinted polymer

Molecularly imprinted polymers (MIPs) were synthesized in 24-well glass fiber membrane filter plates to obtain a novel type of solid phase extraction device for the cleanup of propranolol. Sample processing parameters like residence time during sample loading, sample volume, pH, sample solvent, type and amount of washing and elution solvents were investigated and optimized. Important differences from the traditional molecularly imprinted solid phase extraction (MISPE) cartridges have been identified. The MIP modified composite membrane suits well for the sample preparation of low volume biological samples. A protocol has been elaborated for the quantitation of propranolol from urine and plasma samples in the clinically relevant concentration ranges. Preliminary validation results indicate that the composite MIP membrane filter plates offer a viable alternative to existing MISPE cartridges and at the same time have advantages like much easier and faster synthesis method and high-throughput analysis.     

Upper and lower bounds to eigenvalues

The variational method based on the Temple-Kato formulae is applied to the determination of bounds for some ^1,3 P(1s np) states of He.

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Zusammenfassung Die Variationsmethode, die auf der Temple-Kato Formel beruht, wird angewandt zur Bestimmung der Grenzen für einige ^1,3 P(1s np)-ZustÄnde des He.

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Résumé La méthode variationnelle basée sur la formulation de Temple-Kato est appliquée à la détermination de limites pour certains états ^1,3 P(1s np) de He.

     

The kinetics of charging and discharging of iridium oxide films in aqueous and non-aqueous media

Cyclic voltammetry and chronocoulometry have been used to investigate the kinetics of oxidation and reduction of electrochenucally generated Ir oxide films in H₂SO₄(aq), basic aqueous LiClO₄ solutions and LiClO₄ + acetonitrile solutions. In acidic aqueous solutions, the scan rate at which the main anodic peak potential begins to shift positively in cyclic voltammetry experiments has been used as a parameter to assess the charging and discharging kinetics of Ir oxide films grown under various conditions. In acidic and basic aqueous solutions, chronocoulometric measurements indicate that electron transport through the oxide is rate limiting for the main redox wave, whereas ion transport probably limits the charging/discharging kinetics in LiClO₄ + CH₃CN solutions. In this non-aqueous medium, it appears that ca. 35% of the oxide sites charge and discharge approximately an order of magnitude more rapidly than the remaining sites.     

Determination of nifedipine in human plasma by high performance liquid chromatography using column-switching technique

A highly sensitive reversed-phase HPLC method has been developed for the determination of nifedipine in human plasma with electrochemical detection. A liquid-liquid extraction procedure is used in sample preparation with an average extraction recovery of 75%. Removing the highly lipophilic plasma components using a special column switching technique reduced the duration of the HPLC measurement from 30 to 9 min. The method is applicable for the pharmacokinetic characterization and bioavailability study of a sustained-release (retard) formulation of nifedipine and for human drug monitoring as it is indicated by the validation of the analysis method. The assay gave a linear response over the concentration range 2.5–50 ng/ml. All the validation parameters are within the internationally required limits.     

Antibacterial and Chemical Characterization of Silica-Quercetin-PEG Hybrid Materials Synthesized by Sol–Gel Route

This paper aims to synthesize, via the sol–gel method, a biomaterial usable in the medical field. Here, the silica-PEG-quercetin system was evaluated in relation to the different concentrations of PEG (0, 6, 12, 24, 50 wt%) and quercetin (0, 5, 10, 15 wt%), respectively. In addition, Fourier Transform-Infrared spectroscopy (FT-IR), Scanning Electron Microscopy (SEM), and Kirby–Bauer analyses were performed. FT-IR was used to evaluate the hybrid formation and the influence of both PEG and Quercetin in the hybrid synthesized materials, SEM was used to evaluate the morphological properties, while the Kirby–Bauer test was used to understand the ability of the materials to inhibit the growth of the assayed bacterial strains (Escherichia coli, Pseudomonas aeruginosa, Enterococcus faecalis, and Staphylococcus aureus).     

Intergrowth Phases of Tetragonal Rare Earth Boride Carbides

Tetragonal rare earth boride carbides with structure types derived from La₅B₂C₆ and Sc₃C₄, respectively, can intergrow coherently. Slabs of both types with various thicknesses from one unit‐cell parameter up to macroscopic domains may grow together, sharing a common square net of metal atoms. There is a tendency towards phase separation in order to achieve long‐range order. However, phasoid‐like crystallites have also been observed. Long‐range order is also achieved by the formation of ordered intergrowth compounds. They are characterised by a regular periodic sequence of lamellar slabs (each of one or a few unit cells thickness) of both basic structure types.