Ethyl 2-amino-4-(4-fluorophenyl)-6-methoxy-4H-benzo[h]chromene-3-carboxylate

In the title compound, C23H20FNO4, the fluoro-substituted benzene ring is approximately perpendicular to the mean plane of the 4H-benzo[h]chromene ring system [maximum deviation = 0.264 (1) Å], with a dihedral angle of 83.79 (6)°. The pyran ring adopts a flattened boat conformation. The methoxy group is slightly twisted from the attached benzene ring of the 4H-benzo[h]chromene moiety [C—O—C—C = −2.1 (2)°]. An intramolecular N—H⋯O hydrogen bond generates an S(6) ring motif. In the crystal, molecules are linked by N—H⋯O and N—H⋯F hydrogen bonds into a layer parallel to the bc plane. The crystal packing also features C—H⋯π interactions.


organic compounds
The 4H-chromene nucleus is frequently found in bioactive compounds and plays an important role in biochemical processes (Jeso & Nicolaou, 2009;Alvey et al., 2008Alvey et al., , 2009Symeonidis et al., 2009). In addition, 4H-chromenes and fused 4H-chromenes nuclei are used in treatment of Alzheimer's disease and Schizophrenia disorder (Brühlmann et al., 2001). In view of the above observations and in continuation of our program on the chemistry of 4H-pyran derivatives (Bedair et al., 2001;El-Agrody et al., 2002Abd-El-Aziz et al., 2004;Sabry et al., 2011), we report herein the crystal structure of the title compound.
The asymmetric unit of the title compound is shown in Fig. 1 hydrogen bond generates an S(6) ring motif (Bernstein et al., 1995) in the molecule.

Experimental
A solution of 4-methoxy-1-naphthol (0.01 mol) in EtOH (30 ml) was treated with ethyl α-cyano-p-fluorocinnamate (0.01 mol) and piperidine (0.5 ml). The reaction mixture was heated under reflux for 2 h. The obtained solid product was collected by filtration, dried and crystallized from ethanol to give the title compound. M.p.: 435-436 K.

Refinement
The atoms H1N1 and H2N1 were located in a difference Fourier map and refined freely [N-H = 0.88 (2) and 0.89 (2) Å]. The remaining H atoms were positioned geometrically (C-H = 0.93, 0.96, 0.97 and 0.98 Å) and refined using a riding model with U iso (H) = 1.2 or 1.5U eq (C). A rotating group model was applied to the methyl groups.

Figure 1
The molecular structure of the title compound with atom labels and 30% probability displacement ellipsoids.

Figure 2
A packing view of the title compound along the a axis. The dashed lines represent the hydrogen bonds. For clarity sake, hydrogen atoms not involved in hydrogen bonding have been omitted. 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.