In the indane ring system of the title molecule, C13H12O4, the hydroxy-bearing C atom is 0.134 (1) Å out of the plane of the remaining essentially planar atoms (r.m.s. deviation = 0.010 Å). In the crystal, molecules are linked into chains along the b axis by intermolecular O—H⋯O hydrogen bonds. Additional stabilization is provided by weak intermolecular C—H⋯O hydrogen bonds.
In the title compound, C8H7N3O2·H2O, the 2-methyl-5-nitro-1H-benzimidazole molecule, excluding the methyl H atoms, is approximately planar, with a maximum deviation of 0.137 (1) Å. The crystal structure is stabilized by water molecules via N—H⋯O(water), O(water)—H⋯O and O(water)—H⋯N hydrogen bonds, forming sheets parallel to the (100) plane. A short intermolecular contact between the benzene and imidazole rings, with a centroid–centroid distance of 3.6419 (10) Å, indicates a π–π interaction.
In the title molecule, C10H8N2O4, the imidazolidine ring adopts a twisted conformation. In the crystal, the molecules are linked via a pair of bifurcated intermolecular O—H⋯O hydrogen bonds, forming an inversion dimer. The dimers are further linked via N—H⋯O hydrogen bonds into a tape along the b axis.
In the title compound, C21H22O5, the mean planes of the pyran and dimethoxyphenyl rings are nearly perpendicular to one another, with the dihedral angle between them being 88.21 (8)°. The pyran ring adopts a boat conformation whereas the two fused cyclohexane rings adopt envelope conformations. In the crystal, molecules are linked into a three-dimensional network by intermolecular C—H⋯O hydrogen bonds.
The asymmetric unit of the title compound, C27H46, contains two crytallographically independent cholest-5-ene molecules (A and B). In each molecule, the three six-membered rings are all in chair conformations, while the five-membered ring is in a twist conformation. The terminal isopropyl group of molecule A has a (−)-gauche conformation, whereas that of molecule B has a (+)-gauche conformation. No significant intermolecular interactions are observed in the crystal structure.
The asymmetric unit of the title compound, C14H17N3O3·0.25H2O, comprises two independent organic molecules and a water molecule lying on a crystallographic twofold rotation axis with 50% site occupancy. In both independent molecules, the cyclohexene rings adopt envelope conformations but superposition of the two molecules shows that the flap atoms point in opposite directions. In the crystal, N—H⋯O and C—H⋯O hydrogen bonds interconnect adjacent molecules into a three-dimensional network. Weak intermolecular π–π aromatic stacking interactions [centroid–centroid distances = 3.4985 (9) and 3.6630 (9) Å] are also observed.
The asymmetric unit of the title quinoxaline compound, C10H9N3O2, contains two crystallographically independent molecules (A and B). The quinoxaline ring systems are essentially planar, with maximum deviations of 0.006 (1) and 0.017 (1) Å, respectively, for molecules A and B. In molecule A, the dihedral angle formed between the quinoxaline ring system and nitro group is 10.94 (3)° [6.31 (13)° for molecule B]. In the crystal, molecules are linked into chains propagating along : one forms zigzag chains linked by C—H⋯O hydrogen bonds, whilst the other forms ladder-like chains by way of C—H⋯N and C—H⋯O hydrogen bonds. The packing is further consolidated by weak π–π interactions [range of centroid–centroid distances = 3.5895 (7)–3.6324 (7) Å].
In the title compound, C14H18N2O, the benzimidazole grouping is close to planar, with a maximum deviation of 0.042 Å; the six-membered non-aromatic ring adopts an envelope conformation. In the crystal structure, molecules are linked into infinite sheets lying parallel to the bc plane by O—H⋯N and C—H⋯O hydrogen bonds.
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.
In the title compound, C15H8N2O, the fused ring system is approximately planar, with a maximum deviation of 0.039 (1) Å. In the crystal, weak intermolecular C—H⋯O interactions help to establish the packing.
The title compound, C27H43ClO, is a steroid derivative composed of a saturated carbon fused-ring framework with an alkyl side chain. The A and C rings have chair conformations and the B and D rings assume half-chair conformations. The cholesterol side chain is fully extended with a gauche, trans conformation of the terminal methyl groups. In the crystal structure, the molecules are aligned in an antiparallel fashion, forming alternate layers. These layers are then linked via C—H⋯O hydrogen bonds, forming a three-dimensional network.
In the title compound, C34H51NO2, the dihedral angle between the planes of the phenyl ring and the carbonyl group is 9.30 (2)°. No significant intermolecular interactions are observed in the crystal structure. The C5H11 fragment is disordered over two positions with site occupancies of 0.611 (6) and 0.389 (6).
The crystal structure of the title compound, C15H14O6·H2O, has been redetermined from single-crystal X-ray data. The structure was originally determined by Peet et al. [J. Heterocycl. Chem. (1995), 32, 33–41] but the atomic coordinates were not reported or deposited in the Cambridge Structural Database. The ethyl substituent is disordered over two sites with refined occupancies of 0.815 (6) and 0.185 (6). The indeno group is almost planar [maximum deviation 0.0922 (14) Å] and makes an angle of 68.81 (4)° with the furan ring. The fused ring molecules are assembled in pairs by intermolecular O—H⋯O hydrogen bonds. The resulting dimers are also hydrogen bonded to the water molecules, forming double-stranded chains running along the a axis.