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  • 1
    Electronic Resource
    Electronic Resource
    Studies on the active molecular species of the H2-receptor antagonists cimetidine and mifentidine (1987)
    s.l. : American Chemical Society
    Journal of medicinal chemistry 30 (1987), S. 208-211 
    Details
    ISSN: 1520-4804
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/jm00384a036
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  • 2
    Electronic Resource
    Electronic Resource
    Preparation of symmetrical aryl sulfoxides from N,N-thionyldiimidazole (1968)
    s.l. : American Chemical Society
    The @journal of organic chemistry 33 (1968), S. 846-847 
    Details
    ISSN: 1520-6904
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/jo01266a082
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  • 3
    Electronic Resource
    Electronic Resource
    Substituent effect on the stereochemistry of H2-receptor antagonists of the phenylformamidine series. A conformation-dependent mode of interaction with the H2 receptor (1991)
    s.l. : American Chemical Society
    Journal of medicinal chemistry 34 (1991), S. 1772-1776 
    Details
    ISSN: 1520-4804
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/jm00110a004
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  • 4
    Electronic Resource
    Electronic Resource
    Combined non-enzymatic and enzymatic reduction favors bioactivation of racemic lipoic acid: an advantage of a racemic drug? (1997)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 9 (1997), S. 362-366 
    Details
    ISSN: 0899-0042
    Keywords: lipoic acid ; reduction ; dihydrolipoamide dehydrogenase ; antioxidant ; enantiomers ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: For the antioxidant effect of lipoic acid, reduction to dihydrolipoic acid is considered to be important. Dihydrolipoamide dehydrogenase (LipHD) preferentially reduces R-lipoic acid and in a subsequent reaction, the R-dihydrolipoic acid formed may non-enzymatically reduce S-lipoic acid. Using circular dichroism (CD) spectroscopy, the second order rate constant of the latter reaction was determined (k2 = 15 M-1 sec-1). In vitro, it was found that S-lipoic acid is reduced by LipDH using R-lipoic acid as a catalyst. The non-enzymatic dithiol-disulfide reaction leads to synergistic reduction of the enantiomers which can explain the higher antioxidant activity of racemic lipoic acid found in vivo (Maitra et al. Biochem. Biophys. Res. Commun. 221:422-429, 1996) in comparison to the enantiomers. Lipoic acid is therapeutically active in several diseases via antioxidant activity. These findings suggest that racemic lipoic acid can be therapeutically more active than the separate enantiomers. Chirality 9:362-366, 1997. © 1997 Wiley-Liss, Inc.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    1.3-Dipolare Cycloadditionen, 68. Additionen der Nitriloxide an CN-Mehrfachbindungen (1972)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 105 (1972), S. 2825-2840 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 1.3-Dipolar Cycloadditions, 68. Additions of Nitrile Oxides to CN-Multiple BondsAzomethines with aromatic or aliphatic substituents (aldimines, ketimines) react with benzonitrile oxide to give Δ2-1.2.4-oxadiazolines in good yields (19 examples). 2.4.6-Trimethyl-benzonitrile oxide combines with phenyl isocyanate to give the 1.2.4-oxadiazolin-5-one 25. The cycloaddition of nitrile oxides to nitriles leads to 1.2.4-oxadiazoles (14 examples). Here the in situ technique in generation of the nitrile oxide is advantageous, because nitriles are dipolarophiles of lower activity than azomethines. Aromatic nitriles are sufficiently active as are aliphatic nitriles with electron-attracting substituents.
    Notes: Aromatisch und aliphatisch substituierte Azomethine (Aldimine, Ketimine) treten mit Benzonitriloxid zu Δ2-1.2.4-Oxadiazolinen in guter Ausbeute zusammen (19 Beispiele). 2.4.6-Trimethyl-benzonitriloxid vereinigt sich mit Phenylisocyanat zum 1.2.4-Oxadiazolinon-(5) 25. Für die zu 1.2.4-Oxadiazolen führende Addition von Nitriloxiden an Nitrile (14 Beispiele) bewährt sich die in situ-Arbeitsweise; Nitrile sind schwächere Dipolarophile als Azomethine. Aromatische Nitrile sowie elektronenanziehend substituierte aliphatische Nitrile sind genügend aktiv.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19721050908
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  • 6
    Electronic Resource
    Electronic Resource
    1,3-Dipolare Cycloadditionen, 73. Relative Dipolarophilen- Aktivitäten bei Cycloadditionen des Benzonitriloxids (1973)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 106 (1973), S. 3312-3344 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 1,3-Dipolar Cycloadditions, 73. Relative Dipolarophile Activities in Cycloadditions of Benzonitrile OxideThe cornpetition of pairs of dipolarophiles for benzonitrile oxide, liberated in situ from benzohydroximoyl chloride (4), allows evaluation of the relative addition constants of 39 dipolarophiles which cover a range of four powers of ten. Benzonitrile oxide belongs to the type of 1,3-dipoles which react faster both with electron-deficient and electron-rich multiple bonds than with common alkenes and alkynes. Combination of these data with the known orientations provides the partial rate factors for the two directions of cycloaddition. The additivity of substituent contributions to the free energy of activation is only fulfilled to a first approximation.  -  The specific dipolarophile scale of benzonitrile oxide, as well as the orientation phenomena, are discussed in the light of the new MO perturbation treatments of Sustmann and Houk. The dipolarophile activity sequence of benzonitrile oxide is compared with those of diphenylnitrilimine and N-methyl-C-phenylnitrone.
    Notes: Die Konkurrenz von Dipolarophilen-Paaren um Benzonitriloxid,. In situ aus Benzohydroximoylchlorid (4) freigesetzt, ergab die sich über 4 Zehnerpotenzen erstreckenden relativen Additionskonstanten von 39 Dipolarophilen. Benzonitriloxid gehört zu den 1,3-Dipolen, die sowohl mit elektronen-armen als auch mit elektronen-reichen Mehrfachbindungen rascher reagieren als mit gewöhnlichen Alkenen und Alkinen. Die Kombination mit den bekannten Orientierungsverhältnissen erbrachte partielle Geschwindigkeitskonstanten der beiden Additionsrichtungen. Die Additivität der Substituenten-Beiträge zur freien Aktivierungsenergie ist nur näherungsweise erfüllt.  -  Die spezifische Dipolarophilen-Skala des Benzonitriloxids sowie die Orientierungsphänomene werden im Lichte neuer MO-störungstheoretischer Behandlungen von Sustmann und Houk diskutiert. Die Aktivitätssequenz wird mit denjenigen des Diphenylnitrilimins und des N-Methyl-C-phenylnitrons verglichen.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19731061018
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  • 7
    Electronic Resource
    Electronic Resource
    1,3-Dipolare Cycloadditionen, 70. Additionen des Benzonitriloxids an olefinische und acetylenische Dipolarophile (1973)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 106 (1973), S. 3258-3274 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 1,3-Dipolar Cycloadditions, 70. Additions of Benzonitrile Oxide to Olefinic and Acetylenic DipolarophilesBenzonitrile oxide (2) forms with monosubstituted ethylenes and acetylenes 2-isoxazolines (3-10) and isoxazoles (29, 42) substituted in the 5-position. β-Substituted styrenes yield a mixture of two possible orientation isomers (17/18, 19/20), except β-pyrrolidinostyrene, which produces only 3,4-diphenyl-5-pyrrolidino-2-isoxazoline (22). In other enamines, too, the amino function dictates this direction of addition notwithstanding steric effects. The stereospecificity of the cycloaddition has been shown by the reactions of the cis-trans-isomeric 2-butenes and stilbenes (13-16). Besides cyclopentene the less reactive cyclohexene could be combined with benzonitrile oxide (36, 37). The labile bicyclic primary adduct of cyclooctatetraene (38) undergoes electrocyclic ring closure to form the tricyclic product 39.
    Notes: Benzonitriloxid (2) bildet mit monosubstituierten Äthylenen und Acetylenen 2-Isoxazoline (3-10) und Isoxazole (29, 42), bei denen der Rest in der 5-Position erscheint. Ein Gemisch der beiden möglichen Orientierungsisomeren (17/18, 19/20) geht aus den Additionen an β-substituierte Styrole hervor. Abweichend verhielt sich β-Pyrrolidinostyrol, aus dem mit Benzonitriloxid nur 3,4-Diphenyl-5-pyrrolidino-2-isoxazolin (22) entsteht. Auch bei anderen Enaminen diktiert die Aminfunktion ungeachtet sterischer Effekte diese Additionsrichtung. Die Stereospezifität der Cycloaddition wurde an den cis-trans-isomeren 2-Butenen und Stilbenen dargetan (13-16). Neben Cyclopenten wurde auch das reaktionsträgere Cyclohexen zur Reaktion gebracht (36, 37). Das labile bicyclische Primäraddukt des Cyclooctatetraens (38) erleidet einen elektrocyclischen Ringschluß zum tricyclischen Produkt 39.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19731061015
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  • 8
    Electronic Resource
    Electronic Resource
    Experimental conditions influence [3H]-dihydroalprenolol binding characteristics to living HeLa cells due to morphological changes: A warning (1987)
    New York, NY [u.a.] : Wiley-Blackwell
    Cell Biochemistry and Function 5 (1987), S. 143-147 
    Details
    ISSN: 0263-6484
    Keywords: Radioligand binding ; HeLa cells ; beta-adrenergic receptor ; cell morphology ; non-specific binding ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Harvesting of plated growing HeLa cells, followed by incubation of these cells without any addition at 37°C was found to cause changes in the cell shape. This phenomenon is accompanied by a diminished binding of the beta-adrenergic antagonist [3H]-dihydroalprenolol and the alpha-adrenergic antagonist phentolamine to a binding compartment not representing beta-adrenergic receptors. These binding sites have a high affinity for hydrophobic agents and most probably represent lipophilic structures in the cellular membrane. Changes in the cell shape obviously cause alterations in the physical properties of the plasma membrane. This might lead to misinterpretations of the results from experiments in which the redistribution of beta-adrenergic receptors is followed during incubation with agonists, as receptor occupation with subsequent receptor redistribution is possibly accompanied by effects on the membrane microviscosity.It is concluded that investigations performed in order to follow physiological events like receptor redistribution and desensitization processes, may be obfuscated by changes in the normal physical state of the living cells.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cbf.290050210
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  • 9
    Electronic Resource
    Electronic Resource
    Über acylierende Oxydation von Cyclo-olefinen und -ketonen mit Mercurisalzen (1949)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 561 (1949), S. 165-173 
    Details
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.19495610302
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  • 10
    Electronic Resource
    Electronic Resource
    Isoquinolinium N-Arylimides and Some Cycloadditions to Heterocumulenes (1998)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1998 (1998), S. 379-385 
    Details
    ISSN: 1434-193X
    Keywords: Isoquinolinium N-arylimides ; Azomethine imines ; Cycloadditions ; Heterocycles ; 1,3-Dipoles ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The red isoquinolinium N-arylimides 19-23 are azomethine imines of which the C=N bond is part of an aromatic ring. The N-(4-nitrophenyl)imide 22 and the N-(2-pyridyl)imide 23 were obtained crystalline; in solution the latter equilibrates with the hexahydrotetrazine 24 as its dimer. The N-phenylimide 19 is not stable; an isolated solid appears to be a tetramer. Generated by deprotonation of 11-13, the N-arylimides 19-21 undergo in situ cycloadditions to carbon disulfide, phenyl isocyanate, phenyl isothiocyanate, and diphenylketene. The storable CS2 adduct 29 offers a neutral source of theN-phenylimide 19, since a cycloreversion equilibrium is established in solution.
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