1-(4-Bromophenyl)-3-(2-thienylcarbonyl)thiourea

The title compound, C12H9BrN2OS2, consists of two planar parts, viz. the thiophene ring including all substituents (r.m.s. deviation 0.007 Å) and the benzene ring including the respective substituents as well as the thione group (r.m.s. deviation 0.05 Å). The interplanar angle is 18.84 (6)°. An intramolecular Cphenyl—N—H⋯OC hydrogen bond is observed. The three-dimensional packing involves three types of interactions, viz. N—H⋯S, C—H⋯S (× 2) and Br⋯S [3.6924 (6) Å].


Comment
The development of new antimicrobial and anticancer therapeutic agents is one of the fundamental goals in medicinal chemistry. Cytotoxicity and genotoxicity of anticancer drugs to normal cells are major problems in cancer therapy and engender the risk of inducing secondary malignancy (Aydemir et al., 2003). A dose of an anticancer drug sufficient to kill tumor cells is often toxic to the normal tissue and leads to many side effects, which, in turn, limit the efficacy of treatment.
In recent years, there has been a concerted search for novel selective antitumor agents that lack many of the unpleasant side effects of conventional agents. Thiourea and its derivatives have found extensive applications in the field of medicine, agriculture and analytical chemistry. They are known to exhibit a wide variety of biological activities such as antiviral, anti-bacterial, antifungal, anticancer, antitubercular, herbicidal and insecticidal effects, and also constitute some epoxy resin curing agents containing amino functional groups (Saeed et al., 2008a,b,c). They have found broad areas of application e.g.
in anion recognition, nonlinear optics and catalysis, and also display good coordination ability (Choi et al., 2008;Jones et al., 2008;Su et al., 2006). As part of our research on thiourea coordination chemistry, we are interested in the study of the influence of non-covalent interactions, especially hydrogen bonds and π-π stacking interactions, on the coordination modes of benzothiazoles bearing the 4-nitrobenzoylthiourea group with transition metal ions. Such coordination compounds of thiourea have been studied for various biological systems in terms of their antibacterial, antifungal and anticancer activities (Yunus et al., 2008).The importance of such work lies in the possibility that the next generation of thiourea derivatives might be more efficacious as antimicrobial and anticancer agents. However, a thorough investigation of their structure, activity and stability under biological conditions is required. These detailed investigations could be helpful in designing more potent antimicrobial and anticancer agents for therapeutic use. The condensation of acyl/aroyl thiocyanates with primary amines affords 1,3-disubstituted thioureas in excellent yields in a single step. In the present paper, the crystal structure of the title compound is reported.

Experimental
A mixture of ammonium thiocyanate (26 mmol) and 2-thiophene carbonyl chloride (26 mmol) in anhydrous acetone (60 ml) was stirred for 45 min. 2-Bromoaniline (26 mmol) was added and the reaction mixture was refluxed for 2 h. After cooling, the reaction mixture was poured into acidified cold water. The resulting dark yellow solid was filtered and washed with supplementary materials sup-2 cold acetone. The title compound (I) was obtained as colourless needles and laths of several mm length by recrystallization of the solid from ethyl acetate. These tended to split lengthwise when cut, but eventually a fragment suitable for X-ray structure analysis was found.

Figures
Least-squares planes (x,y,z in crystal coordinates) and deviations from them (* indicates atom used to define plane) 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.