3-Cyclohexyl-2-thioxo-1,3-thiazolidin-4-one

In the title compound, C9H13NOS2, the complete molecule is generated by crystallographic mirror symmetry, with all the non-H atoms of the rhodanine (2-thioxo-1,3-thiazolidin-4-one) system and two C atoms of the cyclohexyl ring lying on the reflecting plane. The conformation is stabilized by intramolecular C—H⋯O and C—H⋯S interactions. In the crystal, weak π–π interactions at a distance of 3.8140 (5) Å between the centroids of the heterocyclic rings occur.

In the title compound, C 9 H 13 NOS 2 , the complete molecule is generated by crystallographic mirror symmetry, with all the non-H atoms of the rhodanine (2-thioxo-1,3-thiazolidin-4one) system and two C atoms of the cyclohexyl ring lying on the reflecting plane. The conformation is stabilized by intramolecular C-HÁ Á ÁO and C-HÁ Á ÁS interactions. In the crystal, weakinteractions at a distance of 3.8140 (5) Å between the centroids of the heterocyclic rings occur.

Experimental
DS is grateful to Government College University, Lahore, for providing funds under the GCU funded Research Projects Programme.
There exist π-π interactions at a distance of 3.8140 (5) Å between the centroids of the heterocyclic rings.

Experimental
The title compound was prepared by a three step reaction procedure. In the first step cyclohexylamine (9.9 g, 0.1 mol) and triethylamine (50.5 g, 0.5 mol) were stirred in ethanol (20 ml) followed by dropwise addition of CS 2 (15.2 g, 0.2 mol) while keeping the flask in an ice bath. The precipitate obtained were filtered off and washed with diethyl ether.
In second step, a solution of sodium chloroacetate (11.6 g, 0.1 mol) and chloroacetic acid (18.9 g, 0.2 mol) was prepared in 50 ml distilled water. To this solution the precipitates obtained in first step were added gradually and stirred at 273 K.
This mixture was stirred untill it turned clear yellow.
In third step the yellow mixture was mixed in 140 ml hot (363-368 K) hydrochloric acid (6 N) and stirred for five minutes to obtain colorless crystalline precipitates. These precipitates were recrystalized in chloroform to get colourless prisms of (I).

Refinement
The coordinates of H2 were refined. The other H-atoms were positioned geometrically (C-H = 0.97-0.98 Å) and refined as riding with U iso (H) = 1.2U eq (C). Fig. 1. View of (I) with displacement ellipsoids drawn at the 50% probability level. The dotted lines represen the intramolecular H-bonds.

Special details
Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All su's are estimated from the variances of the (full) variance-covariance matrix. The cell e.s.d.'s are taken into account in the estimation of distances, angles and torsion angles 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.