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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
    ISSN: 1572-8854
    Keywords: lamotrigine ; lamictal ; hydrogen bonded complex ; x-ray crystallography ; crystal and molecular structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract The crystal and molecular structure of lamotrigine isethionate, C9H8Cl2N5 + .HOC2H4SO3 − has been determined by direct methods. The compound crystallizes in the tetragonal space group I41/a. The isethionate moiety forms multiple hydrogen bonds to the lamotrigine nucleus, three from one isethionate, two from a symmetry related isethionate and a further two from two different symmetry related molecules. Protonation of N(2′) in the triazine ring, not observed in the native lamotrigine structure is presumably associated with the interaction of the isethionate moiety. Both rings in the lamotrigine moiety are essentially planar, with a dihedral angle of 66.08(7)° compared to 80.70° in native lamotrigine. The connecting bond length C(1)—C(6′) = 1.493(3) Å also correlates well with values in related compounds (1.480(3) Å) in the native structures.
    Type of Medium: Electronic Resource
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