(E)-4-Methoxy-N′-[(6-methyl-4-oxo-4H-chromen-3-yl)methylidene]benzohydrazide monohydrate

In the title hydrate, C19H16N2O4·H2O, the 4H-chromen-4-one segment is slightly twisted, with a dihedral angle between the two six-membered rings of 3.30 (5)°. The dihedral angles between the plane of the pyranone ring and the hydrazide plane and between the planes of the pyranone ring and the benzene ring of the p-methoxybenzene unit are 26.69 (4) and 2.23 (3)°, respectively. The molecule is connected to the solvent water molecule by an N—H⋯O hydrogen bond. In the crystal, there are π–π stacking interactions between centrosymmetrically related pyranone rings [centroid–centroid distance = 3.5394 (9) Å], as well as bridges formed by the water molecules via O—H⋯O hydrogen bonds.

In the title hydrate, C 19 H 16 N 2 O 4 ÁH 2 O, the 4H-chromen-4-one segment is slightly twisted, with a dihedral angle between the two six-membered rings of 3.30 (5) . The dihedral angles between the plane of the pyranone ring and the hydrazide plane and between the planes of the pyranone ring and the benzene ring of the p-methoxybenzene unit are 26.69 (4) and 2.23 (3) , respectively. The molecule is connected to the solvent water molecule by an N-HÁ Á ÁO hydrogen bond. In the crystal, there arestacking interactions between centrosymmetrically related pyranone rings [centroidcentroid distance = 3.5394 (9) Å ], as well as bridges formed by the water molecules via O-HÁ Á ÁO hydrogen bonds.

Related literature
For the biological activity of related compounds, see: Khan et al. (2009);Tu et al. (2013). For related structures, see: Ishikawa & Watanabe (2014a,b Table 1 Hydrogen-bond geometry (Å , ). We acknowledge the University of Shizuoka for instrumental support.

Comment
Schiff base derivatives of 3-formyl chromones have attracted much attention due to their biological functions such as enzyme inhibition (Khan et al. 2009;Tu et al. 2013). We herein report the crystal structure of the title compound, which was obtained from the condensation reaction of 6-methyl-3-formylchromone with 4-methoxybenzoylhydrazide in benzene.
The 4H-chromen-4-one segment segment is slightly twisted with a dihedral angle between the two 6-membered rings of 3.30 (5)°. The dihedral angles between the pyranone ring and the hydrazide plane (C11/N1/N2/C12) and between the pyranone ring and the benzene ring of the p-methoxybenzene unit are 26.69 (4) and 2.23 (3)°, respectively. The molecule is connected to the solvent water molecule byan N-H···O hydrogen bond.

Experimental
4-Methoxybenzoylhydrazide (1.00 mmol), 6-methyl-3-formylchromone (1.00 mmol), and a few drops of acetic acid were dissolved in 25 mL of benzene and the mixture was refluxed with a Dean-Stark apparatus for 6 h. After cooling, the precipitates were collected, washed with n-hexane, and dried (yield 68.9% 337.119, found 337.194. Single crystals suitable for X-ray diffraction were obtained by slow evaporation of an N,N-dimethylformamide solution of the title compound at room temperature.

Refinement
The C(sp 2 )-and N(sp 2 )-bound hydrogen atoms were placed in geometrical positions [C-H 0.95 Å, U iso (H) = 1.2U eq (C), N-H 0.88 Å, U iso (H) = 1.2U eq (N)], and refined using a riding model. Hydrogen atoms of methyl groups were found in a difference Fourier map, and a rotating group model was applied with distance constraint [C-H = 0.98 Å, U iso (H) = 1.2U eq (C)]. Hydrogen atoms of the water molecule were found in a difference Fourier map, and were refined using a riding model.  The molecular structure of the title compound, with displacement ellipsoids drawn at the 50% probability level.
Hydrogen atoms are shown as small spheres of arbitrary radius.

Figure 2
A crystal packing view of the title compound. Intermolecular N-H···O and O-H···O hydrogen bonds are represented by dashed lines.

Data collection
Rigaku AFC-7R diffractometer ω-2θ scans 4581 measured reflections 3748 independent reflections 3219 reflections with F 2 > 2σ(F 2 ) R int = 0.008 Special details Refinement. Refinement was performed using all reflections. The weighted R-factor (wR) and goodness of fit (S) are based on F 2 . R-factor (gt) are based on F. The threshold expression of F 2 > 2.0 σ(F 2 ) is used only for calculating R-factor (gt).