Crystal structure of (5Z)-5-(5-bromo-2-hydroxybenzylidene)-1,3-thiazolidine-2,4-dione

In the title compound, C10H6BrNO3S, the dihedral angle between the thiazolidine ring (r.m.s. deviation = 0.014 Å) and the benzene ring is 5.78 (14)°. The S atom of the heterocyclic ring is syn to the OH group attached to the benzene ring. In the crystal, inversion dimers linked by pairs of N—H⋯O hydrogen bonds generate R 2 2(8) loops. The dimers are linked into [001] ribbons by pairwise O—H⋯O hydrogen bonds with R 2 2(18) motifs. There are no short contacts involving the Br atom.

In the title compound, C 10 H 6 BrNO 3 S, the dihedral angle between the thiazolidine ring (r.m.s. deviation = 0.014 Å ) and the benzene ring is 5. 78 (14) . The S atom of the heterocyclic ring is syn to the OH group attached to the benzene ring. In the crystal, inversion dimers linked by pairs of N-HÁ Á ÁO hydrogen bonds generate R 2 2 (8) loops. The dimers are linked into [001] ribbons by pairwise O-HÁ Á ÁO hydrogen bonds with R 2 2 (18) motifs. There are no short contacts involving the Br atom.

S1. Comment
Chalcones exhibit a wide spectrum of biological activities including antimicrobial, anticancer, anti-protozoal, antiulcer, and antiinflammatory ones (Nowakowska, 2007;Singh et al., 2011). The tiazolidinone ring system has attracted the attention of many researchers to explore this skeleton to its multiple potential against several activities (Cunico et al., 2008;Verma & Saraf, 2008;Hamama et al., 2008). In this context we report here the synthesis and crystal structure of the title compound.
In the title molecule, the dihedral angle between the 6-and 5-membered rings is 5.8 (1)°. The molecules associate into dimers across centers of symmetry via pairwise N1-H2···O3 hydrogen bonds and these dimers associate with neighboring dimers through pairwise O1-H1···O3 hydrogen bonds across additional centers of symmetry to form ribbons ( Fig. 2 and Table 1). Stacking of these ribbons generates the three-dimensional structure (Fig. 3).

S3. Refinement
Analysis of 1039 reflections having I/σ(I) > 13 and chosen from the full data set with CELL_NOW (Sheldrick, 2015) showed the crystal to belong to the triclinic system and to be twinned by a 180° rotation about c*. The raw data were The title molecule with 50% displacement ellipsoids.

Figure 2
A portion of one layer generated by N-H···O and O-H···O hydrogen bonds (blue and red dotted lines respectively.

Figure 3
Elevation view of the layer structure with hydrogen bonds shown as in Fig. 2. Special details Experimental. The diffraction data were obtained from 3 sets of 400 frames, each of width 0.5° in ω, colllected at φ = 0.00, 90.00 and 180.00° and 2 sets of 800 frames, each of width 0.45° in φ, collected at ω = -30.00 and 210.00°. The scan time was 20 sec/frame. Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes. 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. Analysis of 1039 reflections having I/σ(I) > 13 and chosen from the full data set with CELL_NOW (Sheldrick, 2008a) showed the crystal to belong to the triclinic system and to be twinned by a 180° rotation about c*. The raw data were processed using the multi-component version of SAINT under control of the two-component orientation file generated by CELL_NOW. Hatoms attached to carbon were placed in calculated positions (C-H = 0.95 -0.99 Å) while those attached to nitrogen and to oxygen were placed in locations derived from a difference map and their coordinates adjusted to give N-H = 0.91%A and O-H = 0.84%A. All were included as riding contributions with isotropic displacement parameters 1.2 times those of the attached atoms. In the final stages of the refinement, runs using the full set of twinned data gave poorer results (in particular large residual peaks in the vicinity of Br1) than did the single-component data extracted with TWINABS (Sheldrick, 2015). Consequently the refinement was completed with the single-component data.

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