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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Journal of chemical crystallography 28 (1998), S. 725-729 
    ISSN: 1572-8854
    Keywords: Synthetic steroids ; progesterone analogs ; antifertility profiles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract The title compound (C19H26N2O2) is one of a series of novel heteroatom steroidal derivatives recently prepared for testing their antifertility profiles and progesterone binding affinity. It is one of a pair of epimers differing in configuration at position 5. The X-ray analysis has uniquivocally resolved this ambiguity. The compound crystallizes in space group P212121, a = 9.257(3), b = 9.419(3), c = 19.089(5)Å, and Z = 4 and the structure was solved by direct methods. In the steroid skeleton Ring A does not exhibit the chair conformation commonly found in the steroid nucleus, being considerably strained, presumably as a consequence of the fused planar oxadiazole ring E. Rings B and C, however, are chairs and ring D is in an intermediate envelope/half-chair conformation. All rings of the steroid skeleton are trans connected.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Journal of chemical crystallography 28 (1998), S. 379-384 
    ISSN: 1572-8854
    Keywords: Synthetic steroids ; testosterone analog ; anabolic activity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract The crystal and molecular structure of 17β-hydroxy-17α-5α-androstano [2,3-C] Furazan, Furazabol (C20H24N2O2), has been determined by direct methods and refined by full matrix least squares to a final R of 0.0528 for 1927 observed reflections and 216 parameters, CuKα, λ = 1.54178 Å. The compound crystallizes with two molecules in the asymmetric unit, Z = 4, Dc = 1.131 Mg m−3 space group P21, with unit cell parameters a = 18.747(3), b = 6.346(5), c = 15.647(4) Å, β = 99.96(2)°, V = 1833.9 Å3, μ(CuKα) = 0.584 mm−1. Whilst the two independent molecules have similar overall geometry there are small differences in bond lengths, bond angles and torsion angles in rings A and D and significant conformational differences in ring A. The A ring adopts a half-chair conformation in molecule A and an intermediate between a half-chair and a sofa in molecule B. The D ring in molecule A has a 13β/14α half-chair conformation and in molecule B a conformation between an envelope and half-chair.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Computational Chemistry 10 (1989), S. 975-981 
    ISSN: 0192-8651
    Keywords: Computational Chemistry and Molecular Modeling ; Biochemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Computer Science
    Notes: The potent neuromuscular blocker, gallamine, possesses three chemically equivalent, flexible side chains, the motion of which has been proposed as important in its mode of action on the acetylcholine receptor in vivo. The flexibility of the side chains has been investigated in the present initial study by a combination of quantum mechanics and molecular dynamics on the isolated, unsolvated molecule. Net atomic charges for the gallamine molecule have been calculated using the semiempirical program MOPAC for use in the molecular dynamics simulation. The flexibility of the side chains has been shown to correlate with the range of fluctuations in torsion angles observed in the crystal structure of gallamine.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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