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  • 1
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 3430-3437 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions of Coordinated Ligands, III. Synthesis of Heteroatom Chelate Complexes via the Lithium Phosphido Complex cis-Mo(CO)4(Me2PLi)2The dilithium salt cis-Mo(CO)4(Me2PLi)2 (1), obtained by deprotonation of cis-tetracarbonyl-bis(dimethylphosphine)molybdenum(0), reacts with dibromomethylstibine or dichloromethylbismutine to give the unusual complexes (CO)4Mo(PMe2-SbMe-SbMe-PMe2) (4) and (CO)4Mo(PMe2-BiMe-BiMe-PMe2) (5), respectively. Reaction of 1 with tert-butyldichlorophosphine affords in low yield a complex of a triphosphine, cis-Mo(CO)4(PMe2-PBut-PMe2) (6). While with dichlorodimethylsilane 1 affords only polymeric products of variable composition, with bis(cyclopentadienyl)titanium- or -zirconium dichloride and 1,2-dichloro-1,1,2,2-tetramethyldisilane the expected chelate complexes (CO)4Mo(PMe2-CP2EIvb-PMe2) (EIvb = Ti, Zr) (8, 9) or (CO)4Mo(PMe2-SiMe2-SiMe2-PMe2) (7), respectively, are obtained in good yields. The structure of these compounds is dicussed on the basis of their spectra.
    Notes: Das durch Deprotonierung von cis-Tetracarbonylbis(dimethylphosphin)molybdän(0) zugängliche Dilithiumsalz cis-Mo(CO)4(Me2PLi)2 (1) reagiert mit Dibrommethylstibin bzw. Dichlormethylbismutin unter Bildung der ungewöhnlichen Komplexverbindungen (CO)4Mo(PMe2-SbMe-SbMe-PMe2) (4) und (CO)4Mo(PMe2-BiMe-BiMe-PMe2) (5). Umsetzung von 1 mit tert-Butyldichlorphosphin liefert in geringer Ausbeute den Komplex eines Triphosphins, (CO)4-Mo(PMe2-PBut-PMe2) (6). Während 1 mit Dichlordimethylsilan nur polymere Produkte uneinheitlicher Zusammensetzung liefert, entstehen mit Bis(cyclopentadienyl)titan- bzw. -zir-coniumdichlorid oder 1,2-Dichlor-1,1,2,2-tetramethyldisilan die erwarteten Chelatringsysteme (CO)4Mo(PMe2-Cp2EIvb-PMe2) (EIvb = Ti, Zr) (8, 9) bzw. (CO)4 Mo(PMe2-SiMe2-SiMe2-PMe2) (7) in guten Ausbeuten. Die Struktur der Verbindungen wird auf der Basis ihrer Spektren diskutiert.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The novel iridal 10 has been isolated from rhizome extracts of Iris foetidissima. Its structure was established by spectroscopic methods and oxidative degradation. Final proof of the spirobicyclic nature of the compound - a new feature in the triterpenoid field - was afforded by the correlations observed in the 2D-HMBC- (1H-detected multiple-bond heteronuclear multiple-quantum coherence) spectrum. The possible biogenesis of this unusual compound is discussed.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The structure elucidation of four new constituents from the roots of Echinacea purpurea is described. They are shown to be cinnamoyl esters of sesquiterpene alcohols with a germacrane or a guaiane skeleton. First pharmacological results indicate immunological activities.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 2007-2013 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Cyclopentenone Derivative, XII1). - Studies on the Stereoselectivity of Intramolecular CycloadditionsChemical as well as stereochemical results of intramolecular cycloadditions in the cyclopentenone series are shown to depend very strongly on the nature of the connecting unit. With linking carbon chains as in 6 and 7, cycloaddition products 8 and 9 are formed with high but differing stereoselectivity, while the sulfur analogue 11 gives rise to a 1:1.4 mixture of steroisomers 12 and 13. Some stereoselective transformations of the cycloadducts are reported.
    Notes: Das chemische wie auch stereochemische Resultat intramolekularer Cycloadditionen in der Cyclopentenon-Reihe zeigt eine starke Abhängigkeit von der Natur des Verknüpfungsgliedes. Bei Überbrückung mit einer Kohlenstoffkette werden aus den Vorstufen 6 und 7 die Cycloadditionsprodukte 8 und 9 mit ausgezeichneter, wenn auch entgegengesetzter Stereoselektivität hervorgebracht. Einbau eines Schwefelatoms in die Kohlenstoffkette indessen führt vom Thioether-Analogon 11 zu einem 1:1.4-Gemisch der stereoisomeren Cycloaddukte 12 und 13. Einige stereoselektive Transformationen der Cycloaddukte werden mitgeteilt.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 125 (1992), S. 2159-2161 
    ISSN: 0009-2940
    Keywords: High-pressure reactions ; Cycloadditions ; Regioselectivity ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: High-pressure cycloadditions of the nonsymmetric dienophiles itaconic anhydride (6) and citraconic anhydride (7) to the homochiral cyclopentadiene 1 can be exercised with excellent regioselectivity (100%) and face selectivity
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 1356-1369 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Complexes of α,ω-PH-functional Oligophosphaalkanes H2—nR′nP—[CH2]3—PR″—[CH2]3—PR″—[CH2]3—PR′nH2—nStarting with the disecondary phosphanes R″PH—[CH2]3—PR″H (R=Me, Ph) (2a, b) α,ω-PH-functional oligophosphaalkanes H2—nR′nP—[CH2]3—PR″—[CH2]3—PR″—[CH2]3—PR′nH2—n (n = 0, 1; R′, R″=Me, Ph) (4a - d) may be obtained by two synthetic routes in good yields. Complexes 8 - 14 of composition MX2L (L=α,ω-PH-functional oligophosphaalkane; X=Cl, Br; M=Ni, Pd, Pt) are formed with these ligands by the reaction with halides of nickel, palladium, and platinum. Conductivity measurements, UV/VIS spectra as well as metathetical reactions with sodium tetraphenylborate are compatible with ionic structures [MXL]+ X-. The coordination compounds of the diprimary-ditertiary phosphanes 4c and d are obtained as a mixture of two diastereomers. According to the 31P{1H}-spectrum, the UV/VIS spectra, and conductivity measurements, a square pyramidal ligand arrangement is found in the {Ni(H2P—[CH2]3—PPh—[CH2]3—PPh—[CH2]3—PH2)Br}+ cation.
    Notes: Die α,ω-PH-funktionellen Oligophosphaalkane H2—nR′nP—[CH2]3—PR″—[CH2]3—PR″—[CH2]3—PR′nH2—n (n = 0, 1; R′, R″=Me, Ph) (4a - d) lassen sich ausgehend von den disekundären Phosphanen R″PH—[CH2]3—PR″H (R″=Me, Ph) (2a, b) nach zwei Verfahren in guten Ausbeuten darstellen. Sie bilden mit Halogeniden des Nickels, Palladiums und Platins Komplexe 8 - 14 der Zusammensetzung MX2L (L=α,ω-PH-funktionelles Oligophosphaalkan; X=Cl, Br; M=Ni, Pd, Pt). Leitfähigkeitsuntersuchungen, UV/VIS-Spektren sowie Metathesereaktionen mit Natriumtetraphenylborat weisen auf das Vorliegen ionogener Strukturen [MXL]+ X- hin. Die Koordinationsverbindungen der diprimär-ditertiären Phosphane 4c und d liegen als Gemisch zweier Diastereomere vor. 31P{1H}-NMR-Spektrum, UV/VIS-Spektren und Leitfähigkeitsmessungen sprechen für eine quadratisch-pyramidale Ligandenanordnung im {Ni(H2P—[CH2]3—PPh—[CH2]3—PPh—[CH2]3—PH2)Br}+-Kation.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 7
    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
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  • 8
    ISSN: 0947-3440
    Keywords: Preen-gland waxes ; Anser a. f. domesticus ; Cairina moschata ; Methyl-branched chain aldehydes, ketone, sec. alcohol ; Pheromones ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The insect pheromone (2R4R6R,8R)-4,6,8-trimethyl-2-undecyl formate (lardolure, 7c) and (2R,4R,6R,8R)-4,6,8-trimethyl-2-decyl formate (9-norlardolure, 7b) have been synthesized from the corresponding homologous chiral methyl-branched esters 1b and 1c, which have been obtained from the preengland wax of the domestic goose Anser a. f. domesticus. The intermediate (4R,6R,8R)-4,6,8-trimethyl-2-undecanone (4c) and (4R,6R,8R)-4,6,8-trimethyl-2-decanone (4b), the (2R)-alcohols 5c and 5b, as well as some analogous compounds, have been characterized. 9-Norlardolure (7b) shows a weak pheromone activity.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1984 (1984), S. 397-400 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: New Constituents of Levisticum officinale KochFalcarindiol (1) was identified as the antibiotic principle in roots of Levisticum officinale (Umbelliferae). In addition (Z)-ligustilide (2), angeolide (3), and five new dimers of ligustilide were isolated. Structures were elucidated by spectroscopic methods.
    Additional Material: 1 Tab.
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  • 10
    ISSN: 0170-2041
    Keywords: Myxovirescins ; [13C-Methyl]malonate ; Myxococcus virescens ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Antibiotics from Gliding Bacteria, XLI1). - On the Constitution of Myxovirescins B-T and Biogenesis of Myxovirescin AThe gliding bacteria Myxococcus virescens Mx v48 produce the myxovirescins A-T, macrocyclic lactam-lactones which differ in ring size, oxidation levels of C-121, C-20, and C-24, alkylation at C-16, and in the presence of a double bond at C26-C27. Incorporation experiments using [2,3-13C2]succinic acid as well as diethyl [13C-methyl]malonate indicate that the 16-ethyl group in myxovirescin A originates from the succinate/methyl malonate path.
    Notes: Myxobakterien des Stammes Myxococcus virescens Mx v48 produzieren einen Antibiotika-Komplex, Myxovirescine A-T, makrocyclische Lactam-Lactone, die sich in ihrer Ringgröße, den Oxidationsstufen des C-121, C-20 und des C-24, der Alkylierung an C-16 und durch eine Doppelbindung an C26-C27 unterscheiden. Markierungsversuche mit [2,3-13C2]Bernsteinsäure sowie mit [13C-Methyl]malonsäure-diethylester beweisen, daß 16-Ethyl im Myxovirescin A aus dem Succinat/Methylmalonat-Pfad stammt.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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