2-[(4-Chlorobenzyl)sulfanyl]-4-(2-methylpropyl)-6-(phenylsulfanyl)pyrimidine-5-carbonitrile

In the title compound, C22H20ClN3S2, the S-bound benzene rings are inclined [dihedral angles = 78.13 (10) and 36.70 (9)°] with respect to the pyrimidine ring. The methylpropyl group occupies a position normal to the pyrimidine ring [N—C—C—C torsion angle = 92.3 (2)°]. In the crystal, supramolecular layers are formed in the bc plane, being consolidated by C—H⋯π and π—π interactions, the latter between the pyrimidine and S-bound benzene rings [inter-centroid distance = 3.7683 (12) Å].


Related literature
Cg1 is the centroid of the C17-C22 ring.
The financial support of the Deanship of Scientific Research and the Research Center of the College of Pharmacy, King Saud University, is greatly appreciated. We also thank the Ministry of Higher Education (Malaysia) for funding structural studies through the High-Impact Research scheme (UM.C/HIR/MOHE/SC/12).

T. Tiekink Comment
The chemotherapeutic efficacy of pyrimidine derivatives is related to their ability to inhibit vital enzymes responsible for DNA biosynthesis. Thus, several non-nucleoside pyrimidine derivatives exhibit anti-cancer (Al-Safarjalani et al., 2005), anti-viral (Brunelle et al., 2007Ding et al., 2006) and anti-bacterial activities (Al-Abdullah et al., 2011). In continuation of our interest in the chemical, pharmacological and structural properties of pyrimidine derivatives (El-Emam et al., 2011), we synthesized the title compound as a potential chemotherapeutic agent.

Experimental
To a solution of 2-(4-chlorobenzylsulfanyl)-6-chloro-4-(2-methylpropyl)pyrimidine-5-carbonitrile (705 mg, 2 mmol) in dry pyridine (3 ml), thiophenol (220 mg, 2 mmol) was added and the mixture was heated under reflux for 6 h. On cooling, the solvent was distilled off in vacuo and water (5 ml) was added to the residue. The separated precipitate was filtered, washed with cold water, dried and crystallized from ethanol to yield 724 mg (85%) of the title compound as colourless crystals. M.pt: 394-396 K. Crystals for the X-ray analysis were obtained by slow evaporation of a solution of the title compound in CHCl 3 :EtOH (1:1, 5 ml) held at room temperature.

Refinement
Carbon-bound H-atoms were placed in calculated positions [C-H = 0.93 to 0.98 Å, U iso (H) = 1.2-1.5U eq (C)] and were included in the refinement in the riding model approximation.   A view in projection down the b axis of the unit-cell contents for the title compound. The C-H···π and π-π interactions are shown as brown and purple dashed lines, respectively.

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