1-Acetyl-5-(4-fluorophenyl)-2-sulfanylideneimidazolidin-4-one

In the title compound, C11H9FN2O2S, the 2-sulfanylideneimidazolidin-4-one moiety is essentially planar, with a maximum deviation of 0.0183 (14) Å. The mean plane of this moiety is approximately coplanar with the attached acetyl group and perpendicular to the benzene ring, making dihedral angles of 9.70 (14) and 86.70 (6)°, respectively. In the crystal, molecules are linked by N—H⋯O hydrogen bonds between the amide NH and acetyl C=O groups, forming a C(6) chain along the a-axis direction.

In the title compound, C 11 H 9 FN 2 O 2 S, the 2-sulfanylideneimidazolidin-4-one moiety is essentially planar, with a maximum deviation of 0.0183 (14) Å . The mean plane of this moiety is approximately coplanar with the attached acetyl group and perpendicular to the benzene ring, making dihedral angles of 9.70 (14) and 86.70 (6) , respectively. In the crystal, molecules are linked by N-HÁ Á ÁO hydrogen bonds between the amide NH and acetyl C O groups, forming a C(6) chain along the aaxis direction.
In the crystal structure (Fig. 2), the molecules are linked by an N-H···O hydrogen bond between the amide NH and acetyl C═O groups, forming a infinite one-dimensional chain along the a axis, with a C(6) graph-set motif (Table 1).

Experimental
The title compound was synthesized using a slight modification of a reported method (Schlack & Kumpf, 1926). 4-Fluorophenylglycine (0.507 g, 3.00 mmol) was allowed to react with a mixture of ammonium thiocyanate (0.234 g, 3.07 mmol), acetic anhydride (10 ml), and acetic acid (2 ml) at 100 °C for 1 h. A white precipitate was obtained by adding 25 ml distilled water and subsequent cooling the solution in a refrigerator. The crude product was purified by recrystallization from an ethanol solution (yield: 47%). Single crystals suitable for X-ray diffraction were obtained from the ethanol solution.

Refinement
The N-bound H atom was located in a difference map and refined freely [N2-H2 = 0.84 (2)

Figure 1
The molecular structure of the title compound, with the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level.  A partial packing diagram of the title compound, viewed down the c axis. Hydrogen bonds are shown as dashed cyan lines (see Table 1 for details). An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes. Refinement. Refinement was performed using all reflections. The weighted R-factor (wR) and goodness of fit (S) are based on F 2 . R-factor (gt) are based on F. The threshold expression of F 2 > 2.0 σ(F 2 ) is used only for calculating R-factor (gt).