Ethyl 1-(2-hydroxyethyl)-2-(4-methoxyphenyl)-1H-benzimidazole-5-carboxylate monohydrate

In the title molecule, C19H20N2O4·H2O, the benzimidazole ring system is essentially planar [maximum deviation = 0.013 (11) Å] and is inclined to the 4-methoxyphenyl ring by 30.98 (5)°. In the crystal, O—H⋯O and O—H⋯N hydrogen bonds involving the water molecule link neighbouring molecules, forming a two-dimensional network lying parallel to the bc plane. There are also C—H⋯π and π–π interactions present. The latter involve inversion-related benzimidazole rings with centroid–centroid distances of 3.5552 (8) and 3.7466 (8) Å.

In the title molecule, C 19 H 20 N 2 O 4 ÁH 2 O, the benzimidazole ring system is essentially planar [maximum deviation = 0.013 (11) Å ] and is inclined to the 4-methoxyphenyl ring by 30.98 (5) . In the crystal, O-HÁ Á ÁO and O-HÁ Á ÁN hydrogen bonds involving the water molecule link neighbouring molecules, forming a two-dimensional network lying parallel to the bc plane. There are also C-HÁ Á Á andinteractions present. The latter involve inversion-related benzimidazole rings with centroid-centroid distances of 3.5552 (8) and 3.7466 (8) Å .

D-HÁ
The title compound, (Fig. 1), is a benzimidazole derivative and is similiar to the p-tolyl derivative, ethyl 1-(2-hydroxylethyl)-2-p-tolyl-1H-benzimidazole-5-carboxylate, reported on by (Arumugam et al., 2010). The title compound is associated with one water molecule of crystallization. The bond lengths (Allen et al., 1987) and angles are in normal ranges and are comparable to those reported for the p-tolyl derivative mentioned above. The benzimidazole ring (N1/N2/C7-C13) is essentially planar with a maximum deviation of 0.013 (11) Å for atom C12. The phenyl ring is inclined at an angle of 30.98 (5)° to the benzimidazole mean plane.

Experimental
The title compound was prepared according to the method described by Arumugam et al. (2010). Colourless block-like crystals of the title compound, suitable for X-ray diffraction analysis, were obtained by slow evaporation of a solution of the title compound in EtOAc

Refinement
The water and the hydroxy H-atoms were located from difference Fourier map and were freely refined. The C-bound H atoms were included in calculated positions and refined using a riding model: C-H = 0.93, 0.96 and 0.97 Å, for CH, CH 3 and CH 2 H-atoms, respectively, with U iso (H) = k x U eq (C), where k = 1.5 for CH 3 H-atoms and k = 1.2 for all other H atoms. A rotating group model was applied to the methyl groups.
supplementary materials sup-2 Figures Fig. 1. The molecular structure of the title compound, with the atom numbering and displacement ellipsods drawn at the 40% probability level.