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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Journal of chemical crystallography 29 (1999), S. 111-114 
    ISSN: 1572-8854
    Keywords: Melampolides ; sesquiterpene lactones
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract The melampolide-class sesquiterpene lactone 11βH,13-dihydro-14-hydroxy-(1,10)-cis-parthenolide, C15H22O4, 1, crystallizes in orthorhombic space group P212121 with a = 7.435(2), b = 12.678(2), c = 14.991(2) Å, V = 1413.1(8) Å3 and Z = 4. The aldehyde analog, C15H20O4·H2O, 2, crystallizes as the monohydrate in orthorhombic space group P212121 with a = 9.061(2), b = 9.295(2), c = 17.761(4) Å, V = 1495.8(9) Å3, and Z = 4. The 10-membered rings of the two molecules adopt approximate chair-boat conformations. In both compounds, the double bond at C1=C10 position of the cyclodecene ring is Z, while the C4=C5 is epoxidized with an E-configuration. The C15 methyl is β and H5 is α. The lactone ring is trans fused at the C6 and C7 positions to the 10-membered ring. The C13 methyl group has an α orientation in both molecules.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Journal of chemical crystallography 25 (1995), S. 15-17 
    ISSN: 1572-8854
    Keywords: Ethyl diglyme ; magnesium complex
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract Dibromo[1,1′-oxybix[2-ethoxyethane]-O,O′,O″]-(tetrahydrofuran-O) magnesium, C12H26O4MgBr2, crystallizes in space group Pbca witha=7.402(1),b=16.726(2),c=29.248(3) Å,V=3620.9(12) Å3,Z=8. The structure was refined toR=0.083 andR w =0.055 for 1880 observed reflections. Magnesium is octahedrally coordinated by twocis bromine atoms and four oxygen atoms, three from the meridional ethyl diglyme and one from tetrahydrofuran. The Mg−Br distances are 2.614(3)trans to thf and 2.529(3) Åtrans to the central O of the diglyme. The Br−Mg−Br angle is 97.9(1)° and the Mg−O(thf) distance is 2.196(6) Å. The O−Mg−O bite angles subtended by the diglyme are 75.3(2) and 75.7(2)°. The Mg−O(ethyl diglyme) distances are 2.127(6), 2.136(6), and 2.090(6) Å.
    Type of Medium: Electronic Resource
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