N-Methyl-2-(1-methyl-3-phenylprop-2-en-1-ylidene)hydrazinecarbothioamide

In the title compound, C12H15N3S, the molecule deviates slightly from planarity, with a maximum deviation from the mean plane of the non-H atoms of 0.2756 (6) Å for the S atom and a torsion angle for the N—N—C—N fragment of −7.04 (16)°. In the crystal, molecules are linked by N—H⋯S hydrogen-bond interactions, forming centrosymmetric dimers. Additionally, one weak intramolecular N—H⋯N hydrogen-bond interaction is observed. The crystal packing shows a herringbone arrangement viewed along the c axis.

In the title compound, C 12 H 15 N 3 S, the molecule deviates slightly from planarity, with a maximum deviation from the mean plane of the non-H atoms of 0.2756 (6) Å for the S atom and a torsion angle for the N-N-C-N fragment of À7.04 (16) . In the crystal, molecules are linked by N-HÁ Á ÁS hydrogen-bond interactions, forming centrosymmetric dimers. Additionally, one weak intramolecular N-HÁ Á ÁN hydrogen-bond interaction is observed. The crystal packing shows a herringbone arrangement viewed along the c axis.

Comment
Thiosemicarbazone derivatives have a wide range of biological properties. For example, some thiosemicarbazones similar to the title compound show antifungal activity (Nishimura et al., 1979). As part of our study on synthesis and structural chemistry of thiosemicarbazone derivatives from natural products, we report herein the crystal structure of a derivative of the essential oil of cinnamon bark (benzylideneacetone, a methyl derivative of the cinnamaldehyde).
In the crystal structure of the title compound the central N-N-C-N unit is not planar with an torsion angle along N1-N2-C10-N3 of -7.04 (16)° and the maximum deviation from the mean plane of the non-H atoms amounting to 0.2756 (6) Å for S1. The molecule, shows a trans conformation at the C7-C8 and N1-N2 bonds (Fig. 1).
In the crystal the molecules are linked by N-H···S hydrogen bonds interactions forming centrosymmetric dimers.
Additionally, one weak N-H···N intramolecular H-interaction is observed.The crystal packing shows a herringbone arrangement viewed along the c-axis. (Fig. 3).

Experimental
Starting materials were commercially available and were used without further purification. The title compound synthesis was adapted to a procedure reported previously (Freund & Schander, 1902). The hydrochloric acid catalyzed reaction, a mixture of benzylideneacetone (10 mmol) and 4-methyl-3-thiosemicarbazide (10 mmol) in ethanol (80 ml) was refluxed for 5 h. After cooling and filtering, the title compound was obtained. Crystals suitable for X-ray diffraction were obtained in ethanol by the slow evaporation of solvent.

Refinement
All hydrogen atoms were localized in a difference density Fourier map. Their positions and isotropic displacement parameters were refined.  The molecular structure of the title compound with labeling and displacement ellipsoids drawn at the 50% probability level.  Crystal structure of the title compound viewed along the c-axis. The herringbone pattern of the crystal packing along the a-axis is observed.

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.