Crystal structures and conformational analyses of three pyranochromene derivatives.

The title compounds, C27H20O6, (I) [systematic name: methyl 7-oxo-14-phenyl-1H,7H,14H-pyrano[3,2-c:5,4-c']dichromene-14a(6bH)-carboxyl-ate], C24H22O5, (II) [systematic name: methyl 1-oxo-6-phenyl-2,3,4,12b-tetra-hydro-1H,6H-chromeno[3,4-c]chromene-6a(7H)-carboxyl-ate], and C25H23N3O4, (III) [systematic name: 6-(4-ethyl-phen-yl)-2,4-dimethyl-1,3-dioxo-2,3,4,12b-tetra-hydro-1H,6H-chromeno[4',3':4,5]pyrano[2,3-d]pyrimidine-6a(7H)-carbo-nitrile], are pyran-ochromene derivatives. The central pyran rings (B) of compounds (I) and (III) adopt half-chair conformations, whereas that of compound (II) adopts a sofa conformation. The pyran rings (A) of the chromene ring systems of compounds (II) and (III) adopt half-chair conformations, while that of compound (I) adopts a sofa conformation. The mean plane of the central pyran rings (B) make dihedral angles of 70.02 (6), 61.52 (6) and 69.12 (7)°, respectively, with the mean planes of the chromene moieties (C+A) of compounds (I), (II) and (III). The bicyclic coumarin ring system (C+A+B+E) in compound (I) is almost planar (r.m.s. deviation = 0.042 Å). The carbo-nitrile side chain in compound (III) is very nearly linear, with the C-C N angle being 176.6 (2)°. The cyclo-hexene ring (E), fused with the central pyran ring (B) in compound (II) adopts a sofa conformation. In the mol-ecular structures of compounds (II) and (III), there are C-H⋯O short contacts, which generate S(7) ring motifs. In the crystal structures of the title compounds, mol-ecules are linked by C-H⋯O hydrogen bonds, which generate mol-ecular sheets parallel to the ab plane, with R 4 (3)(28) loops in (I), inversion dimers with R 2 (2)(10) loops in (II) and chains along [010] with R 2 (2)(12) ring motifs in (III). In the crystal structures of (I) and (III), there are also C-H⋯π inter-actions present, leading to the formation of a three-dimensional framework in (II) and to sheets parallel to (101) in (III).

Crystal structure of (Z)-3-(4-meth-oxy-benzyl-idene)-2,3-di-hydro-benzo[b][1,4]thia-zepin-4(5H)-one.

In the title compound, C17H15NO2S, the two C atoms linking the S and carbonyl C atoms of the seven-membered thia-zepine ring are disordered over two sites, with occupancies of 0.511 (4) and 0.489 (4); both disorder components adopt distorted twist-boat conformations. In the crystal, N-H⋯O and C-H⋯O hydrogen bonds link inverted-related mol-ecules into dimers, incorporating R 1 (2)(6) and R 2 (2)(8) ring motifs; the acceptor carbonyl O atom is bifurcated. These dimers are further linked by C-H⋯O hydrogen bonds, forming supra-molecular tapes running along the a axis.

Highly regio- and diastereo-selective synthesis of novel tri- and tetra-cyclic perhydroquinoline architectures via an intramolecular [3 + 2] cycloaddition reaction.

A facile and efficient synthetic protocol was established for the construction of novel tri- and tetra-cyclic pyrrolo/pyrrolizinoquinoline architectures via the in situ formation of azomethine ylide followed by an intramolecular [3 + 2] cycloaddition reaction strategy. This protocol leads to the creation of two/three new rings and three/four contiguous stereocentres, in which one of them is a tetra-substituted carbon center, in a highly diastereoselective fashion with excellent yields.

Crystal structure of methyl 6-meth-oxy-11-(4-meth-oxy-phen-yl)-16-methyl-14-phenyl-8,12-dioxa-14,15-di-aza-tetra-cyclo-[8.7.0.0(2,7).0(13,17)]hepta-deca-2(7),3,5,13(17),15-penta-ene-10-carboxyl-ate.

In the title compound, C30H28N2O6, the pyran ring adopts a slightly distorted half-chair conformation and the pyrone ring adopts an envelope conformation, with the C atom bearing the carboxyl-ate group as the flap. The pyrazole ring [maximum deviation = 0.002 (2) Å] forms a dihedral angle of 13.2 (1)° with the attached benzene ring. The near-planar atoms of the pyran ring and the pyrazole ring are close to coplanar, the dihedral angles between their mean planes being 6.4 (1)°. The dihedral angle between the pyrone ring and the benzene ring of the chromene unit is 10.7 (1)°. The mol-ecular conformation is stabilized by an intra-molecular C-H⋯O hydrogen bond, which generates an S(6) ring motif. In the crystal, C-H⋯O inter-actions generate supra-molecular chains propagating in [100] and these are connected into double layers that stack along the c-axis direction by weak π-π inter-actions between pyrazole rings [centroid-centroid distance = 3.801 (1) Å].

Methyl (E)-3-(2-formyl-phen-oxy)acrylate.

In the title compound, C11H10O4, the methyl acrylate sub-stituent adopts an extended E conformation with all torsion angles close to 180°. The conformation of the keto group with respect to the olefinic double bond is typically S-trans. In the crystal, mol-ecules are linked via pairs of C-H⋯O hydrogen bonds, forming inversion dimers with an R 2 (2)(8) graph-set motif. The dimers are further linked via C-H⋯O hydrogen bonds, forming chains along [001], which enclose R 3 (2)(16) graph-set ring motifs. The keto group O atomaccepts two C-H⋯O interactions.

Methyl 1-phenyl-3-p-tolyl-1,9b-di-hydro-3H-chromeno[4,3-c]isoxazole-3a(4H)-carboxyl-ate.

In the title compound, C25H23NO4, the pyran ring of the chroman moiety has an envelope conformation with the methyl-ene C atom as the flap. The isoxazole ring has a twist conformation on the O-C bond. The dihedral angle between their mean planes is 57.87 (9)°. The attached phenyl and benzene rings are twisted away from its mean plane by 56.19 (10) and 50.57 (10)°, respectively. These two rings are normal to each other, subtending a dihedral angle of 89.2 (1)°. In the crystal, there are no classical hydrogen bonds; the mol-ecules are linked via C-H⋯π inter-actions, forming a two-dimensional network lying parallel to (10-1).

14-Meth-oxy-4,6-dimethyl-9-phenyl-8,12-dioxa-4,6-di-aza-tetra-cyclo-[8.8.0.0(2,7).0(13,18)]octa-deca-2(7),13,15,17-tetra-ene-3,5,11-trione.

The title compound, C23H20N2O6, crystallizes with two mol-ecules in the asymmetric unit in which the dihedral angles between the mean planes of the pyran and phenyl rings are 66.6 (1) and 61.9 (1) °. The fused pyrone and pyran rings each adopts a sofa conformation. In the crystal, C-H⋯O hydrogen bonds link the mol-ecules, forming a two-dimensional network parallel to [001].

Methyl 3'-benzyl-4'-(2-chloro-phen-yl)-1'-methyl-2-oxo-spiro-[indoline-3,2'-pyrrolidine]-3'-carboxyl-ate.

In the title compound, C27H25ClN2O3, the methyl-pyrrolidine ring adopts an envelope conformation with the N atom at the flap. The mean plane of the pyrrolidine ring makes dihedral angles of 82.1 (1), 84.4 (1) and 79.8 (1)°, respectively, with the adjacent benzene ring, the mean plane of the indoline ring system and the phenyl ring. The mol-ecular structure is stabilized by intra-molecular C-H⋯O hydrogen bonds. In the crystal, mol-ecules are linked into chains along [101] by N-H⋯O hydrogen bonds. C-H⋯π inter-actions are observed between the chains.

(E)-2-[(2-Formyl-phen-oxy)meth-yl]-3-(4-iso-propyl-phen-yl)acrylo-nitrile.

In the title compound, C20H19NO2, the dihedral angle between the benzene rings is 77.12 (8)°. The terminal isopropyl group is disordered over two orientations, with site occupancies of 0.720 (14) and 0.280 (14). In the crystal, mol-ecules are linked through a weak C-H⋯O inter-action, forming a zigzag chain along the c-axis direction.

8-Bromo-3-(4-ethyl-phen-yl)-1-phenyl-3,3a,4,9b-tetra-hydro-1H-chromeno[4,3-c]isoxazole-3a-carbo-nitrile.

In the title compound, C25H21BrN2O2, the fused isoxazolidine ring adopts an envelope conformation with the N atom at the flap and the mean plane of the ring makes dihedral angles of 54.37 (12) and 87.32 (13)°, respectively, with the adjacent phenyl and benzene rings. The tetra-hydro-pyran ring has a half-chair conformation. In the crystal, mol-ecules are linked into a double-column structure along the b-axis direction through weak C-H⋯O and C-H⋯π inter-actions.

Methyl 2-[(2-chloro-quinolin-3-yl)(hy-droxy)meth-yl]acrylate.

There are two independent mol-ecules (A and B) in the asymmetric unit of the title compound, C14H12ClNO3. The mean planes of the methyl ester unit (Cmeth-yl-O-C=O; r.m.s. deviation = 0.051 Šfor mol-ecule A and 0.016 Šfor mol-ecule B) and the chloro-quilonine ring system (r.m.s. deviation = 0.023 Šfor mol-ecule A and 0.014 Šfor mol-ecule B) form dihedral angles of 63.5 (1)° in mol-ecule A and 78.1 (1)° in mol-ecule B. The main difference between the two independent mol-ecules is reflected in the (H)O-C-C=C(H2) torsion angle which is -109.7 (2)° in mol-ecule A and 10.6 (2)° in mol-ecule B. An intra-molecular O-H⋯O hydrogen bond is observed in mol-ecule A. In the crystal, mol-ecules A and B are linked into pairs via bifurcated O-H⋯(N,Cl) hydrogen bonds and a weak C-H⋯O hydrogen bond links pairs of mol-ecules into chains along [100].

rac-Methyl 3-(2-meth-oxy-phen-yl)-3a,4-di-hydro-3H-chromeno[4,3-c]isoxazole-3a-carboxyl-ate.

The title compound, C19H17NO5, comprising two stereogenic C atoms of the same configuration, crystallizes in a centrosymmetric space group as a racemate. The pyran ring adopts a half-chair conformation, while the isoxazole ring adopts an envelope conformation with the C atom bonded to the meth-oxy-phenyl group as the flap. The dihedral angle between the mean plane of the pyran ring and the adjacent benzene ring is 5.86 (5)°. In the crystal, mol-ecules are linked by a weak C-H⋯O hydrogen bond, forming a chain along the a axis.

3-(4-Methoxybenzyl)-1,5-benzo-thiazepin-4(5H)-one.

In the title compound, C17H15NO2S, the thia-zepine ring adopts a slightly distorted twist-boat conformation. The dihedral angle between the mean plane of the benzo-thia-zepin ring system and the benzene ring is 65.7 (1)°. In the crystal, pairs of N-H⋯O hydrogen bonds link inversion-related mol-ecules into dimers, generating R2 (2) (8) ring motifs. These dimers are further linked by C-H⋯π and π-π inter-actions [inter-centroid distance between the benzene rings of the benzo-thia-zepine unit = 3.656 (3) Å] into a three-dimensional supra-molecular network.

(Z)-3-(3,4-Di-meth-oxy-benz-yl)-1,5-benzo-thia-zepin-4(5H)-one.

In the title compound, C18H17NO3S, the thia-zepine ring adopts a slightly distorted twist-boat conformation. The dihedral angle between the mean plane of the benzo-thia-zepin ring system and the benzene ring is 60.3 (1)°. In the crystal, mol-ecules are linked by two pairs of inversion-related N-H⋯O and C-H⋯O hydrogen bonds, generating alternating R 2 (2)(8) and R 2 (2)(6) ring motifs, respectively, in a zigzag supra-molecular chain that runs along the c axis. These chains stack along the a axis via S⋯C [3.424 (2) Å] contacts. A three-dimensional supra-molecular network is consolidated by C-H⋯π and π-π inter-actions [inter-centroid distance between di-meth-oxy-benzene rings = 3.815 (1) Å]. The crystal studied was a non-merohedral twin, with a refined value of the minor twin fraction of 0.2477 (6) .

rac-3-(4-Chloro-phen-yl)-3a,4-di-hydro-3H-chromeno[4,3-c]isoxazole-3a-carbo-nitrile.

The title compound, C17H11ClN2O2, which contains two stereogenic C atoms, crystallizes in a centrosymmetric space group as a racemate. The pyran ring and the isoxazole ring adopt sofa and twisted conformations, respectively. The dihedral angle between the benzene ring and the mean plane through the near coplanar atoms of the pyran ring is 4.17 (5)°. The mol-ecular conformation features a weak C-H⋯O contact. In the crystal, C-H⋯O hydrogen bonds link the mol-ecules, forming chains along the a-axis direction.

2-[(2-Chloro-quinolin-3-yl)(hy-droxy)meth-yl]acrylo-nitrile.

In the title compound, C13H9ClN2O, the dihedral angle between the acrylo-nitrile C=C-CN plane and the quilonine ring system is 71.3 (2)°. In the crystal, mol-ecules are linked by O-H⋯N hydrogen bonds, forming chains along [01-1]. The chains are linked into a three-dimensional network through C-H⋯N inter-actions.

(Z)-3-(3,4-Dimeth-oxy-benzyl-idene)-2,3-dihydro-1,5-benzothia-zepin-4(5H)-one.

In the title compound, C18H17NO3S, the seven-membered thia-zepine ring adopts a slightly distorted sofa conformation. The dihedral angle between the mean plane of the benzothia-zepine ring system and the benzene ring is 5.9 (1)°. The mol-ecular conformation is stabilized by an intra-molecular C-H⋯S hydrogen bond, which generates an S(7) ring motif. In the crystal, N-H⋯O and C-H⋯O hydrogen bonds link inversion-related mol-ecules into dimers, incorporating R 1 (2)(6) and R 2 (2)(8) ring motifs; the acceptor O atom is bifurcated. These dimers are further linked by C-H⋯O hydrogen bonds, forming supra-molecular tapes running along the a axis. These are connected into the three-dimensional architecture by C-H⋯π inter-actions.

(Z)-3-(2,4-Dichloro-benz-yl)-1,5-benzo-thia-zepin-4(5H)-one.

In the title compound, C16H11Cl2NOS, the seven-membered thia-zepine ring adopts a distorted twist-boat conformation. The dihedral angle between the mean plane of the benzothia-zepine ring system and the benzene ring is 78.6 (1)°. The mol-ecular conformation is stabilized by a weak intra-molecular C-H⋯Cl hydrogen bond, which generates an S(5) ring motif. In the crystal, pairs of N-H⋯O hydrogen bonds link inversion-related mol-ecules into dimers, generating R 2 (2)(8) ring motifs. The crystal packing also features alternating π-π inter-actions between benzothia-zepine benzene rings [inter-centroid distance = 3.740 (3) Å] and dichloro-benzene rings [inter-centroid distance = 3.882 (3) Å] to consolidate a three-dimensional architecture.

14-Eth-oxy-4,6-dimethyl-9-phenyl-8,12-dioxa-4,6-diaza-tetra-cyclo-[8.8.0.0(2,7).0(13,18)]octa-deca-2(7),13,15,17-tetra-ene-3,5,11-trione.

In the title compound, C23H20N2O6, the fused pyrone and pyran rings each adopt a sofa conformation. The dihedral angle between the mean planes of the pyran and phenyl rings is 61.9 (1)°. In the crystal, mol-ecules are linked by two pairs of C-H⋯O hydrogen bonds, forming dimers. These dimers are linked via a third C-H⋯O hydrogen bond, forming a two-dimensional network parallel to (10-2).

[4-(4-Meth-oxy-phen-yl)-1-methyl-3-nitro-pyrrolidin-3-yl]methanol.

In the title compound, C13H18N2O4, the dihedral angle between the benzene and pyrrolidine (all atoms) rings is 70.6 (1)°. The pyrrolidine ring adopts a half-chair conformation. In the crystal, mol-ecules form chains along the c-axis direction linked by O-H⋯N hydrogen bonds, which are then connected by C-H⋯O inter-actions, forming a sheet parallel to the bc plane.