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.     

Structure-type separation of diesel fuels by solid phase extraction and identification of the two- and three-ring aromatics by capillary GC-mass spectrometry

A simple and effective solid phase extraction (SPE) method using silica gel micro glass columns has been developed for the separation of diesel fuel into groups of aliphatic, and mono-, di- and polyaromatic hydrocarbons. It is based on a stepwise gradient of dichloromethane in n-pentane. The resulting fractions were analyzed by capillary gas chromatography with a flame ionization detector and coupled gas chromatography-mass spectrometry. Commercially available standards, and retention indices and mass spectra were used for identification of individual aromatic compounds. The principal polycyclic aromatic hydrocarbons (PAHs) in diesel fuel are naphthalene, biphenyl, fluorene, phen-anthrene and their alkylated derivatives. Sulfur-containing PAHs are mainly represented by methyl-substituted dibenzo-thiophenes.     

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.     

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.     

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.     

Chlorinated di- and triphenylmethanes in sediments of the Mulde and Elbe rivers

Congeneric groups of chlorinated diphenylmethanes (ClDPM) and triphenylmethanes (ClTPM) identified by coupled GC/MS investigations of Elbe and Mulde river sediments were not as yet noticed as environmental contaminants of aquatic sediments. ClDPM and ClTPM are structurally related to other polychlorinated aromatic compounds and form complex mixtures of congeners. Individual ClDPM/ClTPM as well as mixtures of congerers were synthesized, and served as reference compounds for isomer identification and quantitative analysis. In addition to mass spectra, GC/FTIR-investigations and retention indices proved to be valuable for structural assignments. Sediments from the Mulde river contained up to 220 μg/kg ClTPM and 170 μg/kg ClDPM. The spatial distribution of ClDPM/TPM concentrations indicated a strong localized source of emisson at the lower Mulde river, from where the compounds enter sediments and suspended matter of the Elbe river. The occurrence of ClTPM in the Hamburg harbour at comparable levels in samples of recent and older sediments indicates emissions over a prolonged period.     

Crack edge displacement and elastic constant determination for an orthotropic material

A method for determining the elastic constants of an isotropic material, based on crack edge displacement data, is extended to an orthotropic material. Complex potentials are used to obtain the stresses and displacements for plane strain. Mode I crack problems in three mutually orthogonal planes are considered and solved. In particular, the expressions of crack edge displacements are obtained in an explicit form. An iterative statistical identification method, based on a Bayesan approach, is used to identify the elastic constants of an orthotropic medium from the Mode I crack displacements measured from the mid-point of the crack. Some graphics are displayed to illustrate the convergence of the pertinent parameters and the approach of the analytical displacements to their experimental values.