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  • 1
    Electronic Resource
    Electronic Resource
    Cyanopeptolin S, a sulfate-containing depsipeptide from a water bloom of Microcystis sp. (1995)
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology letters 129 (1995), S. 0 
    Details
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Abstract A new sulfated, cyclic depsipeptide, called cyanopeptolin S, from Microcystis sp. was isolated from a water bloom in the Auensee/Leipzig (Germany). The depsipeptide had a relative molecular mass of 925 and contained l-arginine, l-threonine, l-isoleucine, N-methyl-l-phenylalanine, a l-glutamic acid-δ-aldehyde ring system and a sulfated d-configurated glyceric acid as a side chain. The structure was elucidated by means of two-dimensional 1H and 13C nuclear magnetic resonance spectroscopy, fast atom bombardment mass spectroscopy, Fourier transformed infrared spectroscopy and combined gas-liquid chromatography/mass spectrometry. Cyanopeptolin S inhibited trypsin with an IC50≤ 0.2 μg ml−1.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1574-6968.1995.tb07569.x
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  • 2
    Electronic Resource
    Electronic Resource
    New technique for the determination of interconversion processes based on capillary zone electrophoresis: Studies with axially chiral biphenyls (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 8 (1996), S. 441-445 
    Details
    ISSN: 0899-0042
    Keywords: capillary zone electrophoresis ; axially chiral biphenyls ; energy barrier ; cyclodextrin derivatives ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A new technique is presented for the investigation of the rotational energy barrier of axially chiral biphenyls, based on capillary zone electrophoresis using cyclodextrin derivatives as chiral selectors. Only minute amounts are required for the investigation of dynamic processes with energy barriers of 100-130 kJ/mol. The influence of the chiral selector on the conformational stability of atropisomers can be determined separately for each enantiomer. Additionally, segmentation of the capillary into different buffer zones allows us to exclude any influence of the chiral selector on the rotational energy barrier. © 1996 Wiley-Liss, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Enantioselective capillary gas chromatography in the investigation of stereochemical correlations of terpenoids (1998)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 10 (1998), S. 499-504 
    Details
    ISSN: 0899-0042
    Keywords: enantioselective capillary gas chromatography ; cyclodextrin derivatives ; stereochemistry of terpenes ; monoterpenes ; essential oils ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Capillary gas chromatography employing the unique selectivities of specifically substituted cyclodextrins is highly suited for stereochemical investigations of terpenoid compounds. The analysis of many essential oils have shown that monoterpene derivatives regularly occur as enantiomeric mixtures. In the case of sesquiterpene hydrocarbons, liverworts (Hepaticae) and other lower organisms usually biosynthesize compounds of opposite stereochemistry as compared to higher plants and enantiomeric mixtures occur only occasionally. The investigation of diterpene hydrocarbons has so far shown no indication of the presence of both enantiomers in the same plant. Chirality 10:499-504, 1998. © 1998 Wiley-Liss, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Determination of the enantiomeric composition of mexiletine and its four hydroxylated metabolites in urine by enantioselective capillary gas chromatography (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 8 (1996), S. 30-34 
    Details
    ISSN: 0899-0042
    Keywords: gas chromatography ; modified β-cyclodextrin column ; chiral separation ; assay ; mexiletine ; hydroxylated metabolites ; urine ; conjugation/deconjugation ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The enantiomers of mexiletine and four of its hydroxylated metabolites were directly separated by capillary gas chromatography using a heptakis(6-O-tert-butyl-dimethylsilyl-2,3-di-O-methyl)-β-cyclodextrin column. The method was applied to the analysis of urine samples from cancer patients who were treated with racemic mexiletine as part of a study of the use of mexiletine in the relief of neuropathic pain. Samples analyzed before and after deconjugation of the urine with β-glucuronidase/arylsulfatase showed a high stereoselectivity in the formation and conjugation of these compounds. © 1996 Wiley-Liss, Inc.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Stoffwechselprodukte von Mikroorganismen, 195. Konstitution von Ophiocordin, einem Antibiotikum mit antifungischen Eigenschaften (1980)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 2221-2226 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Metabolites of Microorganisms, 195. The Structure of Ophiocordin, an Antibiotic with Antifungal ActivityThe structure of the antibiotic Ophiocordin (9), which exhibits antifungal activity, was elucidated by chemical degradation, mass spectrometry, and NMR. Ophiocordin contains a novel 3-amino-hexahydro-4-hydroxyazepin system (5), which is esterified with 4-hydroxybenzoic acid and connected to 3,3′,5′-trihydroxy-2,4′-carbonylbis[benzoic acid] (7) via an amide bond between the 1-carboxy group and the amino group of the azepin system.
    Notes: Die Konstitution des antifungisch wirksamen Antibiotikums Ophiocordin (9) konnte durch chemischen Abbau, Massenspektrometrie und Kernresonanz aufgeklärt werden. Ophiocordin enthält ein neuartiges 3-Aminohexahydro-4-hydroxyazepin-System (5), an das 4-Hydroxybenzoesäure esterartig und 3,3′,5′-Trihydroxy-2,4′-carbonylbis[benzoesäure] (7) über die Carboxylgruppe in 1-Stellung säureamidartig gebunden ist.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19801130617
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  • 6
    Electronic Resource
    Electronic Resource
    Synthese der N-terminalen Aminosäure der Nikkomycine I, J, X und Z (1982)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1982 (1982), S. 1615-1622 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of the N-Terminal Amino Acid of the Nikkomycins I, J, X, and ZA mixture of four stereoisomers of 2-amino-4-hydroxy-4-(5-hydroxy-2-pyridyl)-3-methylbutanoic acid (14), the N-terminal amino acid of the nikkomycin antibiotics could be synthesized in a twelve-step procedure. By comparison of 1H NMR spectra, mass spectra and of the gas chromato-graphic behaviour of various derivatives the constitution and relative configuration of the natural compound has been confirmed.
    Notes: Ein Gemisch aus vier Stereoisomeren von 2-Amino-4-hydroxy-4-(5-hydroxy-2-pyridyl)-3-methylbuttersäure (14) der N-terminalen Aminosäure der Nikkomycin-Antibiotika konnte in einer zwölfstufigen Synthese dargestellt werden. Durch Vergleich der 1H-NMR-Spektren, Massenspektren und des gaschromatographischen Verhaltens verschiedener Derivate von Synthese- und Naturprodukt wird die Richtigkeit der angenommenen Konstitution und relativen Konfiguration bestätigt.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198219820904
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  • 7
    Electronic Resource
    Electronic Resource
    Konfiguration von 2-Amino-4-hydroxy-4-(5-hydroxy-2-pyridyl)-3-methylbuttersäure, der N-terminalen Aminosäure der Nikkomycine (1980)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1980 (1980), S. 1728-1735 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Configuration of 2-Amino-4-hydroxy-4-(5-hydroxy-2-pyridyl)-3-methylbutyric Acid, the N-Terminal Amino Acid of the NikkomycinsThe N-ethylthio(thiocarbonyl)derivative 2 of the N-terminal amino acid 1 of the nikkomycin antibiotics shows a positive Cotton effect in its circular dichroism spectrum and therefore 1 is assigned to the L-series. The relative configuration of the C atoms 3 and 4 was ascertained by 1H-NMR investigations and crystal structure analysis. Accordingly, 1 is assigned the configuration 2S,3S,4S.
    Notes: Das N-Ethylthio(thiocarbonyl)derivat 2 der N-terminalen Aminosäure 1 der Nikkomycin-Antibiotika weist Circulardichroismus mit positivem Cottoneffekt auf und 1 ist daher der L-Reihe zu-zuordnen. Die relative Konfiguration an den C-Atomen 3 und 4 wurde durch 1H-NMR- und Kristallstrukturuntersuchungen bestimmt. Danach hat 1 die Konfiguration 2S,3S,4S.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198019801112
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  • 8
    Electronic Resource
    Electronic Resource
    Reaktionen von Aminosäuren und Peptiden, IV. Synthese von Furanderivaten aus N-Methylaminosäuren (1981)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1981 (1981), S. 1606-1609 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions of Amino Acids and Peptides, IV. - Synthesis of Furan Derivatives from N-Methyl Amino AcidsIn the reaction of N-methyl homophenylalanine and N-methyl norleucine with hexafluoroacetic anhydride the expected 1,3-oxazolidin-5-one derivatives are formed only as by-products. As main products 3-[methyl(trifluoroacetyl)amino]-2,5-bis(trifluoromethyl)furan derivatives could be isolated, the structures of which were identified by spectroscopic methods.
    Notes: Bei der Reaktion von N-Methylhomophenylalanin und N-Methylnorleucin mit Hexafluoracetanhydrid entstehen die erwarteten 1,3-Oxazolidin-5-on-Derivate nur als Nebenprodukte. Als Hauptprodukte konnten 3-[Methyl(trifluoracetyl)amino]-2,5-bis(trifluormethyl)furan-Derivate isoliert werden, deren Konstitutionen mit spektroskopischen Methoden ermittelt wurden.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198119810910
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  • 9
    Electronic Resource
    Electronic Resource
    Die Struktur von Stenothricin - Korrektur eines früheren Strukturvorschlags (1984)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1984 (1984), S. 1672-1684 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The Structure of Stenothricin - Revision of a Previous Structure AssignmentA deviation from the previously assumed molecular mass was proved by fast-atom bombardment mass-spectrometry for the peptide antibiotic stenothricin. Recent investigations of a partial hydrolyzate revealed the presence of α-ketobutyrylvaline formed by hydrolysis of an α,β-dehydroaminobutyric acid (DH-Abu) moiety. Fragments obtained by partial hydrolysis of stenothricin after catalytic hydrogenation show that the previously identified tripeptide D-aThr-L-Ser-L-Dpr is linked over DH-Abu to the tetrapeptide L-Val-D-Ser-L-Lys-Sar. The carboxy group of Sar is esterified with the hydroxy group of D-aThr. The N-terminus is formed by D-cysteic acid, which is N-acylated by β-ketoacyl residues and is connected to the cyclic octapeptide lactone via the amino group of D-a Thr.
    Notes: Die durch Fast-Atom-Bombardment-Massenspektrometrie gegenüber früheren Annahmen nachgewiesene Abweichung der Molmasse von Stenothricin erforderte eine erneute Untersuchung dieses Peptidantibiotikums. Gegenüber früheren Befunden konnte im Partialhydrolysat zusätzlich α-Ketobutyrylvalin identifiziert werden, das durch Verseifung von α,β-Dehydroaminobuttersäure (DH-Abu) entsteht. Nach katalytischer Hydrierung von Stenothricin durch Partialhydrolyse erhaltene Fragmente zeigen, daß das schon früher identifizierte Tripeptid D-aThr-L-Ser-L-Dprüber DH-Abu an das Tetrapeptid L-Val-D-Ser-L-Lys-Sar gebunden ist. Die Carboxygruppe von Sar ist außerdem mit der Hydroxygruppe von D-aThr verestert. Die durch β-Ketoacylreste N-acylierte D-Cysteinsäure bildet den N-Terminus und ist über die Aminogruppe von D-aThr mit dem Octapeptidlacton verknüpft.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198419841007
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  • 10
    Electronic Resource
    Electronic Resource
    Localization of the amide function in the sequence of peptide antibiotic trichotoxin A 40 (1982)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 9 (1982), S. 39-42 
    Details
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: By treatment with trifluoroacetic acid at 37°C the octadecapeptide antibiotic complex trichotoxin A 40 could be cleaved into three homologous N-acetylated dodecapeptides and two homologous pseudohexapeptides. After separation the peptides were converted to trimethylsilylated N-ethylpolyamino alcohols and investigated by capillary gas chromatography and mass spectrometry. Mass spectrometric analysis demonstrated the presence of a glutamine residue at position 6 and of a glutamic acid residue at position 17.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200090108
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