(E)-1-[1-(6-Bromo-2-oxo-2H-chromen-3-yl)ethylidene]thiosemicarbazide

The title compound, C12H10BrN3O2S, exists in an E configuration with respect to the C=N bond. The approximately planar 2H-chromene ring system [maximum deviation = 0.059 (1) Å] is inclined at a dihedral angle of 17.50 (5)° with respect to the mean plane through the thiosemicarbazide unit and an intramolecular N—H⋯N hydrogen bond generates an S(5) ring. In the crystal structure, adjacent molecules are linked by N—H⋯S hydrogen bonds, forming [010] chains built up from R 2 2(8) loops, such that each S atom accepts two such bonds. These chains are further interconnected into sheets parallel to the ab plane via short Br⋯O interactions [3.0732 (13) Å] and a π–π aromatic stacking interaction [3.7870 (8) Å] is also observed.

The objective of this study is to synthesize new derivatives of coumarin-thiosemicarbazide compounds. We present in this paper the crystal structure of this title compound.

Experimental
Coumarin thiosemicarbazone was prepared by cyclocondensation of 5-bromosalicylaldehyde with ethylacetoacetate and the resulting acetyl coumarin intermediate was then treated with thiosemicarbazide to get the title compound as reported in the literature with some modifications (Moamen et al., 2009). The methanol solution of thiosemicarbazide (5.00 mmol) was added to a solution of 6-bromo-(3-acethylcoumarin) (5.00 mmol) in hot methanol (10 ml) while stirring. The resulting solution was refluxed for 1 h and then pH of the solution was adjusted to 4-5 by adding glacial acetic acid. The solution was again refluxed for 4 h. The title compound was recrystallized from ethyl acetate:ethanol (2:1) to give yellow needles of (I).
supplementary materials sup-2 Refinement H atoms bound to N atoms were located from difference Fourier map and allowed to refine freely [range of N-H = 0.73 (3)-0.82 (3) Å]. All other H atoms were placed in their calculated positions, with C-H = 0.93 or 0.96 Å, and refined using a riding model, with U iso = 1.2 or 1.5 U eq (C). A rotating group model was used for the C12 methyl group. Fig. 1. The molecular structure of (I), showing 50 % probability displacement ellipsoids for non-H atoms.

Special details
Experimental. The crystal was placed in the cold stream of an Oxford Cryosystems Cobra open-flow nitrogen cryostat (Cosier & Glazer, 1986) operating at 100.0 (1)K.

sup-4
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.
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 > 2sigma(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