Ethyl 2-[2-(4-hydroxy-3-methoxybenzylidene)hydrazin-1-ylidene]-3,4-dimethyl-2,3-dihydro-1,3-thiazole-5-carboxylate

The title compound, C16H19N3O4S, is almost planar, with a dihedral angle of 2.88 (9)° between the mean planes of the benzene and thiazole rings. The molecule adopts an E conformation about the two C=N bonds, with a C—N—N—C torsion angle of −177.01 (11)°. An intramolecular C—H⋯O hydrogen bond exists between a thiazole methyl group and the formic acid ethyl ester carbonyl O atom. In the crystal, molecules are linked by O—-H⋯O hydrogen bonds, forming chains propagating along [2-10]. The chains are linked via C—H⋯O hydrogen bonds with R 2 2(12) ring motifs, forming sheets lying parallel to (12-2). The sheets are further linked through out-of-plane C—H⋯N hydrogen bonds with R 2 2(12) ring motifs and C—H⋯π interactions, forming an interesting three-dimensional supramolecular architecture.

The title compound, C 16 H 19 N 3 O 4 S, is almost planar, with a dihedral angle of 2.88 (9) between the mean planes of the benzene and thiazole rings. The molecule adopts an E conformation about the two C N bonds, with a C-N-N-C torsion angle of À177.01 (11) . An intramolecular C-HÁ Á ÁO hydrogen bond exists between a thiazole methyl group and the formic acid ethyl ester carbonyl O atom. In the crystal, molecules are linked by O--HÁ Á ÁO hydrogen bonds, forming chains propagating along [210]. The chains are linked via C-HÁ Á ÁO hydrogen bonds with R 2 2 (12) ring motifs, forming sheets lying parallel to (122). The sheets are further linked through out-of-plane C-HÁ Á ÁN hydrogen bonds with R 2 2 (12) ring motifs and C-HÁ Á Á interactions, forming an interesting three-dimensional supramolecular architecture.
In the crystal, an interesting supramolecular architecture is formed as the molecules link up to form sheets in plane (1 2 -2) through both C-H···O R 2 2 (12) ring motifs (Bernstein et al., 1995) and O-H···O interactions. These sheets are further linked through out-of-plane C-H···N R 2 2 (12) ring motifs and C-H···π interactions (Table 1 and Fig. 2).

Experimental
The title compound was synthesized according to the published procedure (Er et al., 2009). Crystals were grown by slow evaporation of a 1 3-dichloro-2-propanol solution.

Refinement
The H atoms were placed in calculated positions and refined in the riding mode: O-H = 0.84 Å, C-H = 0.95-0.98 Å with U iso (H) = 1.5U eq (C) for methyl H atoms and = 1.2U eq (O,C) for other H atoms.

Computing details
Data collection: CrysAlis PRO (Agilent, 2011); cell refinement: CrysAlis PRO (Agilent, 2011); data reduction: CrysAlis PRO (Agilent, 2011); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008  The crystal packing of the title compound, viewed along the a axis. Hydrogen bonds are shown as dashed lines -see Table 1 for details.  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.