P.L.N. Lakshman

3,3,6,6-Tetra-methyl-9-phenyl-3,4,5,6-tetra-hydro-9H-xanthene-1,8(2H,7H)-dione.

In the title compound, C23H26O3, the three six-membered rings of the xanthene system are non-planar, having total puckering amplitudes, Q T, of 0.443 (2), 0.202 (2) and 0.449 (2) Å. The central ring adopts a boat conformation and the outer rings adopt sofa conformations. The crystal structure is stabilized by van der Waals interactions.

Glycinium hydrogen fumarate glycine solvate monohydrate.

In the title compound, C2H6NO2 +·C4H3O4 −·C2H5NO2·H2O, the asymmetric unit contains two glycine residues, one protonated and one in the zwitterionic form, a hydrogen fumarate anion and a water molecule. Through N—H⋯O and O—H⋯O hydrogen bonds, molecules assemble in layers parallel to the (10) plane, one layer of hydrogen fumarate anions alternating with two layers of glycine molecules. In each glycine layer, hydrogen bonds generate an R 4 4(19) graph-set motif. Further hydrogen bonds involving the water molecule and the hydrogen fumarate anions result in the formation of a three-dimensional network.

4-(4-Fluoro­phen­yl)-6-methyl­amino-5-nitro-2-phenyl-4H-pyran-3-carbo­nitrile

In the title compound, C19H14FN3O3, the central pyran ring adopts a boat conformation with the O atom and the quaternary C atom diagonally opposite displaced by 0.068 (1) and 0.075 (1) Å, respectively, above the mean plane defined by the other four ring atoms. The co-planar atoms of the pyran ring and the fluorophenyl ring are nearly perpendicular, as evidenced by the dihedral angle of 87.11 (1)°. The amine group forms an intramolecular N—H⋯O(nitro) hydrogen bond. In the crystal, molecules are linked into parallel chains along [100] by weak N—H⋯N and C—H⋯N(nitro) hydrogen bonds, generating C(8) and C(9) graph-set motifs, respectively.

Crystal structure of 2-benzyl­amino-4-(4-meth­oxy­phen­yl)-6,7,8,9-tetra­hydro-5H-cyclo­hepta­[b]pyridine-3-carbo­nitrile

The title compound comprises a 2-aminopyridine ring fused with a cycloheptane ring, which adopts a chair conformation. In the crystal, molecules are linked via pairs of N—H⋯Nnitrile hydrogen bonds, forming inversion dimers which enclose (14) ring motifs

2-Meth-oxy-4-(2-meth-oxy-phen-yl)-5,6,7,8,9,10-hexa-hydro-cyclo-octa-[b]pyridine-3-carbo-nitrile.

In the title compound, C20H22N2O2, the central pyridine ring forms a dihedral angle of 76.32 (8)° with the pseudo-axial benzene ring. The cyclooctane ring adopts a twisted boat chair conformation. In the crystal, weak intermolecular C—H⋯π interactions between inversion-related molecules result in the formation of linear double chains along the b-axis direction.

4-(2-Fluoro-phen-yl)-2-meth-oxy-5,6,7,8,9,10-hexa-hydro-cyclo-octa-[b]pyridine-3-carbo-nitrile.

In the title compound, C19H19FN2O, the cyclooctene ring adopts a twisted boat–chair conformation. The dihedral angle between the plane of the fluorophenyl substituent and that of the pyridine ring is 76.39 (8)°. The F and ortho-H atoms of the fluorobenzene ring are disordered, with occupancy factors of 0.226 (5) and 0.774 (5). In the crystal, no significant interactions are observed between the molecules beyond van der Waals contacts.

5-Amino-6-benzoyl-8-nitro-2,3-di­hydro-1H-spiro­[imidazo[1,2-a]pyridine-7,3′-indolin]-2′-one dimethyl sulfoxide monosolvate

In the title compound C21H17N5O4·C2H6OS, the central six-membered ring derived from 1,4-dihydropyridine adopts a distorted boat conformation with a small puckering amplitude of 0.127 (3) Å. The sums of bond angles around the pyridine N atom [358.7 (2)°] and the other imidazolidine N atom [60 (2)°] indicate that these atoms are in sp2 hybridization, leading to an essentially planar imidazolidine ring. The last heterocycle, an oxindole moiety, is also nearly planar with an r.m.s. deviation of 0.0185 (1) Å. The amine NH2 group forms an intramolecular hydrogen bond with the benzoyl group, giving a S(6) motif. In the crystal, N—H⋯O hydrogen bonds lead to the formation of chains along the c-axis direction. Within the chains there are further N—H⋯O and C—H⋯O hydrogen bonds enclosing R 2 2(14) ring motifs. The chains are linked via N—H⋯O and C—H⋯O hydrogen bonds involving the dimethyl sulfoxide solvent molecule which acts as both an acceptor and a donor..

5-Benzoyl-2-(1H-indol-3-yl)-4-(4-methyl­phen­yl)-4,5-dihydro­furan-3-carbonitrile

The furan ring in the title compound, C27H20N2O2, adopts a twisted conformation about the sp 3—sp 3 bond. The molecular structure is stabilized by an intramolecular C—H⋯O interaction which generates an S(6) ring motif. The crystal packing is stabilized by N—H⋯O and C—H⋯O interactions generating centrosymmetric R 2 2(18) and C(6) chain motifs, respectively. A weak C—H⋯π interaction is also observed.

(±)-trans-5-Benzoyl-2-(1H-indol-3-yl)-4-phenyl-4,5-dihydro­furan-3-carbonitrile

The furan ring in the title compound, C26H18N2O2, is twisted about the C(H)—C(H) bond. The molecular structure is stabilized by an intramolecular C—H⋯O interaction, which generates an S(6) ring motif. The presence of N—H⋯N hydrogen bonds leads to inversion dimers, which are stabilized in the crystal packing by C—H⋯O and C—H⋯π interactions, forming layers that stack along the a axis.

(±)-trans-5-Benzoyl-4-(3-bromo-phen-yl)-2-(1H-indol-3-yl)-4,5-dihydro-furan-3-carbonitrile.

The furan ring in the title compound, C26H17BrN2O2, adopts a twisted envelope conformation. The molecular structure is stabilized by an intramolecular C—H⋯O interaction which generates an S(6) ring motif. The crystal packing is stabilized by N—H⋯O and C—H⋯Br interactions, generating an R 2 2(16) ring motif and a C(12) linear chain motif, respectively. Weak C—H⋯π bonding is also observed.