2-Chloromethyl-1-methyl-1,3-benzimidazole

The title compound, C9H9ClN2, was prepared from the reaction of N-methylbenzene-1,2-diamine and 2-chloroacetic acid in boiling 6 M hydrochloric acid. The benzimidazole unit is approximately planar, the largest deviation from the mean plane being 0.008 (1) Å. The Cl atom is displaced by 1.667 (2) Å from this plane. The methyl group is statistically disordered with equal occupancy.

The title compound, C 9 H 9 ClN 2 , was prepared from the reaction of N-methylbenzene-1,2-diamine and 2-chloroacetic acid in boiling 6 M hydrochloric acid. The benzimidazole unit is approximately planar, the largest deviation from the mean plane being 0.008 (1) Å . The Cl atom is displaced by 1.667 (2) Å from this plane. The methyl group is statistically disordered with equal occupancy.

Comment
Benzimidazole and its derivatives are present in various bioactive compounds possessing antiparasitic, antimicrobial, and antifungal properties (Refaat, 2010;Laryea et al., 2010;Horton et al., 2003;Ries et al., 2003;Spasov et al., 1999;Matsui et al. 1994). They also play very important role in the synthesis of many natural products and synthetic drugs. Compounds possessing the benzimidazole moiety express significant activity against several viruses such as HIV (Porcari, et al., 1998;Rath, et al., 1997), Herpes (HSV-1) (Migawa, et al., 1998), human cytomegalovirus (HCMV) and influenza. As a part of our ongoing investigations of benzimidazole derivatives, the title compound was synthesized and its crystal structure is reported herein.
The two fused rings forming the benzimidazole moiety are planar with the largest deviation from the mean plane being 0.008 (1)Å. The Cl atom is out of this plane by -1.667 (2)Å (Fig. 1). The methyl group is statistically disordered. The distances and angles within the methyl-benzimidazole agree with the values reported in the literature (43 hits found in the Cambridge Structural Database, Conquest, version 1.13; Allen, 2002).
The packing is only stabilized by electrostatic and van der Waals interactions.

Experimental
For the preparation of the title compound N-methylbenzene-1,2-diamine (5.0 mmol) and 2-chloroacetic acid(6.0 mmol) was dissolved in 6 N hydrochloric acid (30.0 ml) and refluxed for 6 h. The reaction mixture was cooled in to room temperature, then neutralized with aqueous sodium hydroxide. The precipitate was filtered off and washed with cold water. The crude product was crystallized from ethanol to give white block-like crystals of the title compound.

Refinement
All H atoms were fixed geometrically and treated as riding with C-H = 0.96 Å (methyl), 0.97 Å (methylene) and 0.93 Å (aromatic) with U iso (H) = 1.2U eq (C, aromatic or methylene) and U iso (H) = 1.5U eq (C, methyl). Fig. 1. The asymmetric unit of (1) with the atom-labelling scheme. Displacement ellipsoids are drawn at the 30% probability level. H atoms are represented as small spheres of arbitrary radii. 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 > σ(F 2 ) is used only for calculating Rfactors(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.

Figures
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )