Methyl (E)-3-(2-bromo-4,5-dimethoxybenzylidene)dithiocarbazate

The title compound, C11H13BrN2O2S2, was obtained from the condensation reaction of methyl dithiocarbazate and 2-bromo-4,5-dimethoxybenzaldehyde. In the molecule, the benzene ring and dithiocarbazate fragment are located on opposite sides of the C=N bond, showing an E conformation. The dithiocarbazate fragment is approximately planar (r.m.s deviation = 0.0281 Å) and the mean plane is oriented at a dihedral angle of 11.38 (15)° with respect to the benzene ring. In the crystal, pairs of N—H⋯S hydrogen bonds link the molecules into centrosymmetric dimers.

The title compound, C 11 H 13 BrN 2 O 2 S 2 , was obtained from the condensation reaction of methyl dithiocarbazate and 2bromo-4,5-dimethoxybenzaldehyde. In the molecule, the benzene ring and dithiocarbazate fragment are located on opposite sides of the C N bond, showing an E conformation. The dithiocarbazate fragment is approximately planar (r.m.s deviation = 0.0281 Å ) and the mean plane is oriented at a dihedral angle of 11.38 (15) with respect to the benzene ring. In the crystal, pairs of N-HÁ Á ÁS hydrogen bonds link the molecules into centrosymmetric dimers.
The work was supported by the Natural Science Foundation of Zhejiang Province, China (No. M203027).

Comment
Hydrazone and its derivatives have shown the potential application in the biological field (Okabe et al., 1993;Hu et al., 2001). As part of the ongoing investigation on anti-cancer compounds, the title compound has recently been prepared in our laboratory and its crystal structure is presented here.
In the molecules, the benzene ring and dithiocarbazate fragment are located on the opposite sides of the C═N bond, showing the E-configuration. This agrees with those found in the structures reported previously (Shan et al., 2008a,b). The dithiocarbazate fragment is approximately planar, the r.m.s deviation being 0.0281 Å; its mean plane is oriented with respect to the benzene ring at 11.38 (15)°, similar to that found in a related structure (Shan et al. 2008c). In the crystal structure, intermolecular N-H···S hydrogen bonding links molecules to form the centro-symmetric dimers (Table 1).

Experimental
Methyl dithiocarbazate was synthesized as described previously by Hu et al. (2001). Methyl dithiocarbazate (0.24 g, 2 mmol) and 2-bromo-4,5-dimethoxybenzaldehyde (0.49 g, 2 mmol) were dissolved in ethanol (20 ml), then acetic acid (0.2 ml) was added to the ethanol solution with stirring. The mixture solution was refluxed for 6 h. After cooling to room temperature, microcrystals appeared. The microcrystals were separated from the solution and washed with cold water three times. Recrystallization was performed twice with absolute methanol to obtain colourless single crystals of the title compound.

Refinement
H atoms were placed in calculated positions with C-H = 0.93-0.96 Å and N-H = 0.86 Å, and refined in riding mode with U iso (H) = 1.5U eq (C) for methyl H atoms and 1.2U eq (C,N) for the others. Fig. 1. The molecular structure of the title compound with 40% probability displacement (arbitrary spheres for H atoms).