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  • 1
    Electronic Resource
    Electronic Resource
    Antibiotics from gliding bacteria, LXVPart LXIV: Ref.. Synthesis of soraphen analogues by substitution of the phenyl-C-17 ring segment of soraphen A1α (1995)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1995 (1995), S. 803-816 
    Details
    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
    URL: http://dx.doi.org/10.1002/jlac.1995199505118
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  • 2
    Electronic Resource
    Electronic Resource
    Antibiotics from Gliding Bacteria, LXIII. Ratjadone: A New Antifungal Metabolite from Sorangium cellulosum (1995)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1995 (1995), S. 685-688 
    Details
    ISSN: 0947-3440
    Keywords: Antibiotics ; Sorangium cellulosum ; Myxobacteria ; Antifungal agent ; Biosynthesis ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The antifungal metabolite ratjadone (1) was isolated from the myxobacterium Sorangium cellulosum, strain So ce360. Production was achieved by fermentation in the presence of the adsorber resin XAD-16, extraction and separation by RP chromatography. The structure of 1 was determined by spectroscopic methods. It is characterized by a 4-hydroxytetrahydropyran and a 5,6-dihydropyran-2-one ring which are connected by an unsaturated C11 carbon chain. The polyketide origin of 1 was proven by feeding experiments with 13C-labeled precursors and NMR spectroscopic examinations.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199519950497
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  • 3
    Electronic Resource
    Electronic Resource
    Antibiotics from Gliding Bacteria, LXXVIIIPart LXXVII: Ref.. Ripostatin A, B, and C: Isolation and Structure and Structure Elucidation of Novel Metabolites from Sorangium cellulosum (1996)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1996 (1996), S. 1657-1663 
    Details
    ISSN: 0947-3440
    Keywords: Antibiotics ; Polyketides ; Sorangium cellulosum ; RNA polymerase inhibitors ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Three closely related new metabolites named ripostatins were isolated from the myxobacterium Sorangium cellulosum and their structures elucidated by spectroscopic methods. Two of them, ripostatin A (1a, b) and B (2a), are 14-membered macrolides with an acetic acid and a phenylalkyl side chain, whereas the third metabolite ripostatin C (3a) is an acyclic derivative of ripostatin A. By application of the method of Helmchen the absolute stereochemistry could be determined as (11R,13R) for ripostatin A, 11R,13S,15R for ripostatin B and 11S for ripostatin C. The polyketide origin of A was revealed by feeding experiments with 13C-labeled precursors demonstrating the incorporation of one molecule of phenylacetic acid derived from phenylalanine, one propionate unit, and ten acetate units.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199619961026
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  • 4
    Electronic Resource
    Electronic Resource
    Antibiotics from gliding bacteria, LXIV. Isolation and structure elucidation of sorangiolides A and B, novel macrocyclic lactone carboxylic acids from Sorangium cellulosum (1995)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1995 (1995), S. 867-872 
    Details
    ISSN: 0947-3440
    Keywords: Antibiotics ; Sorangium cellulosum ; Macrolides ; Mass spectrometry ; X-ray structure analysis ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Two novel metabolites, sorangiolide A (1) and B (2), were isolated from the mother liquors and side fractions of the sorangicin A pilot-scale production. Their structures were elucidated by 2D-NMR spectroscopy and mass spectrometry as 18-membered macrolactones with a C11-carboxylic acid side chain. Sorangiolide B (2) differs from A (1) by an additional hydroxyl group at C-6 in the side chain. The absolute configuration of sorangiolide A (1) was established by X-ray structure analysis. The sorangiolides show a weak antibiotic activity against Gram-positive bacteria.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.1995199505125
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  • 5
    Electronic Resource
    Electronic Resource
    Antibiotics from Gliding Bacteria, LXXIXPart LXXVIII: Ref.[1].. - Chemical Modification of the Antifungal Macrolide Soraphen A1α: Deoxygenation in the South-East Ring Segment (1997)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1997 (1997), S. 245-252 
    Details
    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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199719970135
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  • 6
    Electronic Resource
    Electronic Resource
    Antibiotics from Gliding Bacteria, LXXX.See ref. [1] Chivosazoles A-F: Novel Antifungal and Cytotoxic Macrolides from Sorangium cellulosum (myxobacteria)Dedicated to Professor Dr. Hans Paulsen on the occasion of his 75th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1997 (1997), S. 1725-1732 
    Details
    ISSN: 0947-3440
    Keywords: Antibiotics ; Sorangium cellulosum ; Macrolides ; Chivosazole ; Biosynthesis ; Natural products ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The myxobacterial metabolites chivosazole A (1) and its variants (2-6) were discovered in Sorangium cellulosum, strain So ce12, which simultaneously provides the broad spectrum antibiotic sorangicin as well as the sorangiolides and disorazoles. The antifungal and cytotoxic chivosazoles (1-6) are novel glycosides of 6-deoxyglucopyranose derivatives and an aglycon that includes an oxazole in its 31-membered macrolide ring. The aglycon itself, chivosazole F (7), was formed by strain So ce885 and showed similar activity antibiotic and cytotoxic.The biogenetic origin of the structural elements in chivosazole F (7) was studied by feeding experiments with [1-13C]-, [1,2-13C]acetate, [methyl-13C]methionine and [1-13C]serine. Accordingly, the aglycon 7 is a polyketide assembled by condensation of nine acetate units, one serine unit and a further seven acetate units. While C-1 of serine is part of the macrolide ring, the amido to hydroxyl part of the serine together with C-1 of the adjacent N-acetyl unit form the 1,3-oxazole ring. C- and O-methyl groups are derived from methionine.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199719970814
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  • 7
    Electronic Resource
    Electronic Resource
    Antibiotika aus Gleitenden Bakterien, XXXVII. Sorangicin A, ein hochwirksames Antibiotikum mit neuartiger Makrolid-Polyether-Struktur aus Sorangium cellulosum, So ce12: Spektroskopische Strukturaufklärung, Kristall- und Lösungsstruktur (1989)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1989 (1989), S. 111-119 
    Details
    ISSN: 0170-2041
    Keywords: Macrolide-polyether antibiotic ; Sorangicin A ; Sorangium cellulosum ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Antibiotics from Gliding Bacteria, XXXVII1). - Sorangicin A, a Highly Active Antibiotic with Novel Macrolide-Polyether Structure from Sorangium cellulosum, So ce12: Spectroscopic Structure Elucidation, Crystal and Solution StructureFrom the myxobacteria Sorangium cellulosum, strain So ce12, the highly active broad spectrum antibiotic sorangicin A (1) was isolated. Its structure was elucidated predominantly by 1D- and 2D-NMR spectroscopy. The X-ray analysis of 1 was ambiguous probably due to dynamic disorder in one part of the molecule. The absolute configuration of all 15 asymmetric centers was secured with more than 99.5% probability after the Hamilton test. The dependence of the 1H-NMR spectra on water content and temperature in the sample led to a model of the structure of 1 in solution with a water bridge between the 21-hydroxy and carboxy group.
    Notes: Aus dem Myxobakterium Sorangium cellulosum, Stamm So ce12, wurde das hoch aktive Breitspektrumantibiotikum Sorangicin A (1) isoliert. Dessen Struktur wurde überwiegend durch 1D- und 2D-NMR-Spektroskopie aufgeklärt. Aufgrund einer wahrscheinlich dynamischen Fehlordnung war die Röntgenstrukturanalyse von 1 in einem Molekülteil nicht eindeutig. Die absolute Konfiguration aller 15 Asymmetriezentren konnte mit über 99.5% Wahrscheinlichkeit nach dem Hamilton-Test festgelegt werden. Die Abhängigkeit der 1H-NMR-Spektren vom Wassergehalt und von der Probentemperatur führte zu einem Modell für die Lösungsstruktur von 1 mit einer Wasserbrücke zwischen 21-Hydroxy- und Carbonsäuregruppe.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198919890124
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  • 8
    Electronic Resource
    Electronic Resource
    Antibiotika aus Gleitenden Bakterien, XXXVIII. Natürliche Strukturvarianten von Sorangicin A aus Sorangium cellulosum, So ce12 (1989)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1989 (1989), S. 213-222 
    Details
    ISSN: 0170-2041
    Keywords: Macrolide-polyether antibiotics ; Sorangicin B ; Sorangicin A variants ; Sorangium cellulosum ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Antibiotics from Gliding Bacteria, XXXVIII1). - Naturally Occurring Structural Variants of Sorangicin A Produced by Sorangium cellulosum, So ce12In addition to Sorangicin A (1) from fermentation extracts of Sorangium cellulosum a deoxygenated modification sorangicin B (2), the sorangicins A1 (3), A2 (4), and A3 (5) with isomeric triene moieties, and as isomers, in which the tetrahydrofuran ring has been opened, the sorangicins C (9), C2 (6), C3 (8), C4 (7) were isolated and their structures elucidated. The 21-O-β-D-glucosides sorangioside A (11) and B (12) and the 21-O-β-D-6′-deoxyglucosides sorangioside C (13) and C4 (14) were also found.
    Notes: Neben Sorangicin A (1) wurden aus den Fermentationsextrakten von Sorangium cellulosum eine desoxygenierte Variante Sorangicin B (2), die Sorangicine A1 (3), A2 (4) und A3 (5) mit isomerisiertem Trienteil und als Isomere, bei denen der Tetrahydrofuranring geöffnet ist, die Sorangicine C (9), C2 (6), C3 (8) und C4 (7) isoliert und in ihrer Struktur aufgeklärt. Zusätzlich wurden die 21-O-β-D-Glucoside Sorangiosid A (11) und B (12) und die 21-O-β-D-6′-Desoxyglucoside Sorangiosid C (13) und C4 (14) gefunden.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198919890142
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  • 9
    Electronic Resource
    Electronic Resource
    Antibiotics from gliding bacteria, XLIV. Ambruticins VS: New members of the antifungal ambruticin family from Sorangium cellulosum (1991)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1991 (1991), S. 941-945 
    Details
    ISSN: 0170-2041
    Keywords: Antibiotics, antifungal ; Amino acids, unusual ; Sorangium cellulosum ; Ambruticins VS ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A group of six new antifungal metabolites (ambruticins VS-1 to -5, VS-3 N-oxide) was isolated from the myxobacterium Sorangium cellulosum. They were separated by RP chromatography and identified as (5S,6R)-5-amino-6-hydroxypolyangioic acids 1b-e, 2b and methyl ester 2a by spectroscopic methods.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.1991199101161
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  • 10
    Electronic Resource
    Electronic Resource
    Antibiotics from Gliding Bacteria, LIX. Disorazoles, Highly Cytotoxic Metabolites from the Sorangicin-Producing Bacterium Sorangium Cellulosum, Strain So ce12 (1994)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1994 (1994), S. 759-773 
    Details
    ISSN: 0170-2041
    Keywords: Antibiotics ; Sorangium cellulosum ; Oxazoles ; Lactones ; Antifungal agents ; Cytotoxic agents ; Macrodiolides ; Disorazoles ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Twenty-nine disorazoles A-H (1-29) were isolated by solvent partitions and chromatographic separations from Sorangium cellulosum, strain So ce12, the producer of the sorangicin antibiotics. The disorazoles proved to be highly cytotoxic and active against fungi. The structures of the main component disorazole A1 (1) and 28 variants were elucidated by 2D-NMR and mass spectroscopy. The disorazoles are macrocyclic dilactones of two 2-pentadecyloxazol-4-carboxylic acids, which are modified in their carbon chain by variation of the position and configuration of double bonds and oxygen substituents like epoxide, hydroxyl, or methyl ether groups. In addition to these, three disorazoles are ring-enlarged by lactonization to a more distant hydroxyl group. By feeding of 13C-enriched precursors the biosynthetic origin of the carbons in disorazole A (1) was investigated. C-2 of the oxazole and the attached pentadecyl chain arise from acetate. The geminal methyl groups and the methoxyl group are derived from the methyl group of methionine.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199419940802
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