PREPARATION, SPECTRAL STUDIES, AND X-RAY CRYSTAL-STRUCTURES OF S,17R,20S)-3-OXO-16-HYDROXY-25-NOR-LANOSTAN-24-OIC LACTONE(II) AND 4,16-DIHYDROXY-25-NOR-3,4-SECO-LANOSTAN-3,24-DIOIC ACID DILACTONE(III)

The crystal and molecular structures of the title compounds have been determined by direct methods, and refined to a final R of 0.059 for II and 0.046 for III, Both molecules crystallize in space group P2(1)2(1 )2(1). The cell dimensions for II are a = 10.096(5), b = 11.255(3), c = 20.300(7) Angstrom; Z = 4, D-x = 1.188 g cm(-3), mu(MoK alpha) = 0.7 0 cm(-1), while the cell dimensions for III are a = 7.346(1), b = 10.4 70(3), c = 30.546(5) Angstrom; Z = 4, D-x = 1.212 g cm(-3) mu(MoK alph a) = 0.74 cm(-1). The rings of the triterpene skeletons are trans-cis- trans-cis connected. The conformations of both molecules are discussed . Also the preparation and the spectral data of (17R, 20S)-3,16-dioxo- 25-nor-lanostan-24-oic acid (V) and (17R, 4-trioxo-25-hydroxy-16,24-se co-lanostan-25-acetate (VI) are given.