2-[1-(2-Hydroxy-3-methoxybenzyl)-1H-benzimidazol-2-yl]-6-methoxyphenol monohydrate

The asymmetric unit of the title compound, C22H20N2O4·H2O, comprises a substituted benzimidazole molecule and a water molecule of crystallization. The dihedral angles between the benzimidazole ring system and the two outer benzene rings are 16.54 (4) and 86.13 (4)°. The dihedral angle between the two hydroxy-substituted benzene rings is 82.20 (5)°. In the crystal structure, intermolecular O—H⋯O hydrogen bonds, involving the hydroxy groups and water molecules, form R 4 4(8) ring motifs, and link symmetry-related molecules into extended chains along the c axis. The crystal structure is further stabilized by weak intermolecular C—H⋯O hydrogen bonds, weak C—H⋯π and π–π stacking [centroid–centroid = 3.6495 (6)–3.7130 (6) Å] interactions. Intramolecular O—H⋯O and O—H⋯N interactions are also present.

The asymmetric unit of the title compound, C 22 H 20 N 2 O 4 ÁH 2 O, comprises a substituted benzimidazole molecule and a water molecule of crystallization. The dihedral angles between the benzimidazole ring system and the two outer benzene rings are 16.54 (4) and 86.13 (4) . The dihedral angle between the two hydroxy-substituted benzene rings is 82.20 (5) . In the crystal structure, intermolecular O-HÁ Á ÁO hydrogen bonds, involving the hydroxy groups and water molecules, form R 4 4 (8) ring motifs, and link symmetry-related molecules into extended chains along the c axis. The crystal structure is further stabilized by weak intermolecular C-HÁ Á ÁO hydrogen bonds, weak C-HÁ Á Á andstacking [centroid-centroid = 3.6495 (6)-3.7130 (6) Å ] interactions. Intramolecular O-HÁ Á ÁO and O-HÁ Á ÁN interactions are also present.

Comment
Many benzimidazoles are pharmaceutical agents and are used widely in biological system applications which enable important synthetic strategies in drug discovery. Phenolic and anisolic benzimidazole derivatives have been synthesized and evaluated for vasodilator and antihypertensive activity , while other alkyloxyaryl benzimidazole derivatives have been tested for the spasmolytic activity . Latif et al. have developed the reactions of some phenolic aldehydes with o-phenylenediamine in great details and managed to isolate the title compound (Latif et al., 1983).
In view of the above, we have obtained the title compound (I), derived from benzimidazole and a bis-Schiff base compound and have determined its crystsal structure herein.

Experimental
The synthetic method has been described earlier (Al-Douh et al., 2006, 2007, while the single crystals suitable for X-ray diffraction were obtained by evaporation of a methanol solution of (I) at 353 K.

Refinement
H atoms of the hydroxy groups were positioned by a freely rotating O-H bond and constrained with a fixed distance of 0.82 Å. The water H-atoms were located from the difference Fourier map and refined freely. The rest of the H atoms were positioned geometrically and refined with a riding model approximation with C-H = 0.95-0.98 and U iso (H) = 1.2 or 1.5 U eq (C). A rotating group model was used for the methyl groups.