2-Methoxy-9-phenoxyacridine

The molecules in the crystal structure of the title compound, C20H15NO2, form inversion dimers connected through the C—H⋯N and π–π interactions. These dimers are further linked by C—H⋯π interactions. The methoxy group is nearly coplanar with the acridine ring system [dihedral angle = 4.5 (1)°], whereas the phenoxy fragment is nearly perpendicular to it [dihedral angle = 85.0 (1)°]. The mean planes of the acridine ring systems are either parallel or inclined at angles of 14.3 (1), 65.4 (1) and 67.3 (1)° in the crystal.

The molecules in the crystal structure of the title compound, C 20 H 15 NO 2 , form inversion dimers connected through the C-HÁ Á ÁN andinteractions. These dimers are further linked by C-HÁ Á Á interactions. The methoxy group is nearly coplanar with the acridine ring system [dihedral angle = 4.5 (1) ], whereas the phenoxy fragment is nearly perpendicular to it [dihedral angle = 85.0 (1) ]. The mean planes of the acridine ring systems are either parallel or inclined at angles of 14.3 (1), 65.4 (1) and 67.3 (1) in the crystal.
In the crystal structure, the inversely oriented molecules form dimers through π-π interactions involving acridine skeletons (  Fig. 2). These dimers are linked in the crystal lattice by C(aliphatic, aromatic)-H···π interactions (Table 1, Fig. 2). The C-H···N interactions are of the hydrogen bond type (Steiner, 1999). The C-H···π interactions (Takahashi et al., 2001), like the π-π interactions (Hunter et al., 2001) should be of an attractive nature. The crystal structure is stabilized by a network of these short-range specific interactions and by non-specific dispersive interactions between adjacent molecules.
In the title compound ( Fig. 1), the bond lengths and angles characterizing the geometry of the acridine moiety are typical of acridine based derivatives (Ebead et al., 2005;Sikorski et al., 2007). With a respective average deviation from planarity of 0.0147 (2) Å and 0.0072 (2) Å, the acridine and benzene ring systems are oriented at 85.0 (1)°, i.e. they are nearly perpendicular to each other. On the other hand, the methoxy group is almost co-planar with the acridine skeleton (the angle between the mean plane of the acridine moiety and the plane delineated by C2, O15 and C16 is 4.5 (1)°). C9, N10 and O17 are arranged almost linearly (N10···C9-O17 angle = 174.9 (1)°). The mean planes of the adjacent acridine moieties are either parallel (they remain at an angle of 0.0 (1)° -in dimers) or inclined at angles of 14.3 (1)°, 65.4 (1)° and 67.3 (1)° in the lattice. The molecular structure of the compound investigated is similar to that of 9-phenoxyacridine (Ebead et al., 2005).
Experimental 2-Methoxy-9-chloroacridine was prepared by heating 2-[(2-methoxyphenyl)amino]benzoic acid, obtained as described elsewhere (Acheson, 1973), with a sevenfold molar excess of POCl 3 (400 K, 3 h). The excess POCl 3 was subsequently removed under reduced pressure. The residue was dispersed in CHCl 3 , stirred in the presence of a mixture of ice and aqueous ammonia, separated by filtration and dried. The crude product was purified chromatographically (neutral Al 2 O 3 , CHCl 3 /toluene, 1/1 v/v). The obtained 2-methoxy-9-chloroacridine was added to the solution of NaOH in phenol (sevenfold molar excess) in equimolar to NaOH amount, at 373 K under continuous stirring. The reactant mixture was kept at 373 K for 1.5 h, subsequently poured into 2M aq NaOH and stored at room temperature overnight. The precipitate was separated by filtration, supplementary materials sup-2 washed with water and dried (Duprè & Robinson, 1945;Chen et al., 2002). Light-brown crystals of 2-methoxy-9-phenoxyacridine suitable for X-Ray investigations were grown from absolute ethanol solution (m.p. 415-417 K).

Refinement
H atoms were positioned geometrically, with C-H = 0.93 Å (aromatic) or 0.96 Å (methyl), and constrained to ride on their parent atoms with U iso (H) = 1.2U eq (C) (aromatic) or U iso (H) = 1.5U eq (C) (methyl). Fig. 1. The molecular structure of the title compound showing the atom labeling scheme. Displacement ellipsoids are drawn at the 25% probability level and H atoms are shown as small spheres of arbitrary radius. Cg1, Cg2, Cg3 and Cg4 denote the ring centroids.

Special details
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.