In the title compound, C10H4ClNO5, the non-H atoms of the 6-chloro-chromone unit are coplanar (r.m.s. deviation = 0.017 Å) with the largest deviation from the mean plane [0.031 (2) Å] being found for the C=O C atom. The nitro group (NO2) is inclined to the chromone unit mean plane by 13.3 (2) °. The formyl group is also twisted with respect to the attached ring [C-C-C-O torsion angles = 10.8 (4...

In the title compound, C(11)H(8)O(3), the benzopyran-4-one or chromone ring system is almost planar, with a maximum deviation of 0.045 (2) Å. The crystal structure is stablized by π-π inter-actions between the benzene and pyran rings of inversion-related mol-ecules stacked along the b axis, with a centroid-centroid distance of 3.5463 (12) Å

In the title compound, C10H5ClO3, a chlorinated 3-formyl-chromone derivative, all atoms are essentially coplanar (r.m.s. deviation = 0.0592 Å for all non-H atoms), with the largest deviation from the least-squares plane [0.1792 (19) Å] being for the chromone-ring carbonyl O atom. In the crystal, mol-ecules are linked through C-H⋯O hydrogen bonds to form tetrads, which are assembled by stacking ...

In the title compound, C10H5IO3, an iodinated 3-formyl-chromone derivative, the non-H atoms are essentially coplanar (r.m.s. deviation = 0.0259 Å), with the largest deviation from the least-squares plane [0.056 (5) Å] being found for the formyl O atom. In the crystal, mol-ecules are linked through I⋯O halogen bonds [I⋯O = 3.245 (4) Å, C-I⋯O = 165.95 (13) and C=O⋯I = 169.7 (4)°] along [101]. The...

In the title compound, C11H7ClO3, a chlorinated and methyl-ated 3-formyl-chromone derivative, the non-H atoms are essentially coplanar (r.m.s. deviation = 0.0670 Å), with the largest deviation from the least-squares plane [0.2349 (17) Å] being for the pyran carbonyl O atom. In the crystal, mol-ecules are linked through π-π stacking inter-actions along the a axis [centroid-centroid distance betw...

In the title compound, C10H6O4, also known as 3-carb-oxy-chromone, the non-H atoms of the chromone ring are essentially coplanar (r.m.s. deviation = 0.0057 Å), with the maximum deviation from their least-squares plane [0.011 (2) Å] being for a pyran C atom. The dihedral angle between the fused ring and plane of the carb-oxy group is 3.06 (2)°. An intra-molecular hydrogen bond is formed between ...

The crystal structures of the 3-substituted tertiary chromone carboxamide derivative, C17H13NO3, N-methyl-4-oxo-N-phenyl-4H-chromene-3-carboxamide (1), and the chromone carbonyl pyrrolidine derivatives, C14H13NO3, 3-(pyrrolidine-1-carbon-yl)-4H-chromen-4-one (3) and 2-(pyrrolidine-1-carbon-yl)-4H-chromen-4-one (4) have been determined. Their structural features are discussed and compared with s...

In the title compound, C10H4Br2O3, the atoms of the 6,8-di-bromo-chromone unit are essentially coplanar [largest deviation from the mean planes = 0.1109 (3) Å] and the formyl group is twisted slightly with respect to the attached ring [C-C-C-O torsion angles = 11.5 (4) and -168.9 (3)°]. In the crystal, mol-ecules are linked to each other through halogen bonds [Br⋯O = 3.118 (2) Å, C-Br⋯O = 162.3...