5-[(4-Ethoxyanilino)methyl]-N-(2-fluorophenyl)-6-methyl-2-phenylpyrimidin-4-amine

The asymmetric unit of the title compound, C26H25FN4O, consists of two symmetry-independent molecules, denoted A and B. The conformation of each molecule is mainly determined by an intramolecular N—H⋯N hydrogen bond, which closes a six-membered ring. The dihedral angles between the pyrimidine ring and the phenyl, fluorophenyl and ethoxyphenyl rings are 15.4 (2), 28.4 (2) and 77.5 (2)°, respectively, in molecule A, and 15.9 (2), 2.7 (2) and 61.8 (2)° in molecule B. Intermolecular N—H⋯N hydrogen bonds and π–π stacking interactions between pyrimidine rings [centroid–centroid distance = 3.692 (4) Å] connect molecules A and B into dimers and C—H⋯O hydrogen bonds link the dimers into zigzag chains along [011]. The (4-ethoxyanilino)methyl group of the B molecule is disordered over two sets of sites, the occupancy factor for the major component being 0.900 (2).

The asymmetric unit of the title compound, C 26 H 25 FN 4 O, consists of two symmetry-independent molecules, denoted A and B. The conformation of each molecule is mainly determined by an intramolecular N-HÁ Á ÁN hydrogen bond, which closes a six-membered ring. The dihedral angles between the pyrimidine ring and the phenyl, fluorophenyl and ethoxyphenyl rings are 15.4 (2), 28.4 (2) and 77.5 (2) , respectively, in molecule A, and 15.9 (2), 2.7 (2) and 61.8 (2) in molecule B. Intermolecular N-HÁ Á ÁN hydrogen bonds and stacking interactions between pyrimidine rings [centroidcentroid distance = 3.692 (4) Å ] connect molecules A and B into dimers and C-HÁ Á ÁO hydrogen bonds link the dimers into zigzag chains along [011]. The (4-ethoxyanilino)methyl group of the B molecule is disordered over two sets of sites, the occupancy factor for the major component being 0.900 (2).
The asymmetric unit of title crystal consists of two independent molecules, hereafter referred to as A and B (C in case of disordered part attached to C5B), respectively (Fig. 1). The conformation of both molecules is dominated by the dihedral angles between the pyrimidine ring plane and those of the phenyl ring attached to the atom C2 and two other aryl rings of the (2-fluorophenyl)amino or (4-ethoxyphenyl)aminomethyl groups, attached to the atoms C4 or C5 of the pyrimidine ring, respectively (Table 1). These dihedral angles are 15.4 (2), 28.4 (2) and 77.5 (2)° in molecule A and 15.9 (2), 2.7 (2) and 61.8 (2)° in molecule B, respectively.
The molecules of title compound are linked by a combination of N-H···N and C-H···O hydrogen bonds and also the aromatic π-π stacking interactions ( Table 2). The C-H···π(arene) hydrogen-bond interactions are absent. The N5 amine atom of molecule A acts as hydrogen-bond donor to the pyrimidine atom N1 of molecule B at (-x + 1, -y + 1, -z + 1).
Simultaneously, the amine atom N5 of molecule B acts as hydrogen-bond donor to the pyrimidine atom N3 of molecule A at (-x + 1, -y + 1, -z + 1). This results in the formation of a dimer via a cyclic R 2 2 (14) ring motif. Between pyrimidine rings of molecules forming the dimer there is also an aromatic π-π stacking interaction (Fig. 2). The angle between the planes of these rings is 2.84 (8)°. The distance between the ring centroids of the molecules at (x, y, z) and (-x + 1, -y + 1,z + 1) is 3.692 (4) Å with an interplanar spacing of 3.647 (4) Å and a centroid offset of 0.57 Å. The intermolecular N-H···N interaction was also observed in the polymorphic form of N-(4-chlorophenyl)-5- [(4-chlorophenyl)aminomethyl]-6methyl-2-phenylpyrimidin-4-amine (denoted as Ia), but the propagation of such linkage generated a chain (Cieplik et al., 2006). In the structure of title compound, intermolecular C-H···O hydrogen bonds between the aryl atoms C46A and C23B and the ethoxy atom O5B and O5A at (x, y + 1, z + 1), respectively (Table 2, Fig. 2) links the molecules into extended zigzag chains which run parallel to the [011] direction and can be described by a C(15) motif.

Experimental
The title compound was obtained by adopting the procedure described previously by Cieplik et al. (2003). 4 g (0.0122 mmol) of 5-(chloromethyl)-N-(2-fluorophenyl)-6-methyl-2-phenylpyrimidin-4-amine was dissolved in 50 ml of tetrahydrofuran, and 4.4 g of 4-ethoxyaniline. The reaction mixture was refluxed for 4 h with vigorous stirring, then was supplementary materials sup-2 . E68, o1729-o1730 cooled and poured into 300 ml of water. The aqueous solution was extracted three times with chloroform (50 ml). The combined chloroform phases were dried over MgSO 4 , filtered and concentrated under vacuum. The oily residue was purified by column chromatography on silica gel (200-300 mesh) using CHCl 3 as the eluent and by crystallization from methanol to give single crystals (yield: 4.1 g, 78.5%, m.p. 397-398 K).

Refinement
The N-bonded H atoms were found from difference Fourier maps and refined with U iso (H) = 1.2 U eq (N). The remaining H atoms were treated as riding on their carrier atoms, with C-H distances in the range 0.95-0.99 Å, and refined with U iso (H) = 1.2 U eq (C), except methyl groups where U iso (H) = 1.5 U eq (C). The (4-ethoxyphenyl)aminomethyl group bonded to the pyrimidine C5B atom of the molecule B was found to be disordered over two sites (denoted as B and C). The occupancy factor of the major component (C51B-C57B and N5B) refined at 0.900 (2). The atoms C51C-C57C and N5C were refined with a common isotropic displacement parameter using EADP instruction of SHELXL97 (Sheldrick, 2008).  The two symmetry independent molecules of the title compound. Two independent molecules are denoted as A and B (or C in the case of disordered part attached to C5B), respectively. In the part C only two atoms are labelled. Displacement