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  • 1
    Electronic Resource
    Electronic Resource
    Cysteine-glutathione disulfide, the sperm-release pheromone of the marine polychaete Nereis succinea (Annelida: Polychaeta) (1998)
    Springer
    Chemoecology 8 (1998), S. 33-38 
    Details
    ISSN: 1423-0445
    Keywords: Key words. sex pheromone - marine invertebrates - marine polychaetes - Nereis succinea - sperm release - cysteine-glutathione disulfide - glutathione - peptides
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary. In the marine polychaete Nereis succinea (Frey & Leuckart 1847) a sex pheromone was isolated from the coelomic fluid of sexually mature females and identified by NMR studies and independent synthesis. This pheromone is released by the females during reproduction together with eggs and coelomic fluid into the free water column and induces sperm release of surrounding males. Its structure was ascertained as L-cysteine-glutathione disulfide. It exhibited a response threshold of 0.6 · 10−7 M.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/PL00001801
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  • 2
    Electronic Resource
    Electronic Resource
    'Wave-type' structure of a synthetic hexaglycosylated decapeptide: A part of the extracellular domain of human glycophorin A (1999)
    Springer
    Journal of biomolecular NMR 14 (1999), S. 33-45 
    Details
    ISSN: 1573-5001
    Keywords: glycophorin A ; glycopeptide ; MD simulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The three-dimensional structure of a glycopeptide, His-Thr*-Ser*-Thr*-Ser*-Ser*-Ser*-Val-Thr-Lys, with 2-acetamido-2-deoxy-α-D-galactose (GalNAc) residues linked to six adjacent amino acids from Thr-10 to Ser-15, was studied by NMR spectroscopy and molecular dynamics (MD) simulations. The hexaglycosylated decapeptide is part of the extracellular domain of human glycophorin A and shows an extended structure of the peptide backbone due to O-glycosylation. Furthermore, each GalNAc residue exhibits one and only one NOE contact from the NHAc proton to the backbone amide proton of the amino acid that the sugar is directly bound to. This indicates a strong preference for the orientation of all GalNAc residues towards the N-terminus. NOE build-up curves were used to determine 42 inter-proton distances that, in connection with φ angles of the peptide backbone obtained from 3J-coupling constants, resulted in constraints for a MD simulation in water. The NMR data and the MD simulations show a preference for an extended backbone structure. The GalNAc residues are located alternatingly on opposite sides of the backbone and reduce the flexibility of the peptide backbone. The conformation of the molecule is relatively rigid and shows a 'wave-type' 3D structure of the peptide backbone within the glycosylation cluster. This new structural element is also supported by the unusual CD spectrum of the glycopeptide.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008397304851
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  • 3
    Electronic Resource
    Electronic Resource
    Biotransformation of diphenyl ether by the yeastTrichosporon beigelii SBUG 752 (1995)
    Springer
    Biodegradation 6 (1995), S. 173-180 
    Details
    ISSN: 1572-9729
    Keywords: aromatic ring cleavage ; degradation ; dioxin like compounds ; diphenyl ether ; Trichosporon beigelii
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Trichosporon beigelii SBUG 752 was able to transform diphenyl ether. By TLC, HPLC, GC, GC-MS, NMR- and UV-spectroscopy, several oxidation products were identified. The primary attack was initiated by a monooxygenation step, resulting in the formation of 4-hydroxydiphenyl ether, 2-hydroxydiphenyl ether and 3-hydroxydiphenyl ether (48:47:5). Further oxidation led to 3,4-dihydroxydiphenyl ether. As a characteristic product resulting from the cleavage of an aromatic ring, the lactone of 2-hydroxy-4-phenoxymuconic acid was identified. The possible mechanism of ring cleavage to yield this metabolite is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00695348
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  • 4
    Electronic Resource
    Electronic Resource
    Stoffwechselprodukte von Mikroorganismen. 253. Mitteilung252, Mitteilung. Hormaomycin, ein neues Peptid-lacton mit morphogener Aktivität auf Streptomyceten (1989)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 72 (1989), S. 426-437 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Hormaomycin, a Novel Peptide Lactone with Morphogenetic Activity on StreptomycesA culture identified as Streptomyces griseoflavus (strain W-384) has been found to produce a novel peptide-lactone antibiotic designated hormaomycin (6). The empirical molecular formula of the compound is established to be C55H69ClN10O14. The constituent amino acids of the antibiotic are suggested to be allothreonine (1; 1), isoleucine (2; 1), 3-methyl-phenylalanine (3; 2), and, for the first time identified from a natural source, 4-[(Z)-prop-1-enyl]-proline (4; 1) and 3-(2-nitrocyclopropyl)-alanine (5; 2). The amino acids were delivered by acidic hydrolysis and assigned by high-resolution- GC/MS analysis (after transformation to derivatives) in combination with extended 2D-NMR experiments of the antibiotic itself. From the latter, it became plausible that the N-terminus of the peptide chain is acylated by a Cl-containing derivative of 1H-pyrrol-2-carboxylic acid. Hormaomycin is active against some Gram-positive bacteria. In addition, the antibiotic exhibits potent aerial mycelium-inducing activity and effects the production of antibiotics.
    Notes: No abstract.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19890720303
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  • 5
    Electronic Resource
    Electronic Resource
    Photoaddition of Ethyl 2,2-Dimethyl-5-oxo-5,6-dihydro-2H-pyridine-1-carboxylate to 2,3-dimethylbut-2-ene (1998)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 81 (1998), S. 303-306 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: On irradiation (350 nm) in the presence of excess 2,3-dimethylbut-2-ene, the newly synthesized title compound 5 affords as main products the unexpected cyclopropylpyrrolidine 10 (50%) and the spiro-oxetane 9 (25%).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19980810210
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  • 6
    Electronic Resource
    Electronic Resource
    New alkaloids from ants: Identification and synthesis of (3R,5S,9R)-3-butyl-5-(1-oxopropyl)indolizidine and (3R,5R,9R)-3-butyl-5-(1-oxopropyl)indolizidine, constituents of the poison gland secretion in Myrmicaria eumenoides (hymenoptera, formicidae)Dedicated to Professor Dr. K. Mori on the occasion of his 60th birthday. (1995)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1995 (1995), S. 965-977 
    Details
    ISSN: 0947-3440
    Keywords: Ants ; Alkaloids ; Myrmicaria eumenoides ; 3-Butyl-5-(1-oxopropyl)indolizidine, (3R,5S,9R)-,(3R,5R,9R)- ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The (3R,5S,9R) and (3R,5R,9R) stereoisomers of 3-butyl-5-(1-oxopropyl)indolizidine (9) were identified as major constituents of the poison gland secretion of the African ant, Myrmicaria eumenoides. Racemates of the four diastereomers of 9 were synthesized via the corresponding ethyl 5-(5-butylpyrrolidin-2-yl)pentanoates (6). Enantiomerically pure samples of the (3R)-stereoisomers of 9 were obtained by starting from (2R)-2,3-O-isopropylideneglyceric aldehyde (21) and 6-methylpyridine-2-carboxaldehyde (20). In addition, the enantiomeric separation by chiral gas chromatography and unambiguous structure assignment of the target compounds are described.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.1995199506138
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  • 7
    Electronic Resource
    Electronic Resource
    Ungewöhnliche Reaktion zu Glycosylurethanen bei einer Glycopeptidsynthese (1987)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1987 (1987), S. 577-581 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Unusual Reaction to Glycosyl Urethanes During a Synthesis of GlycopeptidesReaction of the disaccharide halide 1 with N-(3,5-dimethoxy-α,α-dimethylbenzyloxycarbonyl)-L-serine benzyl ester (5) unexpectedly yields the glycosyl urethane 10. Glycosidation of 5 predominantly occurs at the urethane oxygen and not at the free hydroxy group of L-serine. During the formation of 10 the β-hydroxy group of serine is converted into a 3,5-dimethoxy-α,α-dimethylbenzyl ether.
    Notes: Die Umsetzung des Disaccharidhalogenids 1 mit N-(3,5-Dimethoxy-α,α-dimethylbenzyloxycarbonyl)-L- serin-benzylester (5) führt unerwartet zum Glycosylurethan 10. Im Derivat 5 wird bevorzugt der Urethansauerstoff und nicht die freie OH-Gruppe des L-Serins glycosidiert. Während der Reaktion zu 10 erfolgt Überführung der β-OH-Gruppe des Serins in einen (3,5-Dimethoxy-α,α-dimethylbenzyl)ether.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198719870703
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  • 8
    Electronic Resource
    Electronic Resource
    Synthesen von Olivosyl-Oliosiden und spektroskopische Strukturbestimmung von Mithramycin (1986)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1986 (1986), S. 814-824 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Syntheses of Olivosyl-Oliosides and Spectroscopic Structure Assignment of Mithramycin1,5-Anhydro-2-deoxy-D-arabino-hex-1-entitol is transformed into the peracetylated 2,6-dideoxy-D-arabino compound 7 which by use of trimethylsilyl bromide is converted into the highly reactive glycosyl bromide 8. The glycosylation of both, the monoacetyl-2,6-dideoxy-D-lyxo derivatives 9 and 10, respectively, leads to the formation of the anomeric 1 → 3- as well as 1 → 4-linked disaccharides 11 or 13. In mithramycin decaacetate (2) all protons and carbon atoms could be assigned by the 2D-NMR technique. By comparison of the spectroscopic data of 2 and the peracetylated disaccharides 11 and 13 a β(1 → 3)-linkage in the B - A-disaccharide fragment of mithramycin is established.
    Notes: Ausgehend von 1,5-Anhydro-2-desoxy-D-arabino-hex-1-enitol wird die peracetylierte 2,6-Didesoxy-D-arabino-Verbindung 7 erhalten und mit Bromtrimethylsilan zu dem sehr reaktiven Glycosylbromid 8 umgesetzt. Glycosylierung der Monoacetyl-2,6-didesoxy-D-lyxo-Komponenten 9 oder 10 mit 8 ergibt die anomeren 1 → 4- und 1 → 3-verknüpften Disaccharide 11 und 13. Durch 2D-NMR-Messungen können alle Protonen und Kohlenstoffatome in Mithramycindecaacetat (2) zugeordnet werden. Vergleiche der spektroskopischen Daten von 2 mit denen der peracetylierten Disaccharide 11 und 13 beweisen das Vorliegen einer β(1 → 3)-Bindung im B - A-Disaccharidfragment des Mithramycins.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198619860503
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  • 9
    Electronic Resource
    Electronic Resource
    Konformationsanalyse, XXVIII. Konformationsanalyse von Heparin-analogen Di- und Trisacchariden mit α-L-Idopyranose-Einheiten (1988)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1988 (1988), S. 411-418 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Conformational Analysis, XXVIII. - Conformational Analysis of Heparin-Like Di- and Trisaccharides Containing α-L-Idopyranose UnitsHighfield NMR studies and HSEA calculations were performed for the synthetic heparin-like di- and trisaccharides 1-9. Comparing the measured proton-proton coupling constants and NOE values with the calculated data lead to the conclusion, that the conformation of the idopyranose unit in the oligosaccharides is in a 1C4 ⇌ 2SO equilibrium. The state of the equilibrium strongly depends on the substitution pattern. The non-sulfated structures 1 and 3 show a high 2SO proportion at the equilibrium. By substituting a sulfate group at 2′-OH position of the idopyranose unit, this unit mainly adopts the 1C4 chair conformation, see structures 5,6 and 7. Changing an N-acetyl group for a N-sulfate group at the non-reducing glucosamine unit produces a well-balanced 1C4 ⇌ 2SO equilibrium. An NH3+ group at the same glucosamine unit fixes the idopyranose unit in a slightly deformed 1C4 conformation.
    Notes: Hochfeld-NMR-Untersuchungen und HSEA-Berechnungen werden für die synthetisierten Di- und Trisaccharide 1-9 durchgeführt, die den Sequenzen des Heparins analog sind. Die gemessenen 1H-1H-Kopplungskonstanten und NOE-Effekte führen im Vergleich mit den berechneten Daten zu dem Ergebnis, daß die Idopyranose-Einheit in den Oligosacchariden ein Konformationsgleichgewicht 1C4 ⇌ 2SO einnimmt. Die Lage des Gleichgewichtes ist in hohem Maße vom jeweiligen Substitutionsmuster abhängig. Die nichtsulfatierten Strukturen 1,3 zeigen einen hohen 2SO-Anteil am Gleichgewicht. Nach Einführung einer O-Sulfatgruppe an der 2′-OH-Gruppe der Id⊙pyranose liegt diese stark bevorzugt in der 1C4-Sesselform vor wie in 5, 6 und 7. Der Austausch einer N-Acetatgruppe an der nicht-reduzierenden Glucosamin-Einheit gegen eine N-Sulfatfunktion ergibt eine ausgewogenere Gleichgewichtseinstellung 1C4 ⇌ 2SO. Eine NH3+-Gruppe an der gleichen Glucosamin-Einheit führt zu einer leicht deformierten 1C4-Konformation an der Idopyranose-Einheit.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198819880507
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  • 10
    Electronic Resource
    Electronic Resource
    Verzweigte und kettenverlängerte Zucker, XXVIII. Synthese von 6-Amino-6-desoxyhepturonsäuren (1985)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1985 (1985), S. 113-128 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Branched and Chain-extended Sugars, XXVIII.  -  Synthesis of 6-Amino-6-deoxyhepturonic AcidsThe reaction of the xylo-dialdehyde 1 with ethyl nitroacetate yields the adduct 3 which by treatment with Raney nickel in acetic anhydride leads to the chromatographically separable derivatives of 6-acetamido-6-deoxy-D-glycero-D-gluco-hepturonic acid 5 and 6-acetamido-6-deoxy-L-glycero-D-gluco-hepturonic acid 7. The configuration at C-5 of 5 and 7 was confirmed by conversion into the pyranoses 18 and 23 and analysis of their NMR spectra. The configuration at C-6 of 5 and 7 was based on the NMR data of the benzylidene derivatives 19, 20, and 24 which were accessible from 15 and 21. Stepwise deblocking reactions of compounds 5 and 7 furnish the unblocked 6-acetamido-6-deoxyheptopyranosuronic acids 27 and 30.
    Notes: Die Umsetzung des xylo-Dialdehydes 1 mit Nitroessigsäure-ethylester führt zum Addukt 3, das mit Raney-Nickel in Acetanhydrid zu den chromatographisch trennbaren Derivaten der 6-Acetamido-6-desoxy-D-glycero-D-gluco-hepturonsäure 5 und der 6-Acetamido-6-desoxy-L-glycero-D-gluco-hepturonsäure 7 führt. Die Konfigurationszuordnung an C-5 von 5 und 7 erfolgte durch Überführung in die Pyranosen 18 und 23 und Analyse ihrer NMR-Spektren. Die Zuordnung der Konfiguration an C-6 von 5 und 7 gelang durch NMR-spektroskopische Untersuchungen der über 15 und 21 darstellbaren Benzylidenverbindungen 19, 20 und 24. Durch stufenweise Entblockierung sind die freien 6-Acetamido-6-desoxyheptopyranuronsäuren 27 und 30 zugänglich.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198519850113
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