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  • 1
    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.
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  • 2
    ISSN: 0947-3440
    Keywords: Isoquino[3,2-a][2]benzazepines ; B-Homoberbines ; Bischler-Napieralski reaction ; Calculations, MMX force-field ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis and Conformation of Hexahydro-isoquino[3,2-a][2]benzazepines of the B-Homoberbine TypeThe two-step synthesis of the hexahydro-isoquino[3,2-a][2]-benzazepines („B-homoberbines“) 4b-e is described. The main and some further products of the Bischler-Napieralski reaction of hydroxyamide 3c were isolated and identified. The conformation of the B-homoberbines was investigated by X-ray analysis, spectroscopic methods and dehydrogenation with mercury(II) acetate.
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  • 3
    ISSN: 0947-3440
    Keywords: Carotenoids ; Spirilloxanthin ; Didemethylspirilloxanthin ; Myxobacteria ; Polyangium fumosum ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The intense red color of the cell extracts of Polyangium fumosum, the producer of the tristhiazoline metabolite thiangazole A, is mainly caused by four new carotenoid pigments, i.e. di-O-demethylspirilloxanthin (1), its β-glucoside 2 and the glucoside fatty acid esters 3 and 4. Their structures were elucidated by IR, UV, and NMR spectroscopy and by mass spectrometry.
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  • 4
    ISSN: 0899-0042
    Keywords: cellulose ; amylose ; silica gel ; high performance liquid chromatography ; direct separations ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Direct enantiomeric separations of 17 chiral amidotetralins by means of high performance liquid chromatography were performed on stationary phases composed of tris(3,5-dimethylphenylcarbamate) derivatives of cellulose and amylose, coated on silica gel. The enantiomers of 15 out of 17 amidotetralins were resolved with a resolution of more than 1.5 by at least one of the chiral stationary phases. The stationary phases showed complementary results with regard to the separation of the amidotetralins, that is, pairs that did not separate on the cellulose-type column were well separated on the amylose-type column, and vice versa. There was no significant correlation between the chromatographic properties of the chiral stationary phases. © 1993 Wiley-Liss, Inc.
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  • 5
    ISSN: 0899-0042
    Keywords: semipreparative separation ; enantiomers ; chromatography ; tri-acetylcellulose ; melatonin ; 2-amidotetralins ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In order to obtain milligram amounts of the enantiomers of a series of compounds to be tested for binding to the melatonin binding site, a system for semipreparative enantiomeric separation was set up using tri-acetylcellulose as the chiral stationary phase. Interactions of this class of compounds with tri-acetylcellulose were examined on an analytical scale with a series of 20 compounds. Apparently, both steric and electrostatic interactions determine retention behavior on tri-acetylcellulose. Semipreparative separations were carried out for a subset of seven compounds. The purity of the first eluting enantiomer usually was around 99%, whereas the purity of the second eluting enantiomer was slightly less. The system described is easy to use and has the major advantage that a series of compounds can be separated with one technique. The purities obtained are sufficient for a first screen of their affinity. © 1994 Wiley-Liss, Inc.
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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 7 (1995), S. 82-89 
    ISSN: 0899-0042
    Keywords: CD ; conformational behaviour ; configuration ; helicity rules ; 2-aminotetralin ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The circular dichroism (CD) spectra of a series of oxygenated 2-(dipropylamino)tetralin derivatives are reported. On the basis of known absolute configurations and conformational preferences of the compounds, the validity of published correlations between the sign of the 1Lb Cotton effect and the three-dimensional structure was examined. Contrary to predictions, substitution in position 6 or 7 of the tetralin moiety did not change the sign of the 1Lb Cotton effect. An unexpected sign inversion was, however, observed in some of the compounds containing methyl substituents in the nonaromatic ring. The occurrence of this inversion was not correlated with a change in conformational behaviour and varied depending on the position and nature of the aromatic substituent. No correlations were obvious between the sign of the 1Lb Cotton effect and the absolute configuration and conformational preferences of the compounds. Therefore, at present, CD spectroscopy does not appear to be useful in assignments of the absolute configurations of 2-(dipropylamino)tetralin derivatives. © 1995 Wiley-Liss, Inc.
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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: Antibiotics from Gliding bacteria, XV. - Myxalamides A, B, C, and D, a Group o Homologous Antibiotics from Myxococcus xanthus Mx x12 (Myxobacterales)A new antibiotic complex, called myxalamides, was isolated from the cells of Myxococcus xanthus Mx x12 (GBF). After preliminary purification using florisil the myxalamides were separated by reversed-phase chromatography to give four components. The spectroscopic investigation of the main component, myxalamide B (1), revealed the structure of an alaninol amide with a highly unsaturated, branched fatty acid. The xyxalamides A (3), C(4) D(5) are amides of homologous fatty acids and alaninol.
    Notes: Aus den Zellen von Myxococcus xanthus Mx x12 (GBF) wurde ein neuer Antibiotika-Komplex, genannt Myxalamide, isoliert. Nach Vorreinigung an Florisil wurden die myxalamide durch chromatographie an einer Umkehrphase in vier Komponenten aufgetrennt. Die spektroskopische Untersuchung der Hauptkomponente, Myxalamid B (1), ergibt die Struktur eines Alaninolamids mit einer verzweigten, hohungesättigten Fettsäure. Die Myxalamide A (3), C(4) und D(5) sind Amide aus homologen Fettsäuren und Alaninol.
    Additional Material: 5 Ill.
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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: Antibiotics from Gliding Bacteria, XXIV. - Corallopyronin A, B, and C - Three Novel Antibiotics from Corallococcus coralloides, Cc c127 (Myxobacterales)Three new antibiotics, corallopyronin A (1), B (2), and C (4) have been isolated from the culture broth of Corallococcus coralloides, strain Cc c127 (DSM 2550), by phase distribution and chromatography. The corallopyronins are closely related to myxopyronin A (5) and B (6), two homologous 3-acyl-4-hydroxy-α-pyrons with an α,β-unsaturated methyl carbamate function. Structurally the new antibiotics differ from the myxopyronins in an elongated 3-acyl side chain with two additional double bonds and one hydroxy function in corallopyronin A (1) and B (2) or an 3-acyl residue with a tetrahydrofuran ring in the component C (4).
    Notes: Aus dem Kulturmedium von Corallococcus coralloides, Stamm Cc c127 (DSM 2550), wurden drei neue Antibiotika, die Corallopyronine A (1), B (2) und C (4) durch Phasenverteilung und Chromatographie isoliert. Die Corallopyronine sind mit den Myxopyroninen A (5) und B (6), zwei homologen 3-Acyl-4-hydroxy-α-pyronen mit α,β-ungesättigter Methylcarbamatfunktion, nahe verwandt. Die neuen Antibiotika unterscheiden sich strukturell von den Myxopyroninen durch einen verlängerten 3-Acylrest mit zwei zusätzlichen Doppelbindungen und einer Hydroxyfunktion in Corallopyronin A (1) und B (2) oder durch einen 3-Acylrest mit einem Tetrahydrofuranring in der Komponente C (4).
    Additional Material: 3 Ill.
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  • 9
    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.
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  • 10
    ISSN: 0170-2041
    Keywords: Sorangicin ; Biosynthesis ; [13C]Acetates ; [13C]Methionine ; [13C]Carbonate ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Antibiotics from Gliding Bacteria, XXXIX1). - Biosynthesis of Sorangicin A in Sorangium cellulosum, So ce12The biogenesis of sorangicin A (1) was studied by feeding experiments with single and doubly labeled [13C]acetates as well as sodium [13C]hydrogencarbonate and [methyl-13C]methionine. Accordingly, 1 is assembled by linear condensation of twenty acetate units onto a malonate starter unit, which is completely preserved in 1. The carboxy group of the malonyl-CoA ester, identical with C-1 in 1, is labeled by [13C]carbonate or by carbon originating from [1-13C]acetate. The four methyl groups in 1 are derived from methionine.
    Notes: Die Biogenese von Sorangicin A (1) wurde durch Verfüttern von einfach und doppelt 13C-markierten Acetaten sowie von [13C]Natriumhydrogencarbonat und [Methyl-13C]Methionin untersucht. Demnach wird 1 durch lineare Kondensation von zwanzig Acetateinheiten an einen Malonatstarter aufgebaut, der vollständig in 1 enthalten ist. Die Carboxylgruppe des Malonyl-Co-A-esters, identisch mit C-1 in 1, wird durch [13C]Carbonat oder durch Kohlenstoff aus [1-13C]Acetat markiert. Die vier Methylgruppen in 1 stammen aus Methionin.
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