Santhanagopalan Purushothaman

{1'-Phenyl-1',2',5',6',7',7a'-hexa-hydro-spiro-[indeno-[1,2-b]quinoxaline-11,3'-pyrrolizin]-2'-yl}(p-tol-yl)methanone.

In the title compound, C35H29N3O, the quinoxaline and indene systems are essentially planar, with maximum deviations of 0.047 (2) and 0.032 (2) Å for C atoms, respectively. The quinoxaline system forms a dihedral angle of 4.75 (3)° with the indene system. The pyrrolizine system is folded. The substituted five-membered ring adopts an envelope conformation. In the other five-membered ring, one C atom is disordered with a site-occupancy ratio of 0.676 (12):0.324 (12). In the crystal, molecules are linked via C—H⋯O hydrogen bonds involving the bifurcated carbonyl O atom.

(E)-1-Ferrocenyl-3-[2-(2-hy-droxy-eth-oxy)phen-yl]prop-2-en-1-one.

In the title compound, [Fe(C5H5)(C16H15O3)], the cyclopentadienyl rings are in an eclipsed conformation and the benzene ring makes dihedral angles of 10.84 (9) and 12.35 (9)°, respectively, with the substituted and unsubstituted cyclopentadienyl rings. In the crystal, molecules form inversion dimers through pairs of O—H⋯O hydrogen bonds. Weak C—H⋯O hydrogen bonds are observed between the dimers.

Ethyl 27-oxo-15-oxa-2,20-diaza­hexa­cyclo­[18.6.1.01,8.02,6.09,14.021,26]hepta­cosa-9,11,13,21,23,25-hexa­ene-7-carboxyl­ate

In the title compound, C27H30N2O4, the pyrrolidine ring adopts a twisted conformation. The indoline ring system is almost perpendicular to the mean plane of the pyrrolidine ring, making a dihedral angle of 81.7 (8)°. In the crystal, molecules are linked into centrosymmetric dimers with graph-set motif R 2 2(16) via pairs of C—H⋯O hydrogen bonds. The terminal ethyl group of the ester group is disordered over two sets of sites, with a site-occupancy ratio of 0.587 (11):0.413 (11).

4'-Methyl-14',19'-dioxa-4'-aza-spiro-[acenaphthyl-ene-1,5'-tetra-cyclo-[18.4.0.0(2,6).0(8,13)]tetra-cosa-ne]-1'(24'),8',10',12',20',22'-hexa-ene-2,7'(1H)-dione.

In the title compound, C33H29NO4, the acenaphthylene ring system is essentially planar (r.m.s. deviation = 0.0290 Å). The pyrrolidine ring adopts a C-envelope conformation with a C atom displaced by 0.671 (2) Å from the mean-plane formed by the remaining ring atoms. The pyrrolidine ring is fused to acenaphthylene ring system making a dihedral angle of 88.0 (7)°. In the crystal, molecules are linked into R 2 2(9) dimers via C—H⋯N and C—H⋯O hydrogen bonds. Two C atoms act as donors to the same O atom acceptor, resulting in the formation of R 2 1(7) ring motifs. These two motifs combine to form hydrogen-bonded sheets running along the a- and b-axis directions.

24,4,8-Trioxa-21-aza-1,3,6(1,2)-tri­benzena-2(2,3)-bicyclo­[3.3.0]octa­na­cyclo­octa­phane

The crystal structure of the title compound, C26H25NO3, was determined as part of an investigation of host–guest and electron donor–acceptor complexes. The oxazole and the pyrrole rings both adopt envelope conformations. The dihedral angle between the two benzene rings directly linked to the oxazole ring is 49.5 (1)°. The crystal structure is stabilized by a C—H⋯π interaction.

(3E)-11,16-Dioxatricyclo­[15.4.0.05,10]henicosa-1(21),3,5,7,9,17,19-heptaen-2-one

The title compound, C19H18O3, crystallizes with three molecules (A, B and C) in the asymmetric unit. The carbonyl O atom shows positional disorder over two sites in molecules A and B; the site-occupancy ratios are 0.76 (3):0.24 (3) and 0.86 (3):0.14 (3), respectively. The ethylene fragments in each molecule have an E conformation, while the C—O—C—C torsion angles indicate near planarity. The dihedral angles formed by the aromatic rings are 20.0 (1), 23.7 (1) and 16.1 (1)° for molecules A, B and C, respectively. Intramolecular C—H⋯O hydrogen bonds occur in each molecule.

1-(4-{2-[(E)-3-(4-Chloro­phen­yl)-3-oxo­prop-1-en-1-yl]phen­oxy}but­yl)-1H-indole-3-carbaldehyde

In the title compound, C28H24ClNO3, the dihedral angles between the central benzene ring and the indole ring system and the chlorobenzene ring are 70.81 (5) and 78.62 (5)°, respectively. The molecular structure is stabilized by a weak intramolecular C—H⋯O interaction. In the crystal, pairs of C—H⋯O hydrogen bonds link the molecules into inversion dimers with an R 2 2(14) motif.

Ethyl 8,13-dioxa-21-aza­penta­cyclo­[18.5.1.02,7.014,19.021,25]hexa­cosa-2(7),3,5,14,16,18-hexa­ene-26-carboxyl­ate

In the title compound, C26H31NO4, the five-membered rings of the central pyrrolizine system adopt N-envelope conformations. The ethyl acetate group adopts an extended conformation. The dihedral angle between the benzene rings is 36.6 (1)°. In the crystal, C—H⋯O hydrogen bonds form a zigzag chain running along the b-axis directions. The crystal structure is futher consolidated by C—H⋯π interactions.

2,15-Dioxa-7,18,19,20,23-penta­aza­hepta­cyclo­[21.6.1.117,20.01,8.03,7.09,14.024,29]hentriaconta-9,11,13,17(31),18,24,26,28-octaen-30-one

In the title compound, C24H23N5O3, the oxindole ring system is nearly planar, with a dihedral angle between the two fused rings of 3.3 (1)°. In the fused pyrrolo-oxazole ring system, the oxazole and pyrrolidine rings adopt envelope conformations with the spiro C atom and one of the methyl-ene C atoms, respectively, as the flap atoms. In the crystal, mol-ecules are linked into a helical chain along the b axis via C-H⋯O inter-actions generating R 2 (1)(7) and R 2 (2)(8) ring motifs.

8,13,26-Trioxa-23-thia-21-aza­penta­cyclo­[18.6.0.02,7.014,19.021,25]hexa­cosa-2(7),3,5,14,16,18-hexa­ene

In the title compound, C21H23NO3S, both the thiazole and oxazolidine rings adopt twist conformations. The mean plane of the thiazole ring makes a dihedral angle of 61.02 (7)° with the oxazolidine ring mean plane, and dihedral angles of 22.72 (6) and 75.07 (6)° with the benzene rings. The benzene rings are almost perpendicular to one another, making a dihedral angle of 89.14 (6)°. There are bifurcated intramolecular C—H⋯O hydrogen bonds in the molecular structure. In the crystal, molecules are linked via C—H⋯π interactions, forming chains propagating along [100].