Nitroimidazole

5-Nitroimidazole^[1]

Names
IUPAC name 5-Nitro-1H-imidazole
Identifiers
CAS Number	100214-79-7
ChemSpider	10637918
Jmol interactive 3D	Image
PubChem	18208
InChI InChI=1S/C3H3N3O2/c7-6(8)5-2-1-4-3-5/h1-3H Key: KUNMIWQQOPACSS-UHFFFAOYSA-N InChI=1/C3H3N3O2/c7-6(8)5-2-1-4-3-5/h1-3H Key: KUNMIWQQOPACSS-UHFFFAOYAV
SMILES c1cn(cn1)[N+](=O)[O-]
Properties
Chemical formula	C3H3N3O2
Molar mass	113.07 g/mol
Melting point	303 °C (577 °F; 576 K) (decomposes)
Hazards
Main hazards	Xn
R-phrases	R20/21/22 R36/37/38
S-phrases	S26 S36/37
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

5-Nitroimidazole is an organic compound with the formula O₂NC₃H₂N₂H. It is the most common isomer of imidazole containing one nitro group. The term nitroimidazole also refers to a class of antibiotics that share similar chemical structures.^[2]

Synthesis

Imidazole reacts with a mixture of nitric acid to give 5-nitroimidazole:

C₃H₃N₂H + HNO₃ → O₂NC₃H₂N₂H + H₂O

Under conventional conditions for nitration, the reaction is conducted in the presence of sulfuric acid.

Nitroimidazole antibiotics

From the chemistry perspective, nitroimidazole antibiotics can be classified according to the location of the nitro functional group. 4- and 5-nitroimidazole are equivalent from the perspective of drugs since these tautomers readily interconvert. Drugs of the 5-nitro variety include metronidazole, tinidazole, nimorazole, dimetridazole, 6-Amino PA824, ornidazole, megazol, and azanidazole. Drugs based on 2-nitromidazoles include benznidazole and pimonidazole.

Nitroimidazole antibiotics have been used to combat anaerobic bacterial and parasitic infections.<ref name=Mital2009">Mital A (2009). "Synthetic Nitroimidazoles: Biological Activities and Mutagenicity Relationships". Sci Pharm 77 (3): 497–520. doi:10.3797/scipharm.0907-14.</ref> Perhaps the most common example is metronidazole (Flagyl). Other heterocycles such as nitrothiazoles (thiazole) are also used for this purpose. Nitroheterocycles may be reductively activated in hypoxic cells, and then undergo redox recycling or decompose to toxic products.^[3]

Three nitroimidazoles: metronidazole, tinidazole, and nimorazole

References

1. 4-Nitroimidazole at Sigma-Aldrich
2. Edwards, David I. "Nitroimidazole drugs - action and resistance mechanisms. I. Mechanism of action" Journal of Antimicrobial Chemotherapy 1993, volume 31, pp. 9-20. doi:10.1093/jac/31.1.9.
3. Juchau, MR (1989). "Bioactivation in chemical teratogenesis". Annu. Rev. Pharmacol. Toxicol. 29: 165–167. doi:10.1146/annurev.pa.29.040189.001121. PMID 2658769.