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  • 1
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Journal of medicinal chemistry 33 (1990), S. 1262-1269 
    ISSN: 1520-4804
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Chemistry - A European Journal 2 (1996), S. 1335-1339 
    ISSN: 0947-6539
    Keywords: amphiphiles ; glucophospholipids ; self-assembly ; tubules ; vesicles ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A new family of amphiphiles that form tubules (i.e., hollow cylindrical bilayer-based microstructures) by self-aggregation has been identified, namely, anionic glucophospholipids of type 1, in which a double-tailed hydrophobe is grafted through a phosphate linkage to the O-6 position of a polar glucose head group. Compounds 1a-c self-assemble into stable, hollow tubular microstructures when dispersed in water and cooled below the temperature at which the transition between crystal and liquid-crystal phases takes place (estimated from change in turbidity). The diameter of the microstructures appears to depend on the nature of the hydrophobic tail, significantly smaller diameters being obtained for fluorinated tails. No tubules were obtained when galactose (2a-c, pH〈11) or mannose (3a-c) derivatives were used instead of glucose derivatives, or when glucose was derivatized at the O-3 (4b) rather than O-6 position; in these cases only vesicles were formed. Tubules made of 1 converted rapidly into giant vesicles when heated; they spontaneously formed again upon cooling. The presence of a fluorinated chain, as in 1b and 1c, increased the temperature at which the tubule-vesicle interconversion occurred to above room temperature. Because the amphiphiles are negatively charged, the formation of tubules is pH-dependent and is favored at higher pH. These findings support the view that hydration of and hydrogen bonds between polar heads play a major role in tubule formation. Hydration of the sugar-derived head groups decreases as the number of intermolecular hydrogen bonds increases; this favors membrane crystallization and tubule formation.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1022-1352
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A new family of perfluoroalkyl double-tailed amphiphiles was synthesized in order to develop a new drug carrying and delivery system. They were obtained by telomerization of tris(hydroxymethyl)acrylamidomethane (THAM) in the presence of various double-tailed primary and secondary thiols as chain-transfer agents, and with AIBN as the initiator. With secondary thiols, telomerization occurred in low yields (25-35% with respect to the thiol), because of the competitive formation of a disulfide by-product, but proceeded in higher yields (45-90%, depending on the stoichiometry of the reagents) with primary thiols, thus allowing the preparation of a new family of perfluoroalkyl telomeric THAM double-tailed amphiphiles. Preliminary biological tests showed no detectable hemolytic activity on human red blood cells at concentrations up to 20 mmol/L (50-65 g/L), whereas the hydrocarbon analogs proved to be hemolytic at 0,002 mmol/L. The LD50 was found to be higher than 2500 mg/kg of animal.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The mass spectrometry of perfluoro compounds (F-alkyl compounds) has seldom been the subject of systematic studies. Fluorocarbons excepted, only a few mass spectra of such compounds have been analysed and corresponding fragmentations correlated. In this paper we report the mass spectra of 19 amides of perfluoro acids (RFCONHR) with R=benzyl, 2-phenylethyl, 2-phenylpropyl, 3-phenylpropyl, 2-(N-phenylamino)ethyl, and RF=F-methyl, n-perfluoropropyl, n-perfluoropentyl and n-perfluoroheptyl. These compounds exhibit quite different behaviour from their hydrocarbon homologues under electron impact (for instance no [RFCO]+ fragment was found). Specific deuterium labelling and high resolution measurements have been used to show typical rearrangements and to establish the fragmentation routes.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: In this paper, the behaviour of ethers, sulfides, selenoethers, amines, germanes and stannanes, substituted on the β-C by a methoxycarbonyl, methyl ketone, or cyano group is compared and discussed. The compounds containing group VB or VIB element are quite stable, while those with a group IVB element fragment very easily. Fragmentation α to the heteroatom gives peaks for which the intensity increases with the size of the element:[PhO]+〈[PhS]+〈[PhSe]+〈[Ph3Ge]+〈[Ph3Sn]+. Fragmentation at the β position gives very important peaks when the ionization potential is low or when the substituents inductive effect is strong (CN〈CO2CH3〈COCH3).
    Notes: Nous comparons et discutons dans ce travail les résultats obtenus lors de la fragmentation d'éthers, sulfures, sélénoéthers, amines, germanes et stannanes fonctionalisés en β par un groupement méthoxycarbonyle, méthylcétone ou nitrile. Les divers composés possédant un élément de la colonne VB et VIB du tableau périodique sont relativement stables sous l'impact électronique, alors que ceux de la colonne IVB se fragmentent très facilement. Les ruptures en α de l'hétéroatome donnent des pics dont l'intensité augmente avec la taille de celui-ci: [PhO]+〈[PhS]+〈[PhSe]+〈[Ph3Ge]+〈[Ph3Sn]+. La rupture en β conduit à des fragments d'autant plus intenses que le groupement fonctionnel a un potentiel d'ionisation plus faible ou un effet inductif plus fort (CN〈CO2CH3〈COCH3).
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
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