1-(2-Methyl-5-nitro-1H-imidazol-1-yl)acetone

In the molecule of the title compound, C7H9N3O3, the nitro and carbonyl groups are tilted with respect to the imidazole ring by 9.16 (6) and 65.47 (7)°, respectively. Neighbouring chains are linked via C—H⋯N and C—H⋯O hydrogen bonds forming two-dimensional slab-like networks lying parallel to (01-1).

The title compound is a derivative of secnidazole obtained during our attempts to make more effective structure analogues of this important antibacterial drug.

Experimental
Periodic acid (2.8 mmol, 0.64 g), pyridinium chlorochromate (PCC, 4 mol%) were suspended in acetonitrile (20 ml) and stirred vigorously for five minutes. The mixture was allowed to cool on an ice-salt bath followed by the addition of secnidazole (2.7 mmol, 0.50 g) and allowed to stir for 36 h at ambient temperature. After the completion of the reaction [TLC analysis], the reaction mixture was washed with brine/water (1:1 v/v), saturated aqueous Na 2 SO 3 solution, dried (Na 2 SO 4 ) and filtered. The filtrate was evaporated in vacuum to afford off-white crystals which were washed and recrystalized by dissolving in petroleum ether to obtained colorless crystals of the title compound (0.32 g, 64% yield) found suitable for single-crystal X-ray diffraction analysis.

Refinement
H atoms of methyl, methylene and methine carbon atoms were positioned geometrically with C-H = 0.93-0.96 Å and constrained to ride on their parent atoms with U iso (H)= 1.2U eq (C) or 1.5U eq (C) for methyl H atoms. A rotating group model was applied to the methyl group.   The molecular structure of the title compound with displacement ellipsoids drawn at 30% probability level.

Figure 2
The crystal packing of the title compound. Intermolecular hydrogen bonds are shown as dashed lines.

Experimental
Periodic acid (2.8 mmol, 0.64 g), pyridinium chlorochromate (PCC, 4 mol%) were suspended in acetonitrile (20 ml) and stirred vigorously for five minutes. The mixture was allowed to cool on an ice-salt bath followed by the addition of secnidazole (2.7 mmol, 0.50 g) and allowed to stir for 36 h at ambient temperature. After the completion of the reaction [TLC analysis], the reaction mixture was washed with brine/water (1:1 v/v), saturated aqueous Na 2 SO 3 solution, dried (Na 2 SO 4 ) and filtered. The filtrate was evaporated in vacuum to afford off-white crystals which were washed and recrystalized by dissolving in petroleum ether to obtained colorless crystals of the title compound (0.32 g, 64% yield) found suitable for single-crystal X-ray diffraction analysis.

Refinement
H atoms of methyl, methylene and methine carbon atoms were positioned geometrically with C-H = 0.93-0.96 Å and constrained to ride on their parent atoms with U iso (H)= 1.2U eq (C) or 1.5U eq (C) for methyl H atoms. A rotating group model was applied to the methyl group. The molecular structure of the title compound with displacement ellipsoids drawn at 30% probability level.