1-Acetyl-5-methoxy-4-(phenylsulfanyl)imidazolidin-2-one

The title compound, C12H14N2O3S, crystallizes with two independent molecules (A and B) in the asymmetric unit. The five-membered imidazolidin-2-one rings in both molecules are twisted about the C—C bond. In the crystal, the A and B molecules are associated via pairs of N—H⋯O hydrogen bonds, forming A–B dimers. These dimers are linked via C—H⋯S hydrogen bonds, forming double dimers, which are in turn linked via C—H⋯O hydrogen bonds forming two-dimensional networks lying parallel to (001). There are also C—H⋯π interactions present, which consolide the layers and link them, so forming a three-dimensional structure.

The title compound, C 12 H 14 N 2 O 3 S, crystallizes with two independent molecules (A and B) in the asymmetric unit. The five-membered imidazolidin-2-one rings in both molecules are twisted about the C-C bond. In the crystal, the A and B molecules are associated via pairs of N-HÁ Á ÁO hydrogen bonds, forming A-B dimers. These dimers are linked via C-HÁ Á ÁS hydrogen bonds, forming double dimers, which are in turn linked via C-HÁ Á ÁO hydrogen bonds forming two-dimensional networks lying parallel to (001).
There are also C-HÁ Á Á interactions present, which consolide the layers and link them, so forming a three-dimensional structure.  Table 1 Hydrogen-bond geometry (Å , ).

Comment
Imidazolidinones are an interesting class of compounds possessing antitumor activity (Abdel-Aziz et al., 2012;Lee et al., 2000;Kim et al., 2003). As a continuation of our studies on new biologically active compounds we report herein on the synthesis and crystal structure of the title compound.
In the crystal the A and B molecules are linked via pairs of N-H···O hydrogen bonds forming dimer-like arrangements (Table 1 and Fig. 2). The phenyl groups project outwards on both edges of the relatively flat central portion of the dimer.
These dimers are linked via C-H···S hydrogen bonds forming double-dimers. These units are linked via C-H···O hydrogen bonds forming two-dimensional networks lying parallel to the ab plane. There are also C-H···π interactions present consolidating the layers and linking them so forming a three-dimensional structure -see Table 1 for details of the hydrogen bonding and C-H···π interactions.

Experimental
Trifluoroacetic acid (0.3 equiv) was added dropwise to a stirred solution of 1-acetyl-4,5-dimethoxyimidazolidin-2-one (1 equiv) and thiophenol (1 equiv) in dry CH 3 CN (0.01 mol/L) over a period of 15 min at room temperature. After being stirred for 2 h at room temperature, the mixture was quenched by adding aqueous ammonium chloride solution (5 ml), extracted with ethyl acetate, washed with brine and dried over anhydrous sodium sulfate. The product obtained after evaporation of the solvent was purified by column chromatography using mixture of hexane and CHCl 3 as eluent.
Colourless rod-like crystals were obtained by slow evaporation of the eluent solution.

Refinement
All H atoms were placed in idealized positions and allowed to ride on the respective parent atom: N-H = 0.88 & 0.89 Å, C-H = 0.95 -1.00 Å with U iso (H) = 1.5U eq (C-methyl) and = 1.2U eq (N,C) for other H atoms.  A view of the molecular structure of the two independent molecules (A and B) of the title compound, with atom labelling.

Computing details
The displacement ellipsoids are drawn at the 50% probability level.

Figure 2
A view along the a axis of the crystal packing of the title compound. The hydrogen bonds are shown as dashed lines (see Table 1 for details).  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. H-atoms attached to carbon were placed in calculated positions (C-H = 0.95 -0.98 Å) while those attached to nitrogen were placed in locations derived from a difference map. All were included as riding contributions with isotropic displacement parameters 1.2 -1.5 times those of the attached atoms.