2-[1-(2-Hydroxy-4-methoxyphenyl)ethylidene]-N-methylhydrazinecarbothioamide

In the title compound, C11H15N3O2S, the dihedral angle between the mean planes of the benzene ring and hydrazinecarbothioamide group is 9.2 (1)°. An intramolecular O—H⋯N hydrogen bond is observed, serving to maintain an approximately planar conformation for the molecule. In the crystal, inversion dimers linked by C—H⋯O interactions occur. Further C—H⋯O contacts link dimers into (010) chains.

In the title compound, C 11 H 15 N 3 O 2 S, the dihedral angle between the mean planes of the benzene ring and hydrazinecarbothioamide group is 9.2 (1) . An intramolecular O-HÁ Á ÁN hydrogen bond is observed, serving to maintain an approximately planar conformation for the molecule. In the crystal, inversion dimers linked by C-HÁ Á ÁO interactions occur. Further C-HÁ Á ÁO contacts link dimers into (010) chains.

Related literature
For the synthesis and structure of thiosemicarbazones as ligands, see: Lobana et al. (2009Lobana et al. ( , 2012. For palladium complexes with thiosemicarbazone ligands, see: Chellan et al. (2010). For related structures, see: Anderson et al. (2012Anderson et al. ( , 2013. For bond lengths, see: Allen et al. (1987).  Table 1 Hydrogen-bond geometry (Å , ).  Thiosemicarbazones are a versatile class of ligands that can adopt multiple modes of binding to a metal (Lobana, et al., 2009) and the synthesis and structure determination of these metal complexes is an active area of research. (Lobana, et al., 2012) Palladium complexes with thiosemicarbazone ligands have been shown to have a variety of biological activity including anti-fungal and anti-tumor activity. (Chellan, et al., 2010). We have previously reported the structure of two analogous novel thiosemicarbazones (Anderson, et al., 2012;Anderson, et al., 2013). Here, we report the synthesis and crystal structure of a novel thiosemicarbazone ligand, (I), C 11 H 15 N 3 O 2 S .

Experimental
In (I), the dihedral angle between the mean planes of the benzene ring and hydrazinecarbothioamide group (N1/N2/C8/S1/N3) is 9.2 (1)° (Fig. 1). Bond lengths are in normal ranges (Allen et al., 1987). In the crystal, an intramolecular O-H···N hydrogen bond is observed serving to keep the molecule in a nearly planar conformation.
Additional weak and C-H···O intermolecular interactions (Table 1) assist in linking the molecules into dimers along (010) and influence crystal packing (Fig. 2).

Experimental
A 50 mL round bottom flask was charged with 0.218 g (1.31 mmol) of 2′-hydroxy-4′-methoxyacetophenone, 0.138 g (1.31 mmol) of 4-methyl-3-thiosemicarbazide, dissolved in 20 mL of methanol. The resulting colorless solution was refluxed for 48 hours and then a drop of concentrated HCl was added and the solution was refluxed for an additional 48 hours. The resulting yellow solution was transferred to a 125 mL separatory funnel. Dichloromethane (10 mL) and water (10 mL) were added, and the organic layer was separated. The aqueous layer was extracted with an additional 10 mL of dichloromethane. The organic layers were combined, washed with brine (2 x 10 mL), dried with magnesium sulfate, and the solvent was removed in vacuo to give a yellow solid (Fig. 3). The solid was dissolved in hot acetonitrile, allowed to cool to room temperature and then stored at 273 K resulting in colorless crystals (58 mg, 18%) after 24 hours. M.p.