1-(2-Methyl-5-nitro-1H-imidazol-1-yl)propan-2-yl acetate

In the title compound, C9H13N3O4, an ester of the anti-infection drug secnidazole, the dihedral angle between the nitroimidazole mean plane (r.m.s. deviation = 0.028 Å) and the pendant acetate group is 43.17 (11)°. In the crystal, inversion dimers linked by pairs of C—H⋯O interactions generate R 2 2(10) loops and further C—H⋯O hydrogen bonds link the dimers into [100] chains. Weak aromatic π–π stacking interactions with a centroid–centroid distance of 3.7623 (11) Å are also observed.

In the title compound, C 9 H 13 N 3 O 4 , an ester of the antiinfection drug secnidazole, the dihedral angle between the nitroimidazole mean plane (r.m.s. deviation = 0.028 Å ) and the pendant acetate group is 43.17 (11) . In the crystal, inversion dimers linked by pairs of C-HÁ Á ÁO interactions generate R 2 2 (10) loops and further C-HÁ Á ÁO hydrogen bonds link the dimers into [100] chains. Weak aromaticstacking interactions with a centroid-centroid distance of 3.7623 (11) Å are also observed.

Comment
The title compound (I) is an ester derivative of well known 5-nitroimidazole drug i.e secnidazole. The worthwhile use of nitroimidazole derivatives is in the treatment of diseases caused by protozoa and anaerobic bacteria (Mital, 2009).
Members of nitroimidazole drugs are pronounced in thier wide-range activities and in addition during their use the rate of resistance in anaerobes is still very low (Edwards, 1993). Antiprotozoal and bactericidal properties of nitroimidazoles are associated with their aromatic nitro group. The Secnidazole like chemotherapeutic agents inhibit the growth of both anaerobic bacteria and some anaerobic protozoa (Crozet et al. 2009).

Experimental
The title compound was synthesized by adding acetic anhydride (1.2 ml, 12.70 mmol)to a hot (70 °C) stired solution of secnidazole (2 g m, 10.8 mmol) in pyridine (2 ml) and toluene (10 ml). The reaction mixture was further processed to refluxed for 5 hrs, cooled, treated with water and then organic phase was evaporated to obtain solid product which was recrystallized from chloroform and toluene solution to yield greenish plates in 81% yield.

Refinement
The hydrogen atoms are positioned at their calculated positions geometrically with C-H = 0.9300 Å, 0.9600 Å, 0.9700 Å, 0.9800 Å for aromatic, methyl, methylen, and methin H respectively. These are constrained to ride on their parent atoms during subsequent refinement with U iso (H) = 1.2U eq (C) for methyl, and U iso (H) = 1.5 eq (C) for rest of the H atoms.

Computing details
Data collection: SMART (Bruker, 2000); cell refinement: SAINT (Bruker, 2000); data reduction: SAINT (Bruker, 2000); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008), PARST (Nardelli, 1995) and PLATON (Spek, 2009     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 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.