3-[1-(2-Hydroxyanilino)ethylidene]-3H-chromen-2,4-dione

The title compound is a new aminocoumarin derivative, C17H13NO4, and was synthesized by the condensation of 2-aminophenol and 3-acetyl-4-hydroxycoumarin. An intramolecular N—H⋯O hydrogen bond generates an S(6) ring motif. In the crystal, the molecules are linked into chains extending in the [010] direction by O—H⋯O hydrogen bonds. There is also a π–π stacking interaction between the bicyclic coumarin fragment and the phenol ring [centroid–centroid distance = 3.7510 (14) Å], and these ring systems form between them a dihedral angle of 53.3 (2)°. Intermolecular hydrogen bond C—H⋯O hydrogen bonding is also observed in the interconnection of the crystal packing.


Related literature
Hydrogen-bond geometry (Å , ). Professor A. Ben Salah is acknowledged for his contribution to the X-ray diffraction data collection at the Laboratory of Materials Science and the Environment, University of Sfax, Tunisia.
In the crystal, the title compounds adopts a conformation where the dihedral angle between the plane of the bicyclic coumarin fragment and the phenol ring is 53.3 (2)°. The structure of our solid compound is stable thanks to the intermolecular hydrogen bonds O4-H12···O2. The crystal structure of C 17 H 13 N 1 O 4 shows a π-π stacking interaction alternating between two inverted molecules. The stacking is observed along the b axis with distance 3.361 (4) Å between the layers of coumarin and phenol rings [centroid-centroid distance 3.7510 (14)  hydrogen atoms between the electron-donors and acceptors are highly conjugated, leading to a π-bridge for the charge transfer from aminophenol ring to coumarin system.

Experimental
The amino coumarin was synthesized by the condensation of an equimolar amount of 2-aminophenol and 3-acetyl-4-hydroxycoumarin in absolute ethanol. After four hours of reflux, the reaction mixture was left crystallizing at room temperature. The compound obtained is presented as transparent crystals of light yellow color with shape and size suitable for the structural study of X-ray single-crystal. Yield:(90%). mp= 446 K.

Refinement
The hydrogen atoms are fixed geometrically and refined as riding with the exception of the H13, which was located from electron density difference map and is refined isotropically. U iso (H) values of the H atoms were set at 1.2U eq or 1.5U eq of the parent atom.   Hydrogen bonds between molecules of the title compound.

Special details
Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes. Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.