organic compounds
Open access
The title compound, C31H48O7·0.04CH3COOH, is a polyoxygenated steroid obtained by selective chemical oxidation of 7-dehydrocholesteryl acetate. The asymmetric unit comprises three molecules of the steroid (Z′ = 3) and a molecule of acetic acid which has occupancy factor 0.131 (5). The geometric parameters of the independent molecules do not reveal significant differences. In one molecule, the terminal isopropyl group is disordered over two sets of sites with occupancy ratio 0.869 (5):0.131 (5). The three molecules reveal different hydrogen-bonding patterns. Each of them is involved in an intramolecular S(6) hydrogen-bonding motif, involving hydroxy groups as donor and acceptor. In the crystal, two independent molecules form dimers through hydrogen bonding between an OH donor and an acetate carbonyl acceptor, giving rise to R22(16) ring patterns. A single hydrogen bond between the OH group and a ketone carbonyl group is observed between two symmetry-independent molecules.
organic compounds
Open access
The title compound, C31H48O7, a polyoxygenated steroid, was obtained by chemical oxidation of 7-dehydrocholesteryl acetate. The molecular geometry features trans A/B and C/D junctions at the steroid core with the acetyl groups in the equatorial position and a fully extended conformation for the alkyl side chain. A chair conformation is observed for rings A and C while ring B adopts a half-chair conformation. The five-membered ring D has an envelope conformation, with the C atom bearing the methyl group at the flap. The terminal isopropyl group and one acetyl group are disordered over two sets of sites with 0.774 (8):0.226 (8) and 0.843 (7):0.157 (7) ratios, respectively. An intramolecular S(6) O—HO hydrogen-bonding motif involving a hydroxy donor and acceptor is observed. In the crystal, chains of molecules running along the b axis are formed via O—HO hydrogen bonds between hydroxy donors and carbonyl acceptors of the ordered acetyl group, giving rise to a C(14) motif. The chains are wrapped around the 21 screw axes.
organic compounds
Open access
The title compound, C20H18O6, prepared from D-mannitol by a two-step procedure, is a functionalized fused bis-tetrahydrofuran. In the central fragment, consisting of two fused tetrahydrofuran rings, one O atom and its two adjacent C atoms, a methylene and a bridgehead C atom, are disordered over two sets of sites with an occupancy ratio of 0.735 (9):0.265 (9). In the major component, the ring containing the disordered O atom is a half-chair conformation with twisted methylene and benzoate-substituted C atoms, whereas the other ring has a half-chair or T-form conformation. In the minor component, the ring with the disordered O atom has an envelope conformation, with the O atom as the flap, and the other ring has a half-chair conformation, with the O atom and the other bridgehead CH atom being twisted. The two aromatic rings are inclined to one another by 20.00 (12)°. In the crystal, adjacent molecules are linked via C—Hπ interactions, forming chains propagating along [010].