(2E)-2-(5-Bromo-2-hydroxy-3-methoxybenzylidene)-N-cyclohexylhydrazinecarbothioamide

The title compound, C15H20BrN3O2S, crystallizes in the thioamide form and adopts an E,E conformation with respect to the azomethine and hydrazinic bonds, respectively. The molecules are paired through N—H⋯O and O—H⋯S hydrogen bonds, leading to the formation of centrosymmetric dimers in the crystal. These dimers are stacked along the a axis and are interconnected through N—H⋯S hydrogen bonds to generate polymeric chains. The structure also features C—H⋯π interactions. An intramolecular O—H⋯O bond is also present.

The title compound, C 15 H 20 BrN 3 O 2 S, crystallizes in the thioamide form and adopts an E,E conformation with respect to the azomethine and hydrazinic bonds, respectively. The molecules are paired through N-HÁ Á ÁO and O-HÁ Á ÁS hydrogen bonds, leading to the formation of centrosymmetric dimers in the crystal. These dimers are stacked along the a axis and are interconnected through N-HÁ Á ÁS hydrogen bonds to generate polymeric chains. The structure also features C-HÁ Á Á interactions. An intramolecular O-HÁ Á ÁO bond is also present.
Cg1 is the centroid of the C1-C6 ring.
The mean plane deviation calculations show that the molecule as a whole is non-planar. But the central hydrazinecarbothioamide group (C7/N1/N2/C8/S1/N3/C9) is almost planar with a maximum deviation from the mean plane of -0.054 (2) Å for atom N1. This is similar to that observed in salicylaldehyde-N(4)-phenyl thiosemicarbazone (Seena et al., 2008).

Experimental
The preparation of this compound involves a two step process (Klayman et al., 1979). In the first step, cyclohexyl isothiocyanate (15 mmol, 2 ml) in 15 ml methanol and hydrazine hydrate (90 mmol, 4.3 ml) in 15 ml methanol were mixed and the resulting solution was stirred for an hour. The white product, N(4)-cyclohexylthiosemicarbazide formed was filtered, washed with methanol and dried in vacuo. In the second step, a methanolic (20 ml) solution of 4-cyclohexylthiosemicarbazide (1 mmol, 0.1732 g) was added to a solution of 5-bromo-3-methoxysalicylaldehyde (1 mmol, 0.2310 g) in 15 ml methanol and the reaction mixture was refluxed for 2 h in acid medium. The product formed was filtered, washed with methanol and dried in vacuo. Suitable crystals were grown by slow evaporation of its solution in 1:1 mixture of DMF and methanol over 2 days.

Refinement
All H atoms on C were placed in calculated positions, guided by difference maps, with C-H bond distances 0.93-0.97 Å. H atoms were assigned as U iso =1.2Ueq (1.5 for Me). N2-H2, N3-H3′ and O2-H2′ H atoms were located from difference maps and restrained using DFIX instructions.

Figure 1
The title compound, showing 50% probability displacement ellipsoids and the atom-numbering scheme.

Figure 2
A view of the unit cell along a axis. where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max = 0.001 Δρ max = 0.27 e Å −3 Δρ min = −0.41 e Å −3 Extinction correction: SHELXL97 (Sheldrick, 2008), Fc * =kFc[1+0.001xFc 2 λ 3 /sin(2θ)] -1/4 Extinction coefficient: 0.0142 (18) Special details 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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )
x y z U iso */U eq  (4)