Crystal structures of N-[(4-phenylthiazol-2-yl)carbamothioyl]benzamide and N-{[4-(4-bromophenyl)thiazol-2-yl]carbamothioyl}benzamide from synchrotron X-ray diffraction

The crystal structures of two new thiourea derivatives – potential active pharmaceutical ingredients (APIs) – were studied by synchrotron X-ray diffraction.

In this paper we report a synthetic approach for the preparation of the new thiourea derivatives (I) and (II) containing thiazole fragments, and their structural characterization by synchrotron single-crystal X-ray diffraction.
The planarity of the fragments found in (I) and (II) is determined by the present of bond conjugation within each of them as well as the intramolecular N1-H1Á Á ÁO1 hydrogen bond (Tables 1 and 2, Figs. 1 and 2). The different molecular conformations observed for (I) and (II) may apparently be explained by the various systems of intermolecular interactions present in the crystals (see the Supramolecular features section below).

Supramolecular features
Although the similarity of the molecular geometries and types of intramolecular hydrogen bonds might lead to similar packing motifs, this is not found in the case of (I) and (II). The intermolecular interactions, namely, N-HÁ Á ÁX (X = S, Br) and C-HÁ Á ÁO hydrogen bonding and the secondary SÁ Á ÁS and SÁ Á ÁBr interactions, combine in a different way, give rise to distinct packing motifs.
The situation in the case of (II) is quite different. The molecules of (II) form a three-dimensional framework The molecular structure of (I). Displacement ellipsoids are shown at the 50% probability level. The dashed line indicates the intramolecular hydrogen bond. H atoms are presented as small spheres of arbitrary radius.

Synthesis and crystallization
Benzoyl chloride (0.60 ml, 0.73 g, 5.19 mmol) was added over 5 min to a freshly prepared solution of NH 4 SCN (0.39 g, 5.19 mmol) in acetone (40 ml), and the mixture was heated under reflux for 15 min. After heating, the appropriate 4-arylthiazol-2-amine (4.33 mmol) in acetone (10 ml) was added. The mixture was heated again under reflux for 2 h (Fig. 5). Then excess cracked ice was added with vigorous stirring. The resulting solid was collected and liberally washed with water. These compounds were isolated as pale-yellow crystalline solids in 41% and 45% yield for the 4-phenyl (I) and 4-(4-bromophenyl) (II) derivatives, respectively. Single crystals of the products were obtained by slow crystallization from N,N-dimethylformamide solution.
Spectroscopic and physical data for (

Refinement
Crystal data, data collection and structure refinement details are summarized in Table 3. X-ray diffraction studies were carried out on the 'Belok' beamline ( = 0.96990 Å ) of the National Research Center 'Kurchatov Institute' (Moscow, Russian Federation) using a MAR CCD detector. For each compound, a total of 360 images were collected using an oscillation range of 1.0 (' scan mode) and corrected for absorption using the SCALA program (Evans, 2006). The data were indexed, integrated and scaled using the utility iMOSFLM in the program CCP4 (Battye et al., 2011). The hydrogen atoms of the amino groups were localized in the difference-Fourier map and included in the refinement with fixed positional (riding model) and isotropic displacement parameters [U iso (H) = 1.2U eq (N)]. The other hydrogen atoms were placed in calculated positions with C-H = 0.95 Å and refined using in a riding model with fixed isotropic displacement parameters [U iso (H) = 1.2U eq (C)]. For both compounds, data collection: Automar (MarXperts, 2015); cell refinement: iMOSFLM (Battye et al., 2011); data reduction: iMOSFLM (Battye et al., 2011); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

(II) N-{[4-(4-Bromophenyl)thiazol-2-yl]carbamothioyl}benzamide
Crystal data Special details Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.