3-Acetyl-1-(2,3-dichlorophenyl)thiourea

In the crystal structure of the title compound, C9H8Cl2N2OS, there are two molecules in the asymmetric unit which are connected by a pair of N—H⋯S hydrogen bonds. An intramolecular N—H⋯O hydrogen bond stabilizes the molecular conformation of each molecule.

In the crystal structure of the title compound, C 9 H 8 Cl 2 N 2 OS, there are two molecules in the asymmetric unit which are connected by a pair of N-HÁ Á ÁS hydrogen bonds. An intramolecular N-HÁ Á ÁO hydrogen bond stabilizes the molecular conformation of each molecule.
The asymmetric unit of the structure contains two molecules. The conformation of the two N-H bonds are anti to each other. Furthermore, the conformations of the amide C═S and the C═O are also anti to each other and both the bonds are anti to the adjacent N-H bonds, similar to the anti conformation observed in 3-acetyl-1-(2,3-dimethylphenyl)thiourea (I) (Kumar et al., 2012). The N-H bond adjacent to the 2,3-dichlorophenyl ring is syn to the ortho-and meta-Cl atoms in one of the molecules and anti in the other molecule, compared to the anti conformation observed with respect to the ortho-and meta-methyl groups in the 2,3-dimethylphenyl ring of (I).
The side chains are oriented themselves with respect to the 2,3-dichlorophenyl rings with the torsion angles, C2-C1- Experimental 3-Acetyl-1-(2,3-dichlorophenyl)thiourea was synthesized by adding a solution of acetyl chloride (0.10 mol) in acetone (30 ml) dropwise to a suspension of ammonium thiocyanate (0.10 mol) in acetone (30 ml). The reaction mixture was refluxed for 30 min. After cooling to room temperature, a solution of 2,3-dichloroaniline (0.10 mol) in acetone (10 ml) was added and refluxed for 3 h. The reaction mixture was poured into acidified cold water. The precipitated title compound was recrystallized to constant melting point from acetonitrile. The purity of the compound was checked and characterized by its infrared spectrum.
Prism like light yellow single crystals used in X-ray diffraction studies were grown in acetonitrile solution by slow evaporation of the solvent at room temperature.

Refinement
The coordinates of the amino H atoms were refined with the N-H distances restrained to 0.86 (2)  Å. All H atoms were refined with their isotropic displacement parameter set to 1.2 times of the U eq of the parent atom.   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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )
x y z U iso */U eq