1-(4-Chlorobutanoyl)-3-(3-chlorophenyl)thiourea

The two independent molecules in the asymmetric unit of the title compound, C11H12Cl2N2OS, exhibit different conformations, with the benzene ring and the N2CS thiourea group forming dihedral angles of 87.40 (18) and 69.42 (15)°. An intramolecular N—H⋯O hydrogen bond is present in each molecule. Two further N—H⋯O hydrogen bonds link the independent molecules into a dimer. In the crystal, the dimers are linked by N—H⋯S and C—H⋯S hydrogen bonds, forming chains parallel to the c axis.

The two independent molecules in the asymmetric unit of the title compound, C 11 H 12 Cl 2 N 2 OS, exhibit different conformations, with the benzene ring and the N 2 CS thiourea group forming dihedral angles of 87.40 (18) and 69.42 (15) . An intramolecular N-HÁ Á ÁO hydrogen bond is present in each molecule. Two further N-HÁ Á ÁO hydrogen bonds link the independent molecules into a dimer. In the crystal, the dimers are linked by N-HÁ Á ÁS and C-HÁ Á ÁS hydrogen bonds, forming chains parallel to the c axis.

Comment
Halogeno-carbonoylthiourea derivatives are useful starting materials for the synthesis of other derivatives through the reactivity of the C-halogen bonds. It is also known that the compounds are an important class of organic compounds due to their potential application as ligands and to their biological activities (Abbas et al., 2013).

Experimental
An acetone solution (30 mL) of 3-chloroaniline (0.01 mol, 1.27 g m) was added dropwise into a two-necked roundbottomed flask containing an equimolar amount of 4-chlorobutanoylisothiocyanate (0.01 mol, 1.636 g m). The mixture was refluxed for about 4 h, filtered into a beaker and left to evaporate at room temperature. The filtrate gave colourless crystals after 7 days on slow evaporation of the solvent (yield 78%).

Refinement
H atoms were positioned geometrically with C-H = 0.93-0.97 Å and constrained to ride on their parent atoms with U iso (H) = 1.2U eq (C). The H atoms on the nitrogen atoms were located in difference Fourier map and refined isotropically with the N-H distances constrained to be 0.88 (1) Å. The highest peak and deepest hole are located at 0.73 Å from atom H10 and 0.74 Å from atom Cl2, respectively. One outlier (2 0 0) was omitted from the last cycles of refinement.   The crystal packing of the title compound viewed down the b axis. The dashes lines indicate hydrogen bonds.

1-(4-chlorobutanoyl)-3-(3-chlorophenyl)thiourea
Crystal data C 11 H 12 Cl 2 N 2 OS M r = 291.19 Monoclinic, P2 1 /c Hall symbol: -P 2ybc a = 14.7762 (8)  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.