8-{[3-(3-Methoxyphenyl)-1,2,4-oxadiazol-5-yl]methoxy}quinoline monohydrate

In the title hydrate, C19H15N3O3·H2O, the three aromatic groups in the quinoline derivative are close to coplanar: the central oxadiazole fragment makes dihedral angles of 15.7 (2)° with the benzene ring and 5.30 (14)° with the quinoline ring system. In the crystal, the organic molecules are connected with water molecules by pairs of O—H⋯N hydrogen bonds involving the quinoline and oxadiazole N atoms. The molecules form stacks along the a axis, neighboring molecules within each stack being related by inversion and the shortest distance between the centroids of the oxadiazole and pyridine rings being 3.500 (2) Å. Molecules from neighboring stacks are linked by weak C—H⋯O hydrogen bonds, forming a three-dimensional structure.

In the title hydrate, C 19 H 15 N 3 O 3 ÁH 2 O, the three aromatic groups in the quinoline derivative are close to coplanar: the central oxadiazole fragment makes dihedral angles of 15.7 (2) with the benzene ring and 5. 30 (14) with the quinoline ring system. In the crystal, the organic molecules are connected with water molecules by pairs of O-HÁ Á ÁN hydrogen bonds involving the quinoline and oxadiazole N atoms. The molecules form stacks along the a axis, neighboring molecules within each stack being related by inversion and the shortest distance between the centroids of the oxadiazole and pyridine rings being 3.500 (2) Å . Molecules from neighboring stacks are linked by weak C-HÁ Á ÁO hydrogen bonds, forming a three-dimensional structure.

Experimental
The title  to acetone (20 ml), and then the mixture was heated to reflux for 6 hours, cooled to room temperature, filtered and evaporated to afford the yellow solid. The crude product was recrystallized from ethyl acetate. Yield 2 g (80.5%).
Crystals suitable for X-ray analysis were obtained by slow evaporation of an ethanol solution.

Refinement
H atoms were positioned geometrically, with C-H = 0.93, 0.97 and 0.96 Å for aromatic, methylene and methyl H, respectively, and constrained to ride on their parent atoms, with U iso (H) = xU eq (C,N), where x = 1.5 for methyl H and x = 1.2 for all other H atoms. In the absence of significant anomalous dispersion effects, 1739 Friedel pairs were merged.  The molecular structure of the title compound with the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level.

Figure 2
A packing diagram of the title compound viewed down the c axis. Dashed lines indicate intermolecular C-H···O interactions.

Special details
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 > 2sigma(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.