7-Diethylamino-2-oxo-2H-chromene-3-carbaldehyde

In the title compound, C14H15NO3, all non-H atoms except for those of the methyl and the disordered ethyl groupare approximately co-planar, the largest deviation from the mean plane being 0.0223 (13) Å at the N atom. In the crystal, the packing of molecules through weak intermolecular C—H⋯O hydrogen-bonding interactions leads to the formation of layers parallel to bc plane. Within these layers, there exist slipped π–π stacking interactions between symmetry-related fused rings [centroid–centroid distances = 3.527 (3) and 3.554 (3), slippage = 0.988 and 1.011 Å, respectively]. One ethyl group is disordered over two sets of sites with site-occupation factors of 0.54 and 0.46.

In the title compound, C 14 H 15 NO 3 , all non-H atoms except for those of the methyl and the disordered ethyl groupare approximately co-planar, the largest deviation from the mean plane being 0.0223 (13) Å at the N atom. In the crystal, the packing of molecules through weak intermolecular C-HÁ Á ÁO hydrogen-bonding interactions leads to the formation of layers parallel to bc plane. Within these layers, there exist slippedstacking interactions between symmetry-related fused rings [centroid-centroid distances = 3.527 (3) and 3.554 (3), slippage = 0.988 and 1.011 Å , respectively]. One ethyl group is disordered over two sets of sites with siteoccupation factors of 0.54 and 0.46.
The molecule of title compound formed by two fused rings is mainly planar with the exception of the methyl and disordered ethyl group (Fig. 1). The weak intermolcular C-H···O hydrogen bonds (Table 1) link the molecules into layers parallel to the (100) plane. Futhermore, slipped π-π stacking occurs between symetry related fused rings within the layers ( Table 2)

Experimental
The title compound was prepared according to the literature (Wu et al., 2007). Single crystals suitable for X-ray diffraction were prepared by recrystallization from mixture of dichloromethane and petroleum (60-90 °C).

Refinement
Carbon-bound H-atoms were placed in calculated positions (C-H 0.93 to 0.97 Å) and were included in the refinement in the riding model with U iso (H) = 1.2 or 1.5 U eq (C methyl ).
One of the ethyl group is disordered over two positions with a site occupancy in the ratio 0.54/0.46. The refinement of the disordered moieties was carried out using the PART instruction and restraining them to have identical geometry with the SAME instruction available in SHELXL-97 (Sheldrick, 2008) Figures Fig. 1. The crystal structure of the title compound, with the atom numbering scheme. Displacement ellipsoids of non-H atoms are drawn at the 30% probalility level. H atoms are shown as small spheres of arbitrary radii. Only the major component of the disordered ethyl is represented for clarity.