1-Methyl-3,3-bis[(4-methylphenyl)sulfanyl]piperidin-2-one

The piperidone ring in the title compound, C20H23NOS2, has a half-chair distorted to a twisted-boat conformation [Q T = 0.5200 (17) Å]. One of the S-bound benzene rings is almost perpendicular to the least-squares plane through the piperidone ring, whereas the other is not [dihedral angles = 75.28 (5) and 46.41 (5) Å, respectively]. In the crystal, the presence of C—H⋯O and C—H⋯π interactions leads to the formation of supramolecular layers in the ab plane.

The piperidone ring in the title compound, C 20 H 23 NOS 2 , has a half-chair distorted to a twisted-boat conformation [Q T = 0.5200 (17) Å ]. One of the S-bound benzene rings is almost perpendicular to the least-squares plane through the piperidone ring, whereas the other is not [dihedral angles = 75.28 (5) and 46.41 (5) Å , respectively]. In the crystal, the presence of C-HÁ Á ÁO and C-HÁ Á Á interactions leads to the formation of supramolecular layers in the ab plane.
The crystal packing of (I), Table 1, is sustained by C-H···O and C-H···π interactions that lead to the formation of supramolecular layers in the ab plane, Fig. 1. The S1-benzene accepts to C-H···π contacts. Layers stack along the c axis as illustrated in Fig.3.
A white solid was obtained after filtration and evaporation without further purification (Hashmat & McDermott, 2002).
1-Methyl-2-piperidinone (1.9 g, 17 mmol) was added drop-wise to a cooled (195 K) solution of hexamethylphosphoramide (HMPA) (3.1 ml, 17 mmol), diisopropylamine (2.6 ml, 17 mmol) and butyllithium (13.5 ml, 17 mmol) in THF (60 ml). After 20 minutes, 4-methylphenyl disulfide (4.1 g, 17 mmol) dissolved in THF (10 ml) was added drop-wise to the enolate solution (Zoretic & Soja, 1976). After the mixture was stirred for 4 h at 195 K, water (80 ml) was added at room temperature and extraction with chloroform was performed. The organic layer was dried over anhydrous sodium sulfate. After evaporation of solvent, a crude solid was obtained. Purification through flash chromatography with a solution of hexane and ethyl acetate in a 7:3 ratio give the pure product (3.3 g, yield = 56%). Suitable crystals for X-ray analysis were obtained by vapour diffusion of n-hexane into a chloroform solution of (I) held at 283 K; m.p. The H atoms were geometrically placed (C-H = 0.95-0.99 Å) and refined as riding with U iso (H) = 1.2-1.5U eq (C). Fig. 1. The molecular structure of (I) showing atom labelling scheme and displacement ellipsoids at the 50% probability level (arbitrary spheres for the H atoms).

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 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 Rfactors(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.