Hypepontine,a new quaternary alkaloid with antimicrobial properties

Abstract

New isoquinoline alkaloid hypepontine (1) together with a five known compounds, were identified in Hypecoum ponticum Velen, the partial synonym of Hypecoum procumbens L. The structure of the new substance was elucidated based on spectroscopic evidence. The tertiary and quaternary alkaloid mixtures as well as the isolated alkaloids were evaluated for their antibacterial and antifungal activity. The result revealed that the crude alkaloid mixture containing quaternary isoquinoline alkaloids showed potent antifungal and antibacterial activity.     

Application of Mössbauer spectroscopy in pyritic and copper calcines studies

In the present study, Mössbauer spectroscopy is applied to the qualitative and quantitative investigation of pyritic and copper calcines prepared by the roasting of untreated concentrates and those which have received a preliminary treatment in a magnetic field. It was established that there are no significant differences in phase content between those calcines which have received a preliminary treatment and those which have not.

New phases were found in copper calcines depending on the intensifying factor applied.     

Synthesis of Gossypol Analogues

Two gossypol analogues 2a and 2b were synthesized for biological evaluation as male contraceptive agents. The naphthol 8c was prepared by analogy with a known procedure starling from 3-isopropylcatechol ( 3 ). (t-Bu)₂O₂-Mediated phenolic coupling of 8c furnished the binaphthol 9c which, after pyrane ring closure, deprotection. and selective bisformylation with SnCl₄/Cl₂CHOCH₃, gave the target compound 2a . The corresponding tetrahydroxy analogue 2b was prepared in a similar way.     

Intermediate Jacobians and Chow groups of threefolds with a pencil of del Pezzo surfaces

Summary In this paper we study threefolds with a pencil of del Pezzo surfaces with 1K²5. The curve which parametrises the exceptional curves on the fibers and the incidence correspondence on it determine a Prym-Tjurin variety which is an abelian subvariety of the Jacobian of the curve. Under certain restrictions on the singular fibers of the pencil we prove that there is a polarized isomorphism between the intermediate Jacobian of the threefold and the Prym-Tjurin variety and an isomorphism between the latter and the Chow group of algebraic one-cycles algebraically equivalent to zero.     

Darstellung und Eigenschaften von Trinorbornylbor-Verbindungen

Synthesis and Properties of Trinorbornyl Boron Compounds Tris(1-norbornyl), Tris(2-norbornyl), and Tris(7-norbornyl) boron were synthesized from boron trifluoride diethylether and 1-norbornyl lithium or 2- and 7-norbornyl magnesium halides respectively. The compounds were characterized by the IR-, ¹³C-, ¹¹B-NMR, and mass spectra. Furthermore 1-norbornyl lithium was isolated in the crystalline state and investigated in detail.     

POPs: a QSAR system for developing categories for persistent, bioaccumulative and toxic chemicals and their metabolites

This paper presents the framework of a QSAR-based decision support system which provides a rapid screening of potential hazards, classification of chemicals with respect to risk management thresholds, and estimation of missing data for the early stages of risk assessment. At the simplest level, the framework is designed to rank hundreds of chemicals according to their profile of persistence, bioaccumulation potential and toxicity often called the persistent organic pollutant (POP) profile or the PBT (persistent bioaccumulative toxicant) profile. The only input data are the chemical structure. The POPs framework enables decision makers to introduce the risk management thresholds used in the classification of chemicals under various authorities. Finally, the POPs framework advances hazard identification by integrating a metabolic simulator that generates metabolic map for each parent chemical. Both the parent chemicals and plausible metabolites are systematically evaluated for metabolic activation and POPs profile.     

Le chlorure de triphényltétrazolium en tant que réactif en chimie analytique — V

Résumé On a élaboré une méthode de dosage de petites quantités de cobalt. La méthode repose sur l'action mutuelle des ions complexes thiocyanate de cobalt-chlorure de triphényltétrazolium. On extrait le composé obtenu par le chloroforme. La solution est d'un bleu intense et présente un maximum d'absorption pour la longueur d'onde =620 nm.On masque les ions secondaires par le thiosulfate de sodium et le fluorure d'ammonium.L'erreur relative moyenne s'élève à 1,88%.La méthode de dosage du cobalt par le chlorure de triphényltétrazolium est spécifique, rapide et facile à exécuter. Elle n'exige pas la séparation des ions secondaires dans le cas de nombreux matériaux.

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Summary A method has been developed for the determination of small amounts of cobalt. The method is based on the mutual action of the complex thiocyanate ions of cobalt and the chloride of triphenyltetrazolium. The resulting compound is extracted with chloroform. The solution has an intense blue color and shows an absorption maximum for the wave length =620 nm. The secondary ions are masked by sodium thiosulfate and ammonium fluoride. The mean relative error may reach 1.88%. The method of determining cobalt by means of the triphenyltetrazolium is specific, rapid and easily conducted. It does not require the removal of the secondary ions in the case of numerous materials.

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Zusammenfassung Eine Methode zur Bestimmung kleiner Mengen Kobalt wurde ausgearbeitet. Sie beruht auf der Reaktion zwischen Kobaltrhodankomplex und Triphenyltetrazoliumchlorid. Das Reaktionsprodukt wird mit Chloroform extrahiert. Der Extrakt ist intensiv blau gefärbt und hat ein Absorptions-maximum bei 620 nm. Fremdionen werden mit Thiosulfat und mit Ammonium-fluorid maskiert. Der mittlere Fehler beträgt 1,88%. Das Verfahren ist spezifisch, rasch und einfach. In den meisten Fällen ist keine Abtrennung der Fremdionen nötig.

     

Darstellung und Eigenschaften von Norbornylquecksilberverbindungen

Preparation and Properties of Norbornyl Mercury Compounds Bis(1-norbornyl) and bis(2-norbornyl)mercury, 1- und 2-norbornylmercury chloride and 1-norbornylmercury i-butyl were synthesized and characterized by ¹³C-N.M.R. investigations and in case of bis(1-norbornyl) mercury also by the I.R. and mass spectrum. The ¹J(¹⁹⁹Hg? ¹³C) coupling constants of the 1-norbornyl compounds demonstrate the trans-influence of the norbornyl anion.     

Hydrogen Bonded Complexes of Acetylacetone and Methanol: HF and DFT level Study

Summary. Several possible hydrogen-bonded complexes between the tautomeric forms of acetylacetone and methanol were studied by ab initio methods using 6-311G** and D95** basis functions at the HF and DFT (B3LYP) levels of theory. The calculations were carried out for isolated molecules and solvent assisted complexes by means of the isodensity polarized model (IPCM). The theoretical frequencies were compared with the experimental IR spectrum of an equimolar mixture of acetylacetone and methanol. It was proved that the most stable H-bonded complex acetylacetone–methanol is formed between O-bonded methanol- and the enol molecule.     

Structure of Glasses of the TeO2 – MoO3 System

Structural models for glasses of the TeO₂–MoO₃ system are suggested. On the basis of X-ray and infrared spectral investigations, by comparing with known crystalline structures of TeO₂, MoO₃ and Te₂MoO₇(T₂M), it is shown that the glasses from TeO₂ to Te₂MoO₇ possess [TeO₄] and [MoO₅] groups as basic structural units. The latter are connected to form [Mo₂O₈] complexes. The glasses in the MoO₃-rich compositional range are built up of [TeO₃] and [MoO₆] polyhedra. The glass-formation tendency is discussed in relation to the role of the free electron pair and the disruption of secondary and weak primary bonds in the crystals.