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  • 1
    Electronic Resource
    Electronic Resource
    Steroids, XLIV. Neighbouring group participation, XI. Decomposition of 2-amidomethylene-3-hydroxysteroids (1991)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1991 (1991), S. 1049-1052 
    Details
    ISSN: 0170-2041
    Keywords: Steroids ; α-Hydroxyenamides ; Neighbouring group participation ; Dienealdehydes ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: During reduction with sodium tetrahydroborate the 2-[acetyl-(alkyl)aminomethylene]-3-keto steroids 1aa, ba and 2aa - ca undergo transformation into the 2,4-diene-2-aldehydes 5a and 6, respectively. These compounds are the decomposition products of the cyclic orthoester amides of the type 4a, b, formed by NAc-6 neighbouring group participation from the 3-hydroxy derivative A, which cannot be isolated.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.1991199101181
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  • 2
    Electronic Resource
    Electronic Resource
    Steroids, XLII. Configurational analysis of 3-methoxy-16-methylestra-1,3,5(10)-trien-17-ol derivatives (1990)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1990 (1990), S. 419-422 
    Details
    ISSN: 0170-2041
    Keywords: Steroids ; Estra-1,3,5(10)-trien-17-ol derivatives ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The four possible isomers of 16-hydroxymethyl-3-methoxyestra-1,3,5(10)-trien-17-ol 5a, 6a, 7a, 8a were converted into the corresponding 16-methyl analogues 4a, 11a, 12a, 13a, which were characterized from their 1H- and 13C-NMR spectra. The results permit a configurational correlation with 16-methyl derivatives reported in the literature.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199019900181
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  • 3
    Electronic Resource
    Electronic Resource
    Steroids, LII. Configurational Analysis of 16-Methyl-19-nortestosterone Derivatives (1993)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1993 (1993), S. 923-925 
    Details
    ISSN: 0170-2041
    Keywords: Steroids ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The four possible stereoisomers of 3-methoxy-16-methyloestra-1,3,5(10)-trien-17-ol (1, 2, 3, 4) were converted into the corresponding 16-methyl-19-nortestosterone analogs (5, 6, 7, 8), which were characterized by their 1H- and 13C-NMR spectra. The coupling constants J16,17 and the characteristic 13C signals (C-12, C-17, C-18, 16-CH3) clearly confirmed the configurations at C-16 and C-17.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.1993199301146
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  • 4
    Electronic Resource
    Electronic Resource
    Vier neue Pregnanglycoside aus Gongronema latifolium (Asclepiadaceae) (1993)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1993 (1993), S. 1057-1062 
    Details
    ISSN: 0170-2041
    Keywords: 17β-Marsdenin ; Pregnane derivatives ; Biosides ; Gongronema latifolium ; Asclepiadaceae ; Steroids ; Saccharides ; Carbohydrates ; Glycosides ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Four New Pregnane Glycosides from Gongronema latifolium (Asclepiadaceae)Four so far unknown pregnane biosides have been isolated from the chloroform extract of the leaves of Gongronema latifolium Benth. et Hook. (Asclepiadaceae). From one- and twodimensional NMR experiments (NOE difference spectroscopy, ROESY, H,H-COSY, C,H-COSY, HMBC) their structures have been established as 3-O-[6-deoxy-3-O-methyl-β-D-allopyranosyl-(1→4)-β-D-canaropyranosyl]-17β-marsdenin (1a), 3-O-[6-deoxy-3-O-methyl-β-D-allopyranosyl-(1→4)-β-D-oleandropyranosyl]-17β-marsdenin (1b), 12-O-acetyl-3-O-[6-deoxy-3-O-methyl-β-D-allopyranosyl-(1→4)-β-D-canaropyranosyl]-17β-marsdenin (1c) and 11-O-acetyl-3-O-[6-deoxy-3-O-methyl-β-D-allopyranosyl-(1→4)-β-D-canaropyranosyl]-17β-marsdenin (1d).
    Additional Material: 7 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.1993199301170
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  • 5
    Electronic Resource
    Electronic Resource
    Steroids, L. Ring D Cleavage of D-Trisubstituted Steroids (1992)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1992 (1992), S. 1103-1107 
    Details
    ISSN: 0170-2041
    Keywords: Steroids ; 15-Hydroxymethylene-16-ketosteroids ; D-seco-steroids ; D-Homo-oxa-steroids ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In alkaline medium, 17β-hydroxy-15-(hydroxymethylene)androst-5-en-16-one (2a) is cleaved in two ways to give D-seco compounds. Dilute bases in protic solvents cause 1,3-dicarbonyl splitting to the 15-formyl-15,16-seco-16-oic acid 3, while the use of sodium methanolate in benzene solution gives rise to 16,17-splitting to afford the 15-formyl-16,17-seco-16,17-dioic acid 5. Both seco compounds readily undergo lactolone ring closure to give 4a and 6a, respectively. The malonaldehyde moiety of 5 is transformed in two directions: either loss of the formyl group to give 3β-hydroxy-16,17-secoandrost-5-ene-16,17-dioic acid (7a) or decarboxylation to 3β-hydroxy-16-oxo-16,17-secoandrost-5-en-17-oic acid (9) is observed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.1992199201182
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