The asymmetric unit of the title compound, C30H48ClN3O, contains two molecules, A and B. In both molecules, the three cyclohexane rings in the steroid fused ring systems adopt chair conformations, while the cyclopentane rings adopt envelope and twist conformations in molecules A and B, respectively. In molecule B, the cyano group is disordered over two orientations with refined site-occupancies of 0.593 (8) and 0.407 (8). An intramolecular C—H⋯N interaction forms an S(10) ring in both molecules. In the crystal, molecules are linked by N—H⋯O, C—H⋯O and C—H⋯N interactions, resulting is chains propagating along the a-axis direction.
The title compound, C30H50O5, was isolated from the bark of Aglaia smithii. There are two independent molecules in the asymmetric unit that differ in the orientation of the isopropenyl group attached to the cyclohexane ring. The cyclohexane rings in both molecules adopt chair conformations, whereas the cyclopentane and tetrahydrofuran rings adopt envelope conformations. The independent molecules are linked into a layer parallel to (010) by O—H⋯O hydrogen bonds.
The asymmetric unit of the title compound, C27H45ClO, consists of two crystallographically independent molecules. In both molecules, the three cyclohexane rings in the steroid fused-ring systems adopt chair conformations, while the cyclopentane ring adopts a half-chair conformation in one molecule and an envelope conformation in the other. In the crystal, the molecules are linked into a two-dimensional network by weak C—H⋯O hydrogen bonds. The crystal studied is a nonmerohedral twin with a refined ratio of twin components of 0.264 (3):0.736 (3).
The title compound, C28H44O4·0.56H2O, is a co-crystal of methyl isoeichlerialactone monohydrate as the major component and methyl isoeichlerialactone as the minor component in a 0.55778 (3):0.44222 (3) ratio. The conformations of both components are identical except for that of the –COOCH3 group of the methyl propanoate side chain on the cyclohexane ring which is positionally disordered over two orientations. The molecule of methyl isoeichlerialactone has three fused rings and all rings are trans-fused. The two cyclohexane rings are in standard chair conformations and the cyclopentane ring adopts an envelope conformation. In the crystal, weak C—H⋯O interactions link methyl isoeichlerialactone molecules into screw chains along . The crystal structure is further stabilized by O—H⋯O hydrogen bonds and weak C—H⋯O interactions.
In each of the two independent indene-4-spiropentane molecules in the asymmetric unit of the title 2:1 adduct, C19H18N6·0.5C5H4OS, the cyclohexene ring adopts a half-chair conformation and the cyclopentene and cyclopentane rings adopt envelope conformations. The mean plane through the cyclohexene/cyclopentene fused system is aligned at a dihedral angle of 77.9 (1)° with respect to the mean plane through the cyclopentane ring in one molecule and 87.0 (1)° in the other. In the crystal, adjacent indene-4-spiropentane molecules are linked by N—H⋯N hydrogen bonds into a three-dimensional network. The spaces within the network are occupied by the thiophene-2-carbaldehyde molecules. The thiophene-2-carbaldehyde unit is disordered over two positions of equal occupancy. The crystal studied was found to be a non-morohedral twin with two minor twin components of 18.4 and 9.7%.
The title dammarane triterpenoid, C30H50O4, assigned the name chrysura, was isolated from an ethyl acetate extract of Walsura chrysogyne leaves (Meliaceae). It has 20S*,24S* relative stereochemistry and an oxepanone ring with two methyl groups at position 4. The two cyclohexane rings adopt chair conformations. The cyclopentane and tetrahydrofuran rings have envelope conformations; their mean planes make a dihedral angle of 13.1 (3)°, indicating that the rings are only slightly tilted with respect to each other. There is an intramolecular C—H⋯O hydrogen bond in the molecule, which forms S(6) and S(7) ring motifs. In the crystal, molecules are linked via O—H⋯O and C—H⋯O hydrogen bonds, forming chains propagating along  which stack along the b-axis direction.
The title compound, C15H20O3, a sesquiterpene lactone, was isolated from the aerial parts of Carpesium minus Hemsl. (Compositae). The molecule is composed of three rings, with the two cyclohexane rings in chair conformations and the cyclopentane ring adopting a twist conformation. The A/B ring junction is trans-fused. The absolute configuration shown has been arbitrarily assigned. In the crystal, molecules are linked into  chains by O—H⋯O hydrogen bonds.
In the title molecule, C34H53BrO4, all the cyclohexane rings adopt chair conformations, while the cyclopentane ring adopts an envelope conformation. In the crystal, weak intermolecular C—H⋯O hydrogen bonds link the molecules into corrugated sheets parallel to the ab plane.
In the title compound, C23H34O4, the C/D and D/E rings are trans fused and the A/B ring possesses an anti fusion. The two cyclohexane rings adopt a chair conformation while the cyclohexene ring exhibits a half-chair conformation. The cyclopentane ring displays an envelope conformation with the C atom bearing the methyl group as the flap. In the crystal, the molecules are linked by O—H⋯O hydrogen bonds, forming chains along the b axis.
In the decahydrophenanthrenone ring system of the title compound, C27H44O, the two cyclohexane rings adopt chair conformations, whereas the cyclohexene ring adopts an envelope conformation. The cyclopentane ring is twisted. In the crystal structure, molecules are stacked along the a axis, but no significant intermolecular interactions are observed.
The asymmetric unit of the title compound, C29H24FNO5·0.5CH3OH, contains two independent molecules and a one methanol solvent molecule. The methanol molecule is O—H⋯O hydrogen bonded to one of the independent molecules. The pyrrolidine rings in both molecules adopt half-chair conformations, while the cyclopentane rings within the indane groups are in flattened envelope conformations, with the spiro C atoms forming the flaps. The benzene rings of the indane ring systems form a dihedral angle of 35.06 (7)° in one independent molecule and 31.16 (8)° in the other. The fluoro-substituted benzene ring forms dihedral angles of 65.35 (6) and 85.87 (7)° with the indane group benzene rings in one molecule, and 72.78 (8) and 77.27 (8)° in the other. In each molecule, a weak intramolecular C—H⋯O hydrogen bond forms an S(6) ring motif. In the crystal, weak C—H⋯O, C—H⋯N and C—H⋯F hydrogen bonds link the molecules into a three-dimensional network.
The asymmetric unit of the title compound, C23H22N2O2, contains two independent molecules, A and B. The cyclohexane ring of molecule B is disordered, with occupancies for the major and minor conformers of 0.570 (9) and 0.430 (9), respectively. The cyclohexane ring adopts a boat conformation in molecule A and in the major conformer of molecule B, and a chair conformation in the minor conformer of molecule B. In both independent molecules, one of the dihydropyran rings adopts a boat conformation while the other is in a half-chair conformation. The dihedral angle between the pyrazole and phenyl rings is 16.0 (1)° in molecule A and 12.9 (1)° in molecule B. The crystal packing is stabilized by C—H⋯O and C—H⋯N intermolecular hydrogen bonds.
In the title compound, C30H22BrNO2, the cyclopentane ring of the dihydroacenaphthylene group and the pyrrolidine ring are both in envelope conformations with the spiro C atom and N atom, respectively, as the flap atom. The cyclopentane ring of the indane group adopts a half-chair conformation. A weak intramolecular C—H⋯O hydrogen bond forms an S(8) ring motif. The naphthalene ring system of the dihydroacenaphthylene group forms dihedral angles of 41.76 (6) and 42.17 (6)° with the benzene ring of the bromophenyl group and the benzene ring of the indane group, respectively. The dihedral angle between the two benzene rings is 83.92 (7)°. In the crystal, molecules are linked by weak C—H⋯O and C—H⋯N hydrogen bonds into a two-dimensional network parallel to the ac plane. Weak C—H⋯π interactions are also observed.
All atoms of the title molecule, C12H13BrClNO, except the C and H atoms of the cyclopentane methylene groups lie on a crystallographic mirror plane. The cyclopentane ring adopts an envelope conformation and an intramolecular O—H⋯N hydrogen bond is observed. In the crystal, molecules are stacked along the b axis by π–π interactions [centroid–centroid distance = 3.6424 (11) Å].
The asymmetric unit of the title compound, C30H48O2, contains two independent molecules, the main difference between them being that the isopropenyl group is rotated by approximately 180°. In each molecule, the fused six-membered rings have chair–chair–chair–chair conformations and the cyclopentane ring adopts an envelope conformation with the C atom bearing the hydroxymethyl group as the flap. All ring junctions are trans-fused. With the exception of one of the methyl groups adjacent to the C=O group, all the methyl groups are in axial positions. The isopropenyl group is equatorial and the hydroxymethyl group is in an axial orientation. In the crystal, weak C—H⋯O interactions link the molecules into chains along . Weak intramolecular C—H⋯O hydrogen bonds are also observed but the hydroxy groups are not involved in hydrogen bonds.
In the title compound, C30H26N2O3, the two pyrrolidine rings adopt twisted and envelope conformations, whereas the cyclopentane ring adopts an envelope conformation. The least-squares planes through the pyrrolidine rings form a dihedral angle of 41.72 (10)°. The molecular structure is stabilized by an intramolecular O—H⋯N hydrogen bond, which generates an S(5) ring motif. Centrosymmetrically related molecules are linked via two pairs of intermolecular C—H⋯O interactions, forming R
2(16) ring motifs. In the crystal packing, the molecules are linked into two-dimensional networks parallel to the ab plane via C—H⋯O interactions.
The title compound, C11H13N2O, was obtained by cyclocondensation of 2-aminopyridine-3-carbonitrile with cyclopentanone. The molecule is built up from two fused six-membered rings and one five-membered ring linked through a spiro C atom. Both the pyrimidine and the cyclopentane rings adopt envelope conformations. In the crystal structure, molecules are linked by intermolecular N—H⋯O hydrogen bonds.
The asymmetric unit of the title compound, C15H17NO4·H2O, contains two organic molecules with marginal differences between them and two water molecules. The chromine rings in both molecules are essentially planar, with maximum deviations of 0.012 (2) and 0.060 (2) Å. The five-membered cyclopentane rings adopt envelope conformations in both molecules. In the crystal, the components are linked by N—H⋯O, O—H⋯O and C—H⋯O hydrogen bonds, resulting in a three-dimensional network.
The title compound, C26H28N2O9·1.5H2O, the product of an acid-catalysed Wagner–Meerwein skeletal rearrangement, crystallizes as a sesquihydrate with the O atom of one of the two independent water molecules occupying a special position on a twofold axis. The organic molecule comprises a fused pentacyclic system containing two five-membered rings (cyclopentane and tetrahydrofuran) and three six-membered rings (piperidinone, tetrahydropyridine and benzene). The five-membered rings have the usual envelope conformations, and the central six-membered piperidinone and tetrahydropyridine rings adopt boat and sofa conformations, respectively. In the crystal, there are three independent O—H⋯O hydrogen bonds, which link the organic molecules and water molecules into complex two-tier layers parallel to (001). The layers are further linked into a three-dimensional framework by attractive intermolecular carbonyl–carbonyl interactions.
In the crystal structure of the title compound, C43H46NO13·0.5H2O, the molecule assumes a U-shaped conformation, the terminal benzene rings being approximately parallel and partially overlapped with each other. The molecule contains eight alicyclic and heterocyclic rings. The cyclohexane rings adopt chair conformations, the other three six-membered carbocyclic rings form a bicyclo[2.2.2]octane system with a boat conformation for each six-membered ring, the six-membered heterocyclic ring has a chair conformation and both of the five-membered rings have envelope conformations. The solvent water molecule links with the organic molecule via classic O—H⋯O and weak C—H⋯O hydrogen bonding in the crystal structure.
In the title compound, C27H20ClNO3, the two cyclopentane rings adopt envelope conformations. The pyrrolidine ring also adopts an envelope conformation (with the spiro C atom as the flap) and its least-squares plane (fitted to five atoms) makes dihedral angles of 66.50 (9), 77.36 (8) and 73.76 (8)° with the chlorobenzene ring and the two 2,3-dihydro-1H-indene ring systems, respectively. The molecular conformation is stabilized by an intramolecular C—H⋯O hydrogen bond, which generates an S(6) ring motif. In the crystal, molecules are linked by C—H⋯O hydrogen bonds into chains running parallel to the  direction.
The title molecule, C21H28O5, is composed of three six-membered rings (A/B/C) and a five-membered ring (D). Ring A adopts a 1α-sofa conformation, while rings B and C adopt chair conformations. Cyclopentane ring D adopts a 14α-envelope conformation. In the crystal, O—H⋯O hydrogen bonds lead to the formation of ribbons running along the a axis. The structure is further consolidated by C—H⋯O interactions, which link the molecules head-to-tail into ribbons along the a axis.
The asymmetric unit of the title xanthene compound, C25H30O5, contains two molecules in which the pyran ring and the dimethoxyphenyl ring are nearly perpendicular to one another [dihedral angles = 86.81 (8) and 84.45 (9)°]. One of the methoxy groups in one molecule is twisted away from the phenyl ring [C—O—C—C torsion angle = −103.40 (16)°]. The pyran ring adopts a boat conformation whereas the two fused cyclohexane rings adopt envelope conformations in both molecules. In the crystal, molecules are linked into a three-dimensional network by C—H⋯O hydrogen bonds.
The title tetronic acid derivative, C20H23ClO4, which is a spirodiclofen analogue, has two crystallographically independent molecules in the asymmetric unit (Z′ = 2). The cyclohexane rings in the respective molecules A and B adopt chair conformations [four C atoms are planar with mean deviations of 0.013 (2) and 0.001 (2) Å, and the flap positions deviate by 0.653 (4) and −0.663 (3) Å (molecule A) and 0.642 (4) and −0.643 (5) Å (molecule B) from the plane]. The furan ring makes dihedral angles of 86.9 (1) (molecule A) and 85.4 (1)° (molecule B) with the respective benzene rings.
In the title compound, C31H23NO2S, the pyrrolidine ring adopts an envelope conformation (with the spiro C atom as the flap), while the thiazolidine ring and the two cyclopentane rings adopt twisted conformations. The mean plane through the hexahydropyrrolo[1,2-c]thiazole ring [r.m.s deviation = 0.400 (1) Å] forms dihedral angles of 76.83 (4), 80.70 (5) and 79.00 (4)° with the benzene ring and the mean planes of the dihydroacenaphthylene and the dihydroindene rings, respectively. In the crystal, molecules are linked by C—H⋯O hydrogen bonds into sheets lying parallel to the bc plane. One of the ketone O atoms accepts three such bonds. Weak C—H⋯π interactions are also observed.