N-(4-Methoxyphenyl)-6-methyl-2-phenyl-5-{[4-(trifluoromethyl)anilino]methyl}pyrimidin-4-amine

The title compound, C26H23F3N4O, crystallizes with two symmetry-independent molecules in the asymmetric unit, denoted A and B, which differ mainly in the rotation of the methoxyphenyl ring. The –CF3 group of molecule B is disordered by rotation, with the F atoms split over two sets of sites; the occupancy factor for the major component is 0.853 (4). The dihedral angles between the pyrimidine ring and the attached phenyl, methoxyphenyl and trifluoromethylphenyl rings are 8.1 (2), 37.5 (2) and 70.7 (2)°, respectively, in molecule A, and 9.3 (2), 5.3 (2) and 79.7 (2)° in molecule B. An intramolecular N—H⋯N hydrogen bond occurs in each molecule. In the crystal, two crystallographically independent molecules associate into a dimer via a pair of N—H⋯N hydrogen bonds, with a resulting R 2 2(12) ring motif and π–π stacking interactions [centroid–centroid distance = 3.517 (4) Å] between the pyrimidine rings. For the A molecules, there are intermolecular C—H⋯O hydrogen bonds between an aryl C atom of methoxyphenyl ring and a methoxy O atom of an adjacent molecule. A similar interaction is lacking in the B molecules.

The title compound, C 26 H 23 F 3 N 4 O, crystallizes with two symmetry-independent molecules in the asymmetric unit, denoted A and B, which differ mainly in the rotation of the methoxyphenyl ring. The -CF 3 group of molecule B is disordered by rotation, with the F atoms split over two sets of sites; the occupancy factor for the major component is 0.853 (4). The dihedral angles between the pyrimidine ring and the attached phenyl, methoxyphenyl and trifluoromethylphenyl rings are 8.1 (2), 37.5 (2) and 70.7 (2) , respectively, in molecule A, and 9.3 (2), 5.3 (2) and 79.7 (2) in molecule B. An intramolecular N-HÁ Á ÁN hydrogen bond occurs in each molecule. In the crystal, two crystallographically independent molecules associate into a dimer via a pair of N-HÁ Á ÁN hydrogen bonds, with a resulting R 2 2 (12) ring motif andstacking interactions [centroid-centroid distance = 3.517 (4) Å ] between the pyrimidine rings. For the A molecules, there are intermolecular C-HÁ Á ÁO hydrogen bonds between an aryl C atom of methoxyphenyl ring and a methoxy O atom of an adjacent molecule. A similar interaction is lacking in the B molecules.
The title compound, namely N-(4-methoxyphenyl)- 6-methyl-2-phenyl-5-[(4-trifluoromethylanilino)methyl]pyrimidin-4amine, crystallizes with two symmetry-independent molecules in the asymmetric unit, hereafter referred to as A and B ( Fig. 1). The molecules differ in the orientation of the methoxyphenyl group with respect to the pyrimidine ring; the angle between the least-squares planes through the pyrimidine and aryl rings is 37.5 (2)° in molecule A and 5.3 (2)° in molecule B. For both molecules, the phenyl ring attached to the atom C2 is nearly co-planar with the pyrimidine ring [dihedral angle = 8.1 (2) and 9.3 (2)° in molecule A and B, respectively], whereas the trifluoromethylphenyl ring attached to the atom C5 is almost perpendicular to pyrimidine ring plane [dihedral angle = 70.7 (2) and 79.7 (2)° in molecule A and B, respectively].
In the crystal structure, the N5 amide 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 amide 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). The result is the formation of a centrosymmetric hydrogen-bonded dimer with the R 2 2 (12) ring motif. Furthemore, between pyrimidine rings of adjacent molecules within a dimer there is also an aromatic π-π stacking interaction (Fig. 2). The angle between the planes of these rings is 1.24 (9)°. The distance between the ring centroids of molecules at (x, y, z) and (-x + 1, -y + 1, -z + 1) is 3.517 (2) Å with an interplanar spacing of 3.488 (4) Å and a centroid offset of 0.45 Å. For molecules A, there are intermolecular C-H···O hydrogen bonds formed between the aryl atom C43A of the methoxyphenyl ring as a donor and the methoxy atom O4A at (-x + 2, -y + 1, -z + 2) as an acceptor (Fig. 2). A similar interaction is lacking in the B molecule. On the whole, a threedimensional arrangment in the crystal structure consists of neighboring dimers, held together by C-H···O, C-F···π and C-H···π interactions as well as π-π interactions [the shortest centroid-centroid distance is 3.574 (4) Å].

Experimental
The title compound was obtained by adopting the procedure described previously by Cieplik et al. (1995). 4 g of 5-(chloromethyl)-N-(4-methoxyphenyl)-6-methyl-2-phenylpyrimidin-4-amine was dissolved in 30 ml of chloroform, and 3 g of 4-(trifluoromethyl)aniline. The reaction mixture was refluxed for 5 h with vigorous stirring, then was cooled and poured into 200 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: 4.3 g, 78.7%, m.p. 469-471 K).

Refinement
The C-H H atoms were positioned with idealized geometry (methyl H atoms allowed to rotate but not to tip) and were refined with U iso (H) = 1.2 U eq (C) (1.5 for methyl H atoms) using a riding model with C-H distances between 0.95-0.99 Å. The -CF 3 group in molecule B is disordered with the F atoms split over two sets of sites and were refined with the occupancy factors of 0.853 (4) and 0.147 (4). The F atoms of higher occupancy were refined anisotropic, whereas those of lower occupancy were refined isotropic.

N-(4-Methoxyphenyl)-6-methyl-2-phenyl-5-{[4-(trifluoromethyl)anilino]methyl}pyrimidin-4-amine
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.