3′-Methylsulfinyl-3,4′-diquinolinyl sulfides

Reactions of 4-methoxy- or 1,4-dihydro-4-oxo-3′-methylthio-3,4′-diquinolinyl sulfides 1 and 7 with a nitrating mixture ran as the 3′-methylthio group 5-mono-oxidation followed by C₆- and C₈-nitration and led to the mixture composed of products 3, 4, 5 and 6 (in the case of substrate 1 ) or compounds 5 and 6 (for substrate 7 ). In the reaction with hydrochloric acid 4-methoxy-3′-methylsulfinyl-3,4′-diquinolinyl sulfides 3 and 4 could be hydrolysed to 3′-methylsulfinyl-4(1H)-quinolinones 5 or 6 respectively, the methylsulfinyl group remaining unaffected.     

Skin Necrosis due to Photodynamic Action of Benzoporphyrin Depends on Circulating Rather than Tissue Drug Levels: Implications for Control of Photodynamic Therapy

In an ideal world, photodynamic therapy (PDT) of abnormal tissue would reliably spare the surrounding normal tissue. Normal tissue responses set the limits for light and drug dosimetry. The threshold fluence for necrosis (TFN) was measured in normal skin following intravenous infusion with a photosensitizer, benzoporphyrin derivative monoacid ring A (BPD-MA) Verteporfin as a function of drug dose (0.25-2.0 mg/kg), wavelength of irradiation (458 and 690 nm) and time interval (0–5h) between drug administration and irradiation. The BPD-MA levels were measured in plasma and skin tissue to elucidate the relationship between TFN, drug kinetics and biodistribution. The PDT response of normal skin was highly reproducible. The TFN for 458 and 690 nm wavelengths was nearly identical and the estimated quantum efficiency for skin response was equal at these two wavelengths. Skin phototoxicity, quantified in terms of 1/ TFN, closely correlated with the plasma pharmacokinetics rather than the tissue pharmacokinetics and was quadratically dependent on the plasma drug concentration regardless of the administered drug dose or time interval between drug and light exposure. This study strongly suggests that noninvasive measurements of the circulating drug level at the time of light treatment will be important for setting optimal light dosimetry for PDT with liposomal BPD-MA, a vascular photosensitizer.     

Determination of lithium in pharmaceutical formulations used in the treatment of bipolar disorder by flow injection analysis with spectrophotometric detection

In this work, a flow injection system with spectrophotometric detection was developed for the determination of lithium in pharmaceutical formulations used in the treatment of bipolar disorder. Reaction between Quinizarine (1,4-dihydroxyanthraquinone) and Li(I) ion in alkaline medium containing dimethylsulfoxide (DMSO) was explored for this purpose. The flow system was optimized regarding to its chemical (DMSO, Quinizarine and NaOH concentrations and sample pH) and physical parameters (sample loop volume, carrier flow rate and reactor length) in order to establish better conditions in terms of sensitivity and sampling frequency. The results obtained showed that the concentration of DMSO in the reagent solution presents remarkable influence on the magnitude of analytical signal. Chemical species that could be found in the formulations such as Na(I), K(I), Mg(II), Ca(II), Ti(IV), Cl⁻, CO₃²⁻ e sodium dodecylsulfate were tested as possible interfering ions. Among them, only non-monovalent cations presented noticeable interference on lithium signal. However, they were not found in concentrations high enough to cause interference in the determination of lithium in the samples. Sample preparation was performed by sonicating a slurry prepared by dispersing 100 mg of powdered sample in 15 mL of 0.10 mol L⁻¹ HCl solution. Results obtained by developed methodology were not statistically different from those obtained by flame emission spectrometry. In the optimized conditions the method presented a linear range of 5-40 mg L⁻¹ and a relative standard deviation of 3.6% at 5 mg L⁻¹ Li concentration. Detection and quantification limits were 0.54 and 1.8 mg L⁻¹, respectively. Sampling frequency, calculated as the time interval passed between two consecutive injections, was 60 samples per hour. The methodology was successfully applied in the determination of lithium in three commercial samples.     

Derivate des Methylendioxybenzols, 7. Mitt.: Über die Einwirkung nucleophiler Reagenzien auf Myristicinabkömmlinge

Zusammenfassung In dieser Arbeit wird über die alkalische Verseifung des 2,6-Dinitro-myristicinsäuremethylesters berichtet, die zur Spaltung der Methylendioxygruppierung unter, Bildung von neuen Phenoläthern führt. Weiterhin werden Amino-myristicinsäuremethylester mit Alkyl-, Aryl- und heterocyclischen Säurechloriden acyliert und die entstehenden Acylaminoderivate durch Behandlung mit Hydrazinhydrat in die entsprechenden Aminochinazolone übergeführt. Additions-, Substitutions- und Abspaltungsreaktionen der N-ständigen Aminogruppe des 2-Methyl-3-amino-6,7-methylendioxy-8-methoxy-chinazolons-(4) waren schließlich Gegenstand unserer Untersuchungen.     

Aureomycin nitrate,its preparation and identification

Summary Aureomycin hydrochloride does not show any promise as a reagent for qualitative detection or quantitative estimation of any of the common cations or aidons. The well developed crystals of the rather insoluble nitrate may be used for the identification of aureomycin. The low solubility of the nitrate may give a better stability as compared with the hydrochloride, which would be of interest to the pharmacist.

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Zusammenfassung Versuche mit Aureomycinhydrochlorid gaben keine Anhaltspunkte für eine Eignung dieser Verbindung als Reagens für die Auffindung oder Bestimmung der häufig angetroffenen Kationen oder Anionen. Die gut ausgebildeten Kristalle des wenig löslichen Nitrats können für die Erkennung von Aureomycin benützt werden. Die geringe Löslichkeit des Nitrats erhöht dessen Beständigkeit im Vergleich zum Hydrochlorid, was für Pharmazeuten von Interesse sein könnte.

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Résumé Le chlorhydrate d'auréomycine ne montre aucune propriété intéressante comme réactif de recherche qualitative ou d'estimation quantitative des cations et anions courants. On peut utiliser les cristaux bien développés de son nitrate assez peu soluble pour identifier l'auréomycine. La faible solubilité de ce nitrate peut lui conférer une meilleure stabilité que celle du chlorure ce qui est digne d'intérêt pour les pharmaciens.

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Dedicated to Prof. Dr.Hans Lieb at his 70th birthday.     

Stereoselective diversity-oriented solution and solid-phase synthesis of tetrahydroquinoline-based polycyclic derivatives

A diversity-oriented solution and solid-phase synthesis of tetrahydroquinoline-based tricyclic derivatives has been achieved from enantiomerically pure, natural product-like bicyclic scaffold. The solution synthesis of enantiopure bicyclic scaffold was developed by asymmetric hetero Michael reaction. Our approach for the synthesis of polycyclic derivatives utilized regio- and stereoselective hetero Michael reaction and ring-closing metathesis as key steps in solution and on solid phase.     

Comparison of silanization/hydrosilation and organosilanization modification procedures on etched capillaries for electrokinetic chromatography

Etched capillaries for use in open tubular electrochromatography are modified by silanization/hydrosilation and organosilanization. The migration behavior of both types of capillaries is evaluated with small basic molecules, peptides and proteins. Comparisons of peak symmetry and efficiency are used to measure the effectiveness of the two methods for modifying the etched surface. From this information, the suitability of each method for use with etched capillaries can be determined.     

Nuclear magnetic resonance studies of sulfur inversion in bis(cyclopentadienyl)-molybdenum and -tungsten complexes with dithioethers

The metallocene thioether derivatives [Cp₂M(MeSCH₂CH₂SMe)][PF₆]₂ (1, M = MO; 2, M = W), [Cp₂Mo(SCH₂CH₂SMe)][PF₆] (3) and [Cp₂M(SCH₂CH₂S)] (4, M = Mo; 5, M = W) exhibit temperature-dependent fluxional behavior in solution, owing to the pyramidal sulfur inversion process. The activation energies for this process were determined from proton band-shape analysis in the cases of 1 (54.9 ± 2 kJ mol⁻¹), 2 (51.2 ± 4.6 kJ mol⁻¹) and 3 (30.0 ± 3.1 kJ mol⁻¹). Extended Hückel calculations on related model complexes suggest that local inversion at the sulfur atoms, rather that an inversion of the complete S---C---C---S chain, is responsible for the observed fluxional behaviour.     

Solution- and solid-phase synthesis of natural product-like tetrahydroquinoline-based polycyclics having a medium size ring

A solid-phase synthesis of tetrahydroquinoline-derived polycyclic 4, having a medium size ring with an enamide functionality, was achieved from tetrahydroquinoline derivative 3 in five steps with overall 40-45% yield. An enantiopure, tetrahydroquinoline-derived beta-amino ester, 1, was converted into compound 2 that has a free phenolic hydroxyl group as an anchoring site for solid-phase synthesis. The solid-phase worked well for this sequence, in which the synthesis of the unsaturated eight-membered enamide lactam was obtained by a ring-closing metathesis approach. Compound 4 is a novel, natural product-like polycyclic derivative that could further be utilized in library generation for developing small molecule chemical probes.     

Anion-pi interactions in cyanuric acids: a combined crystallographic and computational study

Several structures of pi complexes of isocyanuric acid and of several thio derivatives with anions have been computed by using high level ab initio calculations. The nature of the complexes has been studied by means of the method of molecular interaction potential with polarization (MIPp) and Bader's theory of atoms-in-molecules. These molecules form favorable complexes with anions and can be used as binding units for building receptors for the molecular recognition of anions. In several cases, the anion-pi interaction has been demonstrated experimentally by means of X-ray crystallography.