In the title compound, C20H21NO5, the dihedral angle between the mean planes through the two rings is 47.1 (8)°. The enoate group assumes an extended conformation. The hydroxyethanimine group is essentially coplanar with the benzene ring, the largest deviation from the mean plane being 0.061 (1) Å for the O atom. In the crystal, molecules are linked into cyclic centrosymmetric dimers with an R
2(6) motif via pairs of O—H⋯N hydrogen bonds. Intermolecular C—H⋯O hydrogen bonds form a C(8) chain along the b axis. The crystal packing is further stabilized by C—H⋯π interactions.
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.
The molecule of the title compound, C10H11N3O3, adopts an all-trans conformation and is approxomately planar, the largest deviation from the least-squares plane through all non-H atoms being 0.261 (1) Å. An intramolecular O—H⋯N hydrogen bond occurs. In the crystal, the molecules are packed into layers lying parallel to the ab plane by π-stacking interactions between the benzene ring of one molecule and the C—N bond of the oxime group of another molecule; the shortest intermolecular C⋯C separation within the layer is 3.412 (1) Å. The layers are connected by O—H⋯O and N—H⋯O hydrogen bonds.
In the title compound, C14H11BrN2O2, the mean planes of the two benzene rings are almost parallel to each other, making a dihedral angle of 4.09 (1)°. An intramolecular O—H⋯N hydrogen bond occurs. In the crystal, intermolecular O—H⋯N and C—H⋯O hydrogen bonds link the molecules into a chain-like supramolecular structure.
In the title compound, C20H21NO4, the two benzene rings are almost perpendicular to each other, making a dihedral angle of 86.1 (7)°. The hydroxyethanimine group is essentially coplanar with the benzene ring, the largest deviation from the mean plane of the hydroxyethanimine [C=N—OH] group being 0.011 (1) Å for the O atom. An intramolecular C—H⋯O hydrogen bond occurs. The molecules are linked into cyclic centrosymmetric R
2(6) dimers via O—H⋯N hydrogen bonds. Intermolecular C—H⋯O hydrogen bonds link the molecules, forming a C(8) chain along the a axis. The crystal packing is further stabilized by C—H⋯π interactions.
In the title compound, C18H16N2O2, the dihedral angle between the mean planes through the two benzene rings is 56.8 (6)°. The enoate group assumes an extended conformation. The hydroxyethanimine group is essentially coplanar with the benzene ring, the largest deviation from the mean plane being 0.047 (1) Å for the hydroxyimino O atom. In the crystal, the molecules are linked into cyclic centrosymmetric dimers with R
2(6) motifs via O—H⋯N hydrogen bonds.
In the title compound, C19H19NO4, the dihedral angle between the mean planes through the benzene rings is 82.18 (7)°. The C=N double bond is trans-configured. The molecules are linked into centrosymmetric dimers via pairs of O—H⋯N hydrogen bonds with the motif R
2(6). The crystal packing also features C—H⋯O interactions. The methyl group attached to one of the aromatic rings is disordered over two almost equally occupied positions [occpancy ratio = 0.51 (4):0.49 (4)].
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 title compound, C14H16N6O2, the dihedral angles formed by the mean plane of the acetohydrazide group [maximum deviation 0.0629 (12) Å] with the pyrazole and pyridine rings are 81.62 (6) and 38.38 (4)° respectively. In the crystal, molecules are connected by N—H⋯O and O—H⋯N hydrogen bonds into supramolecular chains extending parallel to the c-axis direction.
In the title compound, C17H14N2O2, the hydroxyethanimine group adopts an antiperiplanar conformation. In the crystal, molecules are linked by O—H⋯N hydrogen bonds, forming zigzag chains running along the c axis.
In the neutral, mononuclear title complex, [Ni(C4H6NO3)2(H2O)2], the Ni atom lies on a crystallographic inversion centre within a distorted octahedral N2O4 environment. Two trans-disposed anions of 3-hydroxyiminobutanoic acid occupy four equatorial sites, coordinated by the deprotonated carboxylate and protonated oxime groups and forming six-membered chelate rings, while the two axial positions are occupied by the water O atoms. The O atom of the oxime group forms an intramolecular hydrogen bond with the coordinated carboxylate O atom. The complex molecules are linked into chains along b by hydrogen bonds between the water O atom and the carboxylate O of a neighbouring molecule. The chains are linked by further hydrogen bonds into a layer structure.
The chiral title compound, C19H32O2, contains a [4.3.0]-bicyclic moiety in which the shared C—C bond presents a trans configuration and a side chain in which the C=C double bond shows an E conformation. The conformations of five- and six-membered rings are envelope (with the bridgehead atom bearing the methyl substituent as the flap) and chair, respectively, with a dihedral angle of 4.08 (17)° between the idealized planes of the rings. In the crystal, the molecules are self-assembled via classical O—H⋯O hydrogen bonds, forming chains along ; these chains are linked by weak non-classical C—H⋯O hydrogen bonds, giving a two-dimensional supramolecular structure parallel to (010). The absolute configuration was established according to the configuration of the starting material.
The title compound, C13H16N2O3, adopts an E configuration with respect to the C=N bond and an intramolecular N—H⋯N hydrogen bond results in the formation of a six-membered ring. In the crystal, intermolecular O—H⋯O hydrogen bonds link the molecules into a chain propagating along the b axis. Very weak π–π stacking interactions [centroid–centroid distance = 4.18 (2) Å] may further consolidate the packing, forming a two-dimensional supramolecular network.
In the title compound, C6H12N4OS, an intramolecular N—H⋯N hydrogen-bond is present giving rise to an S(5) ring motif. In the crystal, double-stranded chains propagating along  are formed via pairs of O—H⋯S and N—H⋯S hydrogen bonds. The chains are further stabilized by C—H⋯S interactions.
The title molecule, C11H10N2O6, has a Z conformation about the C=N bond of the oxime unit. There are significant twists from planarity throughout the molecule, the most significant being between the hydroxyimino and ester groups which are effectively orthogonal with an N—C—C—Ocarbonyl torsion angle of 91.4 (2)°. The crystal packing features oxime–benzoyl O—H⋯O contacts that lead to chains along  and C—H⋯O interactions also occur.
The title compound, C15H13ClN2O2, adopts an E conformation with respect to the azomethine C=N bond. The aniline and phenol rings are almost coplanar, making a dihedral angle of 3.33 (2)°. In the crystal, the molecules lie about inversion centers, forming dimers that are connected by intermolecular O—H⋯N hydrogen bonds, resulting in six-membered rings with graph-set motif R
2(6). In addition, there is a strong intermolecular O—H⋯N hydrogen-bonding interaction, resulting in an S(6) ring motif. Weak π–π interactions between the benzene rings [centroid–centroid distance = 3.809 (1) Å] further stabilize the crystal structure.
Each molecule of the title compound, C12H18N4O6, is located on an inversion centre at the mid-point of the central N—N bond. The azo groups C=N of the Schiff base group have an E conformation and the azo groups in the oxime C=N—O groups have a Z conformation. O–H⋯O hydrogen bonds link neighbouring molecules into infinite monolayers perpendicular to the a axis.
In the title compound, C18H16ClNO4, the dihedral angle between the mean planes through the aromatic rings is 83.8 (8)°. The hydroxyethanimine group is essentially coplanar with the ring to which it is attached [O—N—C—C torsion angle = −177.96 (13)°]. The molecules are linked into centrosymmetric R
2(6) dimers via O—H⋯N hydrogen bonds. The crystal packing is further stabilized by C—H⋯O interactions.
In the title compound, [Cu(C6H9N2O2)2], the CuII atom is located on an inversion center and has a square-planar environment. Two 2-(hydroxyimino)cyclohexan-1-one oximate monoanions chelate to the CuII atom and the Cu—N distances are 1.920 (3) and 1.930 (3) Å. There are two short intramolecular O—H⋯O hydrogen bonds between the ligands. The complex molecules stack into columns extended along the c axis, with a Cu⋯Cu distance between adjacent molecules of 3.3060 (3) Å.
The structure of the title steroid [alternative name: 3β,6β-diacetoxy-5β-methyl-19-norcholest-9(10)-ene], C31H50O4, confirms the generally accepted mechanism for the rearrangement of a cholestan-5α-ol derivative reported a century ago by Westphalen. The methyl group at position 10 of the starting material migrates to position 5 in the steroidal nucleus, while a Δ9 bond is formed, as indicated by the C=C bond length of 1.347 (4) Å. The methyl transposition leaves the 5R configuration unchanged, with the methyl oriented towards the β face. During the rearrangement, the steroidal B ring experiences a conformational distortion from chair to envelope with the C atom at position 6 as the flap. In the title structure, the isopropyl group of the side chain is disordered over two positions, with occupancies of 0.733 (10) and 0.267 (10). The carbonyl O atom in the acetyl group at C3 is also disordered with an occupancy ratio of 0.62 (4):0.38 (4).
In the title compound, C18H17NO4, the hydroxyethanimine group is essentially coplanar with the ring to which it is attached [C—C—N—O torsion angle = 179.94 (14)°]. The molecules are linked into cyclic centrosymmetric R
2(6) dimers via O—H⋯N hydrogen bonds and the crystal packing is further stabilized by C—H⋯O interactions.
In the title compound, C18H16N2O2, the hydroxyethanimine group is essentially coplanar with the ring to which it is attached (C—C—N—O torsion angle = −176.9°). Molecules are linked into cyclic centrosymmetric R
2(6) dimers via O—H⋯N hydrogen bonds.
In the title compound, [Fe(C9H13N4O4)(NH3)2], the FeIII atom, lying on a mirror plane, is coordinated by four N atoms of a triply deprotonated tetradentate N-[2-(hydroxyimino)propionyl]-N′-[2-(oxidoimino)propionyl]propane-1,3-diaminide ligand in the equatorial plane and two N atoms of two ammonia molecules at the axial positions in a distorted octahedral geometry. A short intramolecular O—H⋯O hydrogen bond between the cis-disposed oxime O atoms stabilizes the pseudo-macrocyclic configuration of the ligand. In the crystal, molecules are linked by N—H⋯O hydrogen bonds into a three-dimensional network. The ligand has a mirror-plane symmetry. One of the methylene groups of the propane bridge is disordered over two sets of sites with equal occupancy factors.
In the title complex, [Ni(C7H14N4OS)2]Cl2, the NiII ion is six-coordinated in a distorted octahedral geometry by four N atoms from the two imine and two oxime groups, and two S atoms from the thione groups. Two chloride ions complete the asymmetric unit. In the crystal, molecules are linked through N—H⋯Cl and O—H⋯Cl hydrogen bonds into an infinite chain propagating along .
In the crystal structure of the title compound, C7H14N4OS, molecules are linked through N—H⋯S and O—H⋯N hydrogen bonds and C—H⋯S interactions, forming chains propagating along [21-1].