Mohammad Asad

9-(7-Fluoro-4-oxo-4H-chromen-3-yl)-3,3,6,6-tetra-methyl-2,3,4,5,6,7,8,9-octa-hydro-1H-xanthene-1,8-dione.

In the title compound, C26H25FO5, the terminal cyclohexane rings of the xanthene ring system adopt half-boat conformations. The 4H-chromene ring make a dihedral angle of 87.94 (5)° with the xanthene ring system and its carbonyl O atom lies above the xanthene O atom. In the crystal, molecules are linked into ribbons propagating along the a-axis direction by C—H⋯O hydrogen bonds. Aromatic π–π stacking interactions [centroid–centroid distance = 3.7367 (12) Å] also occur.

Synthesis and Antimycobacterial Activity of Highly Functionalised Pyrrolothiazole Derivatives

A series of twelve pyrralothiazoles was synthesized using [3+2]- cycloaddition reactions. The synthesized compounds were screened for their antimycobacterial activity against M. tuberculosis H37Rv and INH resistant M. tuberculosis strains using agar dilution method, four of them showed good activity with MIC of less than 1μM. Compound (4d) was found to be the most active with MIC of 0.231 μM and 4.372 μM respectively.

7-Fluoro-4-oxochromene-3-carbaldehyde

In the title compound, C10H5FO3, the chromenone ring is essentially planar, with a maximum deviation of 0.039 (1) Å. The dihedral angle between the fluoro-subsituted benzene ring and the pyran ring is 1.92 (4)°. In the crystal, molecules are connected via weak intermolecular C—H⋯O hydrogen bonds, forming supramolecular ribbons along the b axis. These ribbons are stacked down the a axis.

2-[(E)-(2,4-Dichloro-benzyl-idene)amino]-isoindoline-1,3-dione.

In the title compound, C15H8Cl2N2O2, the molecule adopts an E configuration about the central C=N double bond. The isoindoline ring is essentially planar, with a maximum deviation of 0.019 (2) Å. The dihedral angle between the isoindoline ring and the dichloro-substituted benzene ring is 6.54 (9)°. An intramolecular C—H⋯O hydrogen bond occurs. A short Cl⋯Cl contact of 3.4027 (9) Å is present in the crystal structure. The crystal packing is further stabilized by weak C—H⋯π interactions.

3-[5-(2,4-Dichloro-phen-yl)-1-phenyl-4,5-dihydro-1H-pyrazol-3-yl]-4-hy-droxy-2H-chromen-2-one.

In the title compound, C(24)H(16)Cl(2)N(2)O(3), the chromene ring system is almost planar, with a maximum deviation of 0.042 (1) Å. It makes dihedral angles of 3.72 (6), 73.37 (5) and 12.00 (5)° with the dihydro-pyrazole, benzene and phenyl rings, respectively. An intra-molecular O-H⋯N hydrogen bond forms an S(6) ring motif. In the crystal, mol-ecules are linked via C-H⋯O inter-actions, forming an infinite chain along the a axis. The crystal packing is further stabilized by a π-π stacking inter-action [centroid-centroid distance = 3.5471 (7) Å] and a Cl⋯Cl short contact [Cl⋯Cl = 3.214 (1) Å].

3-Methyl-4-[(E)-3-thien-ylmethyl-idene-amino]-1H-1,2,4-triazole-5(4H)-thione.

The asymmetric unit of the title compound, C8H8N4S2, contains two crystallographically independent molecules. The thiophene ring of one molecule is disordered over two positions with refined site occupancies of 0.6375 (19) and 0.3625 (19). One molecule is almost planar and the other one is twisted, the dihedral angles between the thiophene and triazole rings being 7.28 (7) and 48.9 (2)° [48.5 (4)° for the minor component], respectively. An intramolecular C—H⋯S hydrogen bond stabilizes the molecular conformation of the planar molecule. In the crystal, the two molecules are interconnected by N—H⋯S hydrogen bonds into dimers, which are further consolidated into chains along the b axis by C—H⋯N hydrogen bonds. Weak C–H⋯π and π–π interactions [centroid–centroid distance = 3.5149 (7) Å] are also observed.

3-Acetyl-4-hy­droxy-6,7-dimethyl-2H-chromen-2-one

In the title coumarin derivative, C13H12O4, the 2H-chromene ring system is essentially planar [maximum deviation = 0.047 (1) Å]. An intramolecular hydrogen bond is observed between the hydroxy and the ketonic O atoms. In the crystal, pairs of intermolecular C—H⋯O hydrogen bonds link inversion-related molecules into dimers. Additional intermolecular C—H⋯O hydrogen bonds further interconnect these dimers into two-dimensional arrays incorporating R 2 2(9) ring motifs.

3-[(E)-3-(2,4-Dichloro-phen-yl)prop-2-en-oyl]-4-hy-droxy-2H-chromen-2-one.

In the title compound, C18H10Cl2O4, the chromen-2-one ring system is almost planar [maximum deviation = 0.028 (1) Å] and is inclined at an angle of 16.35 (4)° with respect to the benzene ring. The C=C bond has an E configuration. The molecular conformation is stabilized by an almost symmetric intramolecular O⋯H⋯O hydrogen bond and a C—H⋯O interaction, both of which form S(6) ring motifs. In the crystal structure, molecules are linked into sheets lying parallel to (100) via intermolecular C—H⋯O hydrogen bonds. The crystal packing is further consolidated by π–π stacking interactions [centroid-to-centroid separation = 3.6615 (6) Å].

4-Hy­droxy-3-[(4-hy­droxy-2-oxo-2H-3-chromen­yl)(3-thien­yl)meth­yl]-2H-chromen-2-one

The whole molecule of the title compound, C23H14O6S, is disordered over two sets of sites with refined occupancies of 0.8733 (12):0.1267 (12). The dihedral angle between the mean planes through the chromene ring systems is 56.31 (5) and 55.2 (3)° for the major and minor components, respectively. In both components, a pair of intramolecular O—H⋯O interactions generate rings of S(8) graph-set motif. In the crystal, the molecules are linked by intermolecular C—H⋯O interactions, forming chains along the b axis. The structure is further stabilized by π–π interactions with centroid–centroid distances of 3.594 (2) and 3.608 (5) Å.

3-Hydroxy-2-[(2-hydroxy-4,4-dimethyl-6-oxocyclohex-1-en-1-yl)(thiophen-3-yl)methyl]-5,5-dimethylcyclohex-2-en-1-one.

The asymmetric unit of the title compound, C21H26O4S, consists of two independent molecules. In both molecules, intramolecular O—H⋯O hydrogen bonds stabilize the molecular structure. In the crystal, each molecule and its symmetry-related molecule by twofold rotation form a dimer through a pair of intermolecular C—H⋯O hydrogen bonds. In one of the molecules, the thiophene group is disordered over two sets of sites with occupancies of 0.735 (3) and 0.265 (3).