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  • Structure-activity relationship  (3)
  • Macrolide antibiotics  (2)
  • 1
    ISSN: 0947-3440
    Keywords: Antibiotics ; Soraphen ; Macrolide antibiotics ; Structure-activity relationship ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The partial synthesis of 11 analogues of soraphen A1α (1) is described. Reductive lactone ring cleavage, transformation into (17R,S)-soraphenic acid 10 and cyclization provided unnatural 17-epi-soraphen A1α (12). Removal of the phenyl-C-17 ring segment of 1 by cleavage of the lactone moiety and the C-16/C-17 bond gave the aldehyde 16 as central intermediate. After homologation of 16, introduction of a new C-17 substituent R or H, and cyclization of the lactone ring, the soraphen analogues butyl-, thienyl-, and tolylsoraphen 2b, d, e and 22b, d, e and the desphenylsoraphen 2a were obtained. The ring-contracted soraphen analogues norsoraphen 29 and 30 and desphenylnorsoraphen 31 were synthesized by introduction of a phenyl group or reduction of the intermediate aldehyde 23 followed by cyclization to the lactone. The biological activity of the soraphen analogues against Candida albicans was determined. Compared to the natural product, all analogues exhibit reduced activity. The activity of the analogues strongly depends upon the nature of the substituent R, the configuration at C-17, and the ring size.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 0947-3440
    Keywords: Antibiotics ; Soraphen ; Macrolide antibiotics ; Structure-activity relationship ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The present paper describes the chemical modification of the antifungal macrolide soraphen A1α (1) by selective removal of oxygen substituents in the south-east ring segment. In the course of this investigation two key derivatives were prepared: 4-demethyl-5-O-(4-methoxybenzyl)-4-episoraphen (6) and 3,5-dideoxy-4-oxosoraphen (22). 6 served as precursor for 4-demethoxysoraphen (19) and 4-demethoxy-5-deoxysoraphen (20). 22 was used for the deoxygenation in positions C-3, C-4 and C-5 and for the synthesis of 3,5-didesoxysoraphen (24) as well as 4-demethoxy-3,5-dideoxysoraphen (27). The comparison of the antifungicidal activity of these derivatives showed that the OH group in position C-3 is essential for the biological activity of the soraphens.
    Additional Material: 1 Tab.
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  • 3
    ISSN: 0170-2041
    Keywords: Antibiotics ; Sorangicins ; Macrolide-polyether antibiotics ; Structure-activity relationship ; Enzymes ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Antibiotics from Gliding Bacteria, L. - Chemical Modification of Sorangicin A and Structure-Activity Relationship II: Derivatives Obtained by Reduction, Oxidation and Rearrangement ReactionsThe synthesis of 38 derivatives of sorangicin A (1) with modifications of the three hydroxyl groups and the conjugated triene is described. By oxidation and reduction reactions 21-desoxy-21-oxo sorangicin (8), 21-epi-sorangicin (9) and 21-desoxysorangicins 14, 15 were obtained. With protection of the 21,22-diol the 24,25-didehydro-25-desoxysorangicin (18), 25-desoxy-25-oxosorangicins 21, 22 and 25-epi-sorangicins 23, 24 were prepared. Further, the 25-oxo derivatives 21, 22 were transformed into the oximes 25-28 and the 25-desoxy-25,25-difluoro sorangicin (31). Catalytic reduction of sorangicin A (1) gave the 37,43-dihydro derivative 35, thermolysis the cyclohexadienes 36, 37 and fluoride-induced isomerisation the 36,38,40-trienol ethers 38, 39. - Activities against Staphylococcus aureus, Escherichia coli, and in vitro inhibition of RNA polymerase of selected derivatives were examined. With most compounds a reduced biological activity was observed, some derivatives retained their activity (23-28, 31) and three were improved for certain strains (18, 21, 22) although they showed reduced enzyme inhibition activity.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
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