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  • 1
    Electronic Resource
    Electronic Resource
    Voafrine A and Voafrine B, New Dimeric Indole Alkaloids from Cell Suspension Cultures of Voacanga africana Stapf (1983)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 66 (1983), S. 2525-2533 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The structures of voafrine A and voafrine B, two novel dimeric indole alkaloids isolated from Voacanga africana Stapf cell suspension cultures, were established and the medium-dependent formation of both alkaloids was investigated.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19830660818
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  • 2
    Electronic Resource
    Electronic Resource
    Synthesis and Characterization of (5′-Deoxyadenosin-5′-yl)cobalamin ( = ‘Adenosylcobalamin’) Analogues Mimicking the Transition-State Geometry of Coenzyme-B12-Dependent Rearrangements (1993)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 76 (1993), S. 2367-2383 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A convergent synthesis of the five novel analogues 1a-e of (5′-deoxyadenosin-5′-yl)cobalamin ( = ‘adenosylcobalamin’) is described. The analogues 1a-e carry oligomethylene chains (C3-C7) inserted between the central Co-atom and the 5′-O-atom of the adenosine moiety and are thought to mimick the transition-state geometry in coenzyme-B12-catalyzed rearrangement. All five analogues were characterized by NMR, UV, and FAB mass spectrometry.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19930760623
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  • 3
    Electronic Resource
    Electronic Resource
    15N-NMR Spectroscopy, 15. The Structure of Streptomycin in Solution (1980)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1980 (1980), S. 158-164 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 15N-NMR-Spektroskopie, 151). - Die Struktur von Streptomycin in LösungDie 15N-NMR-Spektren von Streptomycin und Dihydrostreptomycin wurden bei natürlichem Isotopengehalt in wäßriger Lösung bei pH 5 gemessen und verglichen. Diese Spektren zeigen eindeutig, daß die Aldehydgruppe des Streptomycins weder mit einer Guanidinogruppe noch mit der Methylaminogruppe reagiert. Die chemischen Verschiebungen der 13C-NMR-Spektren führen zu dem Schluß, daß die Aldehydgruppe als Hydrat vorliegt, das durch die Hydroxygruppe am C-3 der L-Streptose stabilisiert ist.
    Notes: The natural abundance 15N-NMR spectra of streptomycin and dihydrostreptomycin in aqueous solution at pH 5 show conclusively that the aldehyde group of streptomycin does not react with the methylamino or guanidino groups internally to form a four-ring structure. 13C-NMR data provide strong evidence that the aldehyde group forms a hydrate which is stabilized by the hydroxy group at C-3 of L-streptose.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198019800112
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  • 4
    Electronic Resource
    Electronic Resource
    Strukturnachweis von 9α-Hydroxyöstronmethylether durch zweidimensionale Protonen-FT-NMR und 13C-NMR-Spektroskopie (1982)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1982 (1982), S. 1971-1981 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Structure Elucidation of 9α-Hydroxyestrone Methyl Ether by Two-dimensional Proton FT-NMR and 13C NMR SpectroscopyThe stereochemistry of 9α-hydroxyestrone methyl ether 1 prepared by means of a photochemical key reaction is determined by a complete analysis of the proton NMR spectrum. 2D-J resolved spectra, 2D-scalar correlated spectra, and 2D-dipolar correlated spectra supply all chemical shifts and coupling constants which have been confirmed by spin simulation. Independently a study with lanthanide shift reagents (LSR) or 13C NMR analysis leads to the same stereochemical result. 1 forms an all-trans-connected ring system with ring B in the halfchair conformation.
    Notes: Die Stereochemie des mit Hilfe einer photochemischen Schlüsselreaktion dargestellten 9α-Hydroxyöstronmethylethers 1 wird durch eine vollständige Analyse des Protonen-NMR-Spektrums gesichert. Mit Hilfe von 2D-J-aufgelösten Spektren, 2D-skalar-korrelierten Spektren und 2D-dipolar-korrelierten Spektren werden sämtliche chemischen Verschiebungen und Kopplungs-konstanten bestimmt und durch Spinsimulation bestätigt. Unabhängig davon kann die Struktur sowohl durch eine Lanthaniden-Shiftreagenz-Studie als auch durch eine 13C-NMR-Analyse ermittelt werden. Es liegt ein all-trans-verknüpftes Ringsystem vor mit einer Halbsesselkonformation für den B-Ring.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198219821106
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  • 5
    Electronic Resource
    Electronic Resource
    15N-NMR Spectroscopy, 11. Stereospecifity of the Synthesis of Boc-DL-Val-DL-Val-OMe (1978)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1978 (1978), S. 1817-1822 
    Details
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 15N-NMR-Spektroskopie, 111). - Stereospezifität der Synthese von Boc-DL-Val-DL-Val-OMe36.48-MHz-15N-NMR-Spektren gestatten eine Unterscheidung der diastereomeren Dipeptide Boc-L-Val-L-Val-OH und die Boc-L-Val-D-Val-OH. Daher war es möglich das bei der Kondensation von Boc-DL-Val-OH und DL-Valinmethylester entstandene Gemisch von L-L-(D-D-) und L-D-(D-L-)Dipeptiden anhand von 15N-NMR-Spektren (bei natürlichem Isotopengehalt) zu analysieren. Die Synthese von Boc-DL-Val-DL-Val-OMe wurde unter zwölf verschiedenen Bedingungen durchgeführt.
    Notes: 36.48 MHz 15N-NMR spectra allow one to distinguish the diastereomeric dipeptides Boc-L-Val-L-Val-OH and Boc-L-Val-D-Val-OH. It is thus possible to control the ratio of L-L- (D-D-) and L-D-(D-L-)dipeptides obtained from the condensation of Boc-DL-Val-OH and DL-valine methyl ester simply by using natural abundance 15N-NMR spectra. The synthesis of Boc-DL-Val-DL-Val-OMe was carried out under twelve different experimental conditions.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.197819781114
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  • 6
    Electronic Resource
    Electronic Resource
    Use of two-dimensional NMR and molecular modelling for the structure determination of novel cyclophosphamide derivatives: Diastereomers of 1-aza-2-bis(2-chloroethyl)- amino-3-oxa-2-oxo-2-phospha-7-thia-bicyclo- [4.4.0]decane and [4.3.0]nonaneThis paper is dedicated to Professor Hans-Georg Kuball, Dept. of Physical Chemistry, University of Kaiserslautern, on the occasion of his 60th birthday. (1992)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 30 (1992), S. 1224-1240 
    Details
    ISSN: 0749-1581
    Keywords: Cyclophosphamides ; 1H NMR ; 13C NMR ; 31P coupling constants ; Molecular modelling ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: High-field NMR studies at 11.7 T of newly synthesized diastereomeric 1-aza-2-bis(2-chloroethyl)amino-3-oxa-2- oxo-2-phospha-7-thia-bicyclo[4.4.0]decanes (4, 5) and the corresponding [4.3.0]nonanes (6, 7) were carried out by employing a combination of one- and two-dimensional homo- and heteronuclear methods. Unambiguous 31P, 1H and 13C chemical shift assignments for these bicyclic derivatives of cyclophosphamide were obtained, and the spin-spin couplings involving 1H, 13C and 31P were analysed in detail to determine the stereochemistry. Particularly useful were 1H J-resolved experiments, which separated phosphorus-proton couplings from proton-proton couplings, and 1H—13C shift-correlation experiments, which resolved the carbon-phosphorus couplings and provided information on the relative signs of J(P, H) and J(P,C). In addition, extensive molecular modelling calculations using various force-field (ALCHEMY, DISCOVER) and molecular orbital methods (MNDO, AM1, PM3) were carried out, and improved parameters for cyclophosphamides were developed for ALCHEMY. The diastereomeric pairs 4, 5 and 6, 7 differ in the axial vs. equatorial orientation of the sulphur substituent on the oxazaphosphorinane ring, which is itself exclusively in a chair conformation with axial P=O for all substances.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrc.1260301212
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