Springer Online Journal Archives 1860-2000
Abstract The structure and absolute configuration (3R, 17R) of the indole alkaloid arborescidine C were determined by x-ray diffraction. The six-membered ring assumes a half-chair conformation and the seven-membered ring has a twist-like conformation. The crystal packing is characterized by intermolecular hydrogen-bonding between the hydroxyl group and nitrogen atom N4 which leads to the formation of infinite chains of molecules along the a-axis of the crystal. The absolute configurations of two related indole alkaloids, arborescidine B and arborescidine D are inferred from the experimentally determined configuration of arborescidin C molecule. A comparison of the present structure with that of a related indole alkaloid akagerine showed significant conformational and configurational differences. Crystal data: C16H19N2OBr, orthorhombic, P21212, a = 10.3376(8), b = 15.461(4), c = 9.2094(9)Å, V = 1471.9(6)Å3, Z = 4, D calc = 1.510 g cm−3, λ = 1.54178Å.
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