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  • 1980-1984  (9)
  • 1
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 2055-2061 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Direct Hydroxymethylation to Branched-chain Sugars by means of a Hydroxymethyl-d1 ReagentBlocked ketoses react with the dianion 2 directly to hydroxymethylation products. Butylation products have been found as by-products. The procedure in which the yields are limited can be used favourably in special cases.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 2221-2226 
    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
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  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 2686-2693 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Determination of Relative Configurations of Spiroacetals by 1H- and 13C-NMR-SpectroscopyThe relative configuration of the spiroacetals 2, 4-7 and 9-11 is determined on the basis of solvent-depending shifts in 1H-NMR spectra and γ-effects in 13C-NMR spectra using (Z,E)-2,8-dimethyl-1,7-dioxaspiro-[5.5]undecane (ZE-2) as a key-compound.
    Notes: Die relative Konfiguration der Spiroacetale 2, 4-7 und 9-11 wird an Hand der Lösungsmittelabhängigkeit der 1H-NMR-Spektren sowie von γ-Effekten in den 13C-NMR-Spektren zugeordnet, wobei (Z,E)-2,8-Dimethyl-l,7-dioxaspiro-[5.5]undecan (ZE-2) als Schlüsselverbindung dient.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 2601-2608 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Monosaccharides Containing Nitrogen in the Ring, XXXVII. Synthesis of 1,5-Dideoxy-1,5-imino-D-galactitolThe oxime mixture 3 + 5 of the 1,6-anhydro-furanose-5-ulose 2 can be preferably hydrogenated to the 5-amino sugar 9a with galacto-configuration. Hydrolysis of the benzyloxycarbonyl compound 9b gives the sugar 7 containing nitrogen in the pyranose ring, which yields by hydrogenation 1,5-dideoxy-1,5-imino-D-galactitol (13).
    Notes: Das Oximgemisch 3 + 5 der 1,6-Anhydro-furanos-5-ulose 2 läßt sich bevorzugt zum 5-Amino-Zucker 9a der galacto-Konfiguration hydrieren. Hydrolyse der Benzyloxycarbonyl-Verbindung 9b liefert den Zucker 7 mit Stickstoff im Ring, aus dem 1,5-Didesoxy-1,5-imino-D-galactit (13) erhältlich ist.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 2616-2629 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Branched-chain Sugars, XXVI. Syntheses of Garosamine-type C-4-Methyl Branched Amino SugarsEpoxide opening of the branched-chain epoxy sugars 1 and 9 with sodium azide yields the azido sugars 2 and 4 as well as 10 and 12. Derivatives of garosamine and epigarosamine are obtainable from 2 and 10. Reaction of the branched-chain 2-enopyranoside 20 with NaN3/BF3 leads to the equilibrium mixtures 25a ⇋ 28a and 26a ⇋ 29a. The equilibrium distribution of these [3,3]-sigmatropic rearrangements, the configurational determination of the products and the conversion to amino sugars and glycosides is discussed.
    Notes: Epoxidöffnung der verzweigten Epoxyzucker 1 und 9 mit Natriumazid führt zu den Azidozuckern 2 und 4 bzw. 10 und 12. Aus 2 und 10 sind Derivate des Garosamins bzw. des Epigarosamins erhältlich. Die Reaktion des verzweigten 2-Enopyranosids 20 mit NaN3/BF3 liefert die Gleichgewichtspaare 25a ⇋ 28a und 26a ⇋ 29a. Die Gleichgewichtsverteilung dieser [3,3]-sigmatropen Umlagerungen, die Konfigurationsfestlegung der Produkte und die Umwandlung in Aminozucker und Glycoside werden diskutiert.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Branched Sugars, XXVII1).  -  Synthesis of Long Chain Saccharides by Chain Elongation with the Dianion of 1,3-Dithiane-2-methanol and Related DianionsThe dianions 3, 4, and 16, which are suitable for nucleophilic addition to aldehydo-saccharides, can be obtained by reaction of 1,3-dithiane-2-methanol, or the appropriate side chain-elongated derivatives, with 2 molar equivalents of butyllithium. With these dianions, chain elongated saccharides can be made and, in one step, various potential chiral centres may be introduced. The octose 18, the decose 21, and the undecose 22 are obtainable from 17. With 23, the elongation of the chain leads to the septose 25, the nonose 27, and the decose 28. A 2-septulose 35 and 5-deculose 37 were also made.
    Notes: Durch Umsetzung von 1,3-Dithian-2-methanol und entsprechenden an der Seitenkette verlängerten Derivaten mit 2 Moläquivalenten Butyllithium lassen sich Dianionen 3, 4 und 16 darstellen, die zur nucleophilen Addition an aldehydo-Saccharide geeignet sind. Dabei werden kettenverlängerte Saccharide erhalten, bei denen in einem Schritt mehrere vorgegebene chirale Zentren eingeführt werden können. Aus 17 sind so die Octose 18, die Decose 21 und die Undecose 22 zu erhalten. Mit 23 führt die Kettenverlängerung zur Septose 25, zur Nonose 27 und Decose 28. Auch eine 2-Septulose 35 und 5-Deculose 37 sind darstellbar.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Confomational Analysis, XXIV. - determination of the Conformations of Tri-and Tetrasaccharide Sequences of N-Glycoproteins. The problem of the (1 → 6)-glycosidic BondThe preferred solution conformations of the saccharides α-D-Man(1 → 3)-β-D-Man(1 → 4)-D-GIcNAc (1), α-D-Man(1 → 6)-β-Man(1 → 4)-D-GIcNAc (2), and α-D-Man(1 → 3)[α-D-Man(1 → 6)]lβ-D-Man(1 → 4)-D-GIcNAc3), which are known as parts of the core structure of N-glycoproteins, could be established by use of HSEA calculations (HSEA: Hard-Sphere Exo-Anomeric) with the new program GESA (= Geometry of Saccharides) in connection with 1H NMR investigations like NOE experiments, spin-lattice relaxation-time measurements and the observation of selective deshieldings. (1 → 3)- and (1 → 4)-glycosidic bonds show one strongly preferred conformation. The greater flexibility of the (1 → 6)-glycosidic bonds show one strongly preferred conformation. The greater flexibility of the (1 → 6)-glycosidic bond will be discussed in details. For the spectra analysis various 2-D techniques have been used.
    Notes: Von den Sacchariden α-D-Man(1 → 3)-β-D-Man(1 → 4)-D=-GICNAc (1), α-D-Man(1 → 6)-β-D-Man(1 → 4)-D-GIcNAc(2) und α-D-Man(1 → 3)[α-D-Man(1 → 6)]-β-D-Man(1 → 4)-D-GlcNAc(3), die als Core-Struktur in N-Glycoproteinen vorkommen, wurden durch HSEA-Berechnungen (HSEA: Hard-Sphere Exo-Anomeric) mit dem neuen GESA-Programm (GESA: Geometry of Saccharides) die bevorzugten Konformationen bestimmt. Mit Hilfe von 1H-NMR-Experimenten, nämlich NOE-Experimenten, Spin-Gitter-Relaxationszeitmessungen und der Beobachtung selektiver Entschirmungen, ließen sich diese Konformationen in Lösung bestätigen. (1 → 3)- und (1 → 4)-glycosidische Bindungen weisen eine stark bevorzugte Konformation auf. Die weitaus größere Flexibilität der (1 → 6)-glycosidischen Bindung wird besonders diskutiert. Zur Analyse der Spektren wurden verschiedene 2-D-NMR-Techniken angewandt.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Albomycins, II. - Absolute Configuration of the Deferri Form of the AlbomycinsChemical and enzymatic hydrolyses afford the degradation products of the albomycins δ2, δ1, and ε (1a - c). The absolute configuration of these degradation products or of there derivatives could be elucidated by the combination of chiroptical, gaschromatographic, and NMR (NOE) spectroscopic methods. N5-Acetyl-N5-hydroxyornithine (4) and serine (3) exist in the L-configuration, while the nucleoside contains the 6-amino-6-deoxy-4-thio-L-glycero-α-L-ido-heptofuranuronic acid. The configuration of this nucleoside could also be established by the X-ray analysis of the sulfoxide 21.
    Notes: Chemische und enzymatische Hydrolysen führen zu Abbauprodukten der Albomycine δ2, δ1 und ε (1a - c). Die absoluten Konfigurationen der Abbauprodukte oder deren Derivate werden durch Kombination chiroptischer, gaschromatographischer und NMR-spektroskopischer (NOE) Methoden abgeleitet. N5-Acetyl-N5-hydroxyornithin (4) und Serin (3) liegen in der L-Konfiguration vor, während das Nucleosid die 6-Amino-6-desoxy-4-thio-L-glycero-α-L-ido-heptofuranuronsäure enthält. Die Konfiguration des Nucleosids wird unabhängig davon durch die Röntgenstrukturanalyse des kristalline Sulfoxids 21 belegt.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1982 (1982), S. 908-913 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Cardenolides, I.  -  Ring D Cleavage of CardenolidesAction of ozone on the carda-14,20(22)-dienolides 3 and subsequent reductive work-up surprisingly does not lead to degradation of the butenolide ring but almost exclusively to cleavage of ring D with formation of the 14,15-secocardenolides 4 and 5. NaBH4 reduction of 4a or 5 stereoselectively yields 9a or, under lactone ring formation, the D-homo-15-oxacardenolide 11, respectively.
    Notes: Die Einwirkung von Ozon auf die Carda-14,20(22)-dienolide 3 und nachfolgende reduktive Aufarbeitung führt überraschenderweise nicht zum Abbau des Butenolidringes, sondern nahezu ausschließlich zur D-Ringspaltung unter Bildung der 14,15-Secocardenolide 4 und 5. Durch NaBH4-Reduktion erhält man aus 4a bzw. 5 stereoselektiv 9a bzw. unter Lactonisierung das D-Homo-15-oxacard-20(22)-enolid 11.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
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