M. Bakthadoss

2-(1,3-Benzothia-zol-2-yl)-6-eth-oxy-phenol.

In the title compound, C15H13NO2S, the benzothiazole unit is essentially planar [maximum deviation = −0.0099 (5) Å for the S atom] and is oriented at a dihedral angle of 4.8 (5)° with respect to the benzene ring. An intramolecular O—H⋯N hydrogen bond generates an S(6) ring motif. The crystal packing is stabilized by C—H⋯π interactions.

(6bS*,14R*,14aR*)-Methyl 14-(4-methyl­phen­yl)-7-oxo-6b,6c,7,12b,14,14a-hexa­hydro-1H-pyrano[3,2-c:5,4-c′]dichromene-14a-carboxyl­ate

In the title compound, C28H22O6, the chromeno ring system is almost planar, with a dihedral angle between the mean planes of the pyran and benzene rings of 1.87 (8)°. The pyran ring bearing the methylphenyl substituent has a half-chair conformation while the other pyran ring has an envelope conformation with the tetrasubstituted C atom as the flap. The benzene ring of the chromeno ring system is inclined to the benzene ring fused to the latter pyran ring by 74.66 (9)°. These aromatic rings are inclined to the 4-methylphenyl ring by 52.67 (9) and 66.63 (10)°, respectively. In the crystal, molecules are linked via C—H⋯O hydrogen bonds, forming a two-dimensional network parallel to the bc plane.

(Z)-3-(3,4-Dimeth­oxy­benzyl­idene)-2,3-dihydro-1,5-benzothia­zepin-4(5H)-one

In the title compound, C18H17NO3S, the seven-membered thiazepine ring adopts a slightly distorted sofa conformation. The dihedral angle between the mean plane of the benzothiazepine ring system and the benzene ring is 5.9 (1)°. The molecular conformation is stabilized by an intramolecular 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 molecules 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 supramolecular tapes running along the a axis. These are connected into the three-dimensional architecture by C—H⋯π interactions.

Methyl (Z)-2-{[N-(2-formyl-phen-yl)-4-methyl-benzene-sulfonamido]-meth-yl}-3-phenyl-prop-2-enoate.

In the title compound, C25H23NO5S, the sulfonyl-bound benzene ring forms dihedral angles of 37.2 (1) and 67.0 (1)°, respectively, with the formylphenyl and phenyl rings. The molecular conformation is stabilized by an intramolecular C—H⋯π interaction. In the crystal, molecules are linked by C—H⋯O hydrogen bonds, forming a two-dimensional network in the (110) plane in which R 4 4(38) ring motifs are generated.

1-Methyl-3-(2-methyl-phen-yl)-3,3a,4,9b-tetra-hydro-1H-chromeno[4,3-c][1,2]oxazole-3a-carbonitrile.

In the title compound, C19H18N2O2, the five-membered isoxazole ring adopts an envelope conformation and the deviation of the N atom from the mean plane of the isoxazole ring is −0.3256 (11) Å. The pyran ring adopts a half-chair conformation. The isoxazole ring forms dihedral angles of 44.07 (7) and 84.23 (7)° with the pyran and methylbenzene rings, respectively. The molecular structure is stabilized by weak C—H⋯π interactions.

3-(3-Chloro­phen­yl)-1-methyl-3,3a,4,9b-tetra­hydro-1H-chromeno[4,3-c]isoxazole-3a-carbonitrile

In the title compound, C18H15ClN2O2, the five-membered isoxazole ring adopts an envelope conformation [the deviation of the N atom is 0.3154 (15) Å] and the six-membered pyran ring adopts a half-chair conformation. The mean plane through all atoms of the isoxazole ring forms dihedral angles of 47.98 (8)° with the mean plane of the chromene ring system and 75.10 (9)° with the chlorobenzene ring.

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

There are two independent molecules (A and B) in the asymmetric unit of the title compound, C14H12ClNO3. The mean planes of the methyl ester unit (Cmethyl—O—C=O; r.m.s. deviation = 0.051 Å for molecule A and 0.016 Å for molecule B) and the chloroquilonine ring system (r.m.s. deviation = 0.023 Å for molecule A and 0.014 Å for molecule B) form dihedral angles of 63.5 (1)° in molecule A and 78.1 (1)° in molecule B. The main difference between the two independent molecules is reflected in the (H)O—C—C=C(H2) torsion angle which is −109.7 (2)° in molecule A and 10.6 (2)° in molecule B. An intramolecular O—H⋯O hydrogen bond is observed in molecule A. In the crystal, molecules 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 molecules into chains along [100].

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.

N-(2-Formyl­phen­yl)-4-toluene­sulfonamide: a second monoclinic polymorph

The title compound, C14H13NO3S, (I), is a second monoclinic polymorph. The original polymorph, (II), was reported by Mahía et al. [Acta Cryst. (1999), C55, 2158–2160]. Polymorph (II) crystalllized in the space group P21/c (Z = 4), whereas the title polymorph (I) occurs in the space group P21/n (Z = 4). The dihedral angle between the two aromatic rings is 75.9 (1)° in (I) compared to 81.9 (1)° for (II). In both polymorphs, two S(6) rings are generated by intramolecular N—H⋯O and C—H⋯O hydrogen bonds, resulting in similar molecular geometries. However, the two polymorphs differ concerning their crystal packing. In (I), molecules are linked into C(8) zigzag chains along the b axis by C—H⋯O hydrogen bonds, whereas in (II) molecules are linked by C—H⋯O hydrogen bonds, forming C(7) chains along the b axis. The title polymorph is further stabilized by intermolecular C—H⋯π and π–π interactions [centroid–centroid distance = 3.814 (1) Å]. These interactions are not evident in polymorph (II).

Methyl (Z)-2-[(2,4-dioxothia-zolidin-3-yl)meth-yl]-3-(2-methyl-phen-yl)prop-2-enoate.

The C=C bond in the title compound, C15H15NO4S, has a Z configuration. The thiazolidine ring is essentially planar [maximum deviation = 0.008 (1) Å for the N atom] and is oriented at a dihedral angle of 59.1 (1)° with respect to the benzene ring. In the crystal, pairs of C—H⋯O hydrogen bonds link centrosymmetrically related molecules into dimers, generating R 2 2(18) ring motifs. The crystal packing is further stabilized by C—H⋯π and C—O⋯π [O⋯centroid = 3.412 (2) Å and C—O⋯centroid = 115.0 (1)°] interactions.