Ethyl 1-[2-(morpholin-4-yl)ethyl]-2-[4-(morpholin-4-yl)phenyl]-1H-1,3-benzimidazole-5-carboxylate

The asymmetric unit of the title compound, C26H32N4O4, consists of two independent molecules. In both molecules, the ethoxy groups are each disordered over two sets of sites with occupancies of 0.695 (4):0.305 (4) and 0.877 (2):0.123 (2). The dihedral angles between the benzimidazole ring system and the adjacent benzene ring in the two molecules are 41.41 (5) and 31.46 (5)°. In the crystal, molecules are linked by C—H⋯O and C—H⋯N interactions.

The asymmetric unit of the title compound, C 26 H 32 N 4 O 4 , consists of two independent molecules. In both molecules, the ethoxy groups are each disordered over two sets of sites with occupancies of 0.695 (4):0.305 (4) and 0.877 (2):0.123 (2). The dihedral angles between the benzimidazole ring system and the adjacent benzene ring in the two molecules are 41.41 (5) and 31.46 (5) . In the crystal, molecules are linked by C-HÁ Á ÁO and C-HÁ Á ÁN interactions.

Comment
The benzimidazole nucleus is an important heterocyclic ring because of its synthetic utility and broad range of pharmacological activities. Benzimidazole derivatives exhibit different pharmacological effects, including antifungal. In recent years, attention has increasingly been given to the synthesis of benzimidazole derivatives as a source of new antimicrobial agents (Vijaya et al., 2009). Recent observations suggest that substituted benzimidazoles and heterocyclic, which are the structural isosters of nucleotides owing to the fused heterocyclic nuclei in their structures that allow them to interact easily with the biopolymers, possess potential activity with lower toxicities in the chemotherapeutic approach in man (Haugwitz, 1982;Hisano, 1982).

Experimental
Ethlyl-3-amino-4-(morpholinoethylamino) benzoate (0.01 mol) and sodium metabisulfite adduct of 4-morpholino benzaldehyde (0.01 mol) were dissolved in DMF. The reaction mixture was refluxed at 130 °C for 4 hrs. After completion, the reaction mixture was diluted in ethyl acetate (20 mL) and washed with water (20 mL). The organic layer was collected, dried over Na 2 SO 4 and the evaporated in vacuo to yield the product. The product was recrystallized from ethyl acetate.

Refinement
The ethoxy group was disordered over two position with the refined occupancies of 0.695 (4):0.305 (4) and 0.877 (2):0.123 (2). The same U ij parameters were applied to the C19Y/C19B pair. Similarity restraints were used on the disordered part of the molecular structure. All H-atoms were positioned geometrically and refined using a riding model, with C-H = 0.95-0.99 Å, and with U iso (H) = 1.2U eq (C) or 1.5U eq (C methyl ).     Glazer, 1986) operating at 100.0 (1) K.
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.