SuwmavyThe structures and absolute configurations of 9-0x0-9,1 l-secogorgost-5-ene-3~,ll-diol 1 1-acetate and 23-demethylgorgosterol have been determined by single crystal X-ray diffraction studies on their p-iodobenzoate derivatives.

The crystal structure of bis-(L-phenylalaninato)copper(II), CuC1sH2004N2, has been determined, and refined by three-dimensional least-squares techniques. The crystals are monoclinic, space group P21, with a= 16"710, b=5"317, c=9"509/~ and/3=98-40 °. The final R value for 1745 reflections is 0.041. The standard deviations are between 0.004 and 0.010 A, for the C, N and O atom positions. The structure closely resembles that of bis-(L-alaninato)Cu(II). The copper coordination is best described as a tetragonally distorted octahedron. The conformations of both phenylalanine molecules are similar, although there are distinct differences in detail, and such that the aromatic rings are pointed away from the metal coordination.

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Abstract. C27H33051 , monoclinic, space group P21, a = 8.088 (1), b=25.670 (3), c=6.237 (1) .~, fl=96.56 (1) °, Z=2, M=564.46, De= 1.467, D,,= 1.454 g cm -3. The compound is the p-iodobenzoate derivative ofjeunicin, an oxa-bridged cembranolide from the gorgonian Eunicea mammosa. The molecular structure and absolute configuration are determined.

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