Dimethyl 8-acetyl-2-methyl-1,2-dihydro-quinoline-2,4-dicarboxyl-ate.

In the title compound, C(16)H(17)NO(5), the six-membered N-containing ring has a half-boat form; the spiro C atom deviates by 0.34 (2) Šfrom the plane (r.m.s. deviation = 0.051 Å) defined by the N and four aromatic C atoms. Intra-molecular N-H⋯O hydrogen bonding generates an S(6) ring motif and the dihedral angle between the mean plane though the S(6) ring and that through the five-atom half-boat plane is 3.39 (2)°. In the crystal, weak inter-molecular C-H⋯O hydrogen bonds link mol-ecules into zigzag chains along [001] due to c-glide symmetry, and C-H⋯π inter-actions extend along [010].

4-[2-(Cyclo-hexa-1,4-dien-1-yl)eth-oxy]benzene-1,2-dicarbonitrile.

In the title compound, C(16)H(14)N(2)O, the dihedral angle between the aromatic rings is 70.23 (6)°. The linking chain has a zigzag conformation. In the crystal, mol-ecules are linked by weak inter-molecular C-H⋯N hydrogen bonds, forming a zigzag chain along the c axis.

17,18-Dibromo-8-methyl-4,12-ditosyl-3,4,5,6,7,8,9,10,11,12,13,14-dodeca-hydro-2H-benzo[b][1,4,7,11,15]dioxatriaza-cyclo-hepta-decine.

In the title compound, C(31)H(39)Br(2)N(3)O(6)S(2), a 17-membered aza-macrocyclic ligand containing two ether O and three aza N atoms, the three pendant aromatic rings form an 'E' shape. The dihedral angles between the central benzene ring and the side ones are 17.8 (3) and 7.4 (3)°, and the dihedral angle between the tosyl rings is 10.6 (3)°. The methyl group is disordered over two orientations, with occupancies of 0.52 (15) and 0.48 (15).

N-[(Z)-4-Meth-oxy-benzyl-idene](meth-oxy-carbon-yl)methanamine oxide.

The title compound, C(11)H(13)NO(4), contains a nitrone group, C=N-O-R, the geometry of which shows a Z configuration with near planarity (r.m.s. deviation = 0.0787 Å) around the C=N double bond. An intra-molecular C-H⋯O hydrogen bond generates an S(6) ring motif. In the crystal packing, mol-ecules are linked into R(2) (2)(12) dimers and R(2) (2)(14) rings via C-H⋯O inter-molecular hydrogen bonds.

4-Methyl-N-[(S)-1-phenyl-eth-yl]benzene-sulfonamide.

In the title compound, C(15)H(17)NO(2)S, the dihedral angle between the aromatic rings is 14.47 (8)°. The mol-ecule is bent at the N atom, with a C-SO2-NH-C torsion angle of 79.06 (13)°. In the crystal structure, the sulfonamide groups are hydrogen bonded via N-H⋯O links, forming chains of mol-ecules along the crystallographic b axis. π-π inter-actions [centroid-centroid distance = 3.81 (3) Å] also occur.

(E)-3-[(3-Bromo-phen-yl)imino-meth-yl]benzene-1,2-diol: a combined X-ray and computational structural study.

The title compound, C(13)H(10)BrNO(2), exists as an enol-imine form in the crystal and adopts an E configuration with respect to the C=N double bond. The mol-ecule is close to planar, with a dihedral angle of 6.88 (14)° between the aromatic rings. Intra-molecular O-H⋯N and O-H⋯O hydrogen bonds generate S(6) and S(5) ring motifs, respectively. The crystal structure is stabilized by inter-molecular O-H⋯O hydrogen-bond inter-actions, forming R(2) (2)(10) and R(2) (2)(20) chains along [100]. ab initio Hartree-Fock (HF), density-functional theory (DFT) and semi-empirical (AM1 and PM3) calculations and full-geometry optimizations were also performed. Although there are some discrepancies between the experimental and calculated parameters, caused presumably by the O-H⋯O hydrogen-bond inter-actions, there is an acceptable general agreement between them.

(E)-4-Meth-oxy-2-[3-(trifluoro-meth-yl)phenyl-imino-meth-yl]phenol.

The title compound, C(15)H(12)F(3)NO(2), adopts the phenol-imine tautomeric form, with the H atom attached to oxygen rather than to nitro-gen. There are two independent mol-ecules aligned nearly parallel in the asymmetric unit with their trifloramethyl groups pointing in opposite directions. The dihedral angles between the aromatic rings are 40.43 (1)° in the first mol-ecule and 36.12 (1)° in the second. Strong intra-molecular O-H⋯N hydrogen bonding generates S(6) ring motifs. Weak inter-molecular C-H⋯O hydrogen bonds link the independent mol-ecules separately into sheets normal to [010]. In addition, C-H⋯π inter-actions are also observed. The F atoms of the trifluoro-methyl groups are disordered over two sets of sites with refined site occupancies of 0.59 (2)/0.41 (2) and 0.62 (3)/0.38 (3), respectively.

(E)-3-[(4-Butyl-phen-yl)imino-meth-yl]benzene-1,2-diol.

The title compound, C(17)H(19)NO(2), exists as an enol-imine tautomer. The dihedral angle between the two benzene rings is 4.6 (2)°. The mol-ecular structure is stabilized by intramol-ecular O-H⋯O and O-H⋯N hydrogen bonds which generate S(5) and S(6) ring motifs, respectively. In the crystal, mol-ecules are linked into centrosymmetric dimers by pairs of O-H⋯O hydrogen bonds. In addition, C-H⋯π inter-actions involving both benzene rings are observed.

3-[(E)-(4-Ethyl-phen-yl)imino-meth-yl]benzene-1,2-diol.

The title compound, C(15)H(15)NO(2), adopts the enol-imine tautomeric form. The dihedral angle between the two benzene rings is 48.1 (1)°. Intra-molecular O-H⋯N and O-H⋯O hydrogen bonds generate S(6) and S(5) ring motifs, respectively. In the crystal, mol-ecules are linked into centrosymmetric R(2) (2)(10) dimers via pairs of O-H⋯O hydrogen bonds and the dimers may interact through very weak by π-π inter-actions [centroid-centroid distance = 4.150 (1) Å]. The ethyl group is disordered over two orientations, with occupancies of 0.587 (11) and 0.413 (11).