Crystal and molecular structure of 6-0-acetylgrayanotoxin III

The crystal and molecular structure of a grayanotoxin III derivative, 6-0-acetylgrayanotoxin III is presented. The crystal is orthorhombic, space group P2 sub(l)2 sub(l)2 sub(l), with a = 15.582(3), b = 21.304(3), c = 6.339(3) angstrom, V = 2104(1) angstrom super(3), Z = 4. The structure was solved by direct methods and refined by full matrix least-squares methods to a final R = 0.047 for 1763 independent reflections with F sub(o) > 3 sigma (F sub(o)). The molecule is based on a tetracyclic structure consisting of two five-membered, one six-membered, and one seven-membered ring with various conformations.