In general, if the atoms that make up the ring contain heteroatoms, such rings become heterocycles, and organic compounds containing heterocycles are called heterocyclic compounds. An article called Stability-indicating assay for azathioprine and 6-mercaptopurine by reversed-phase high-performance liquid chromatography, published in 1979-12-30, which mentions a compound: 4897-25-0, Name is 5-Chloro-1-methyl-4-nitroimidazole, Molecular C4H4ClN3O2, Recommanded Product: 4897-25-0.
A rapid method based on reversed-phase high-performance liquid chromatog. is described for the separation and quantitation of azathioprine (I) [446-86-6], 6-mercaptopurine (II) [50-44-2] and their potential contaminants and degradants present in dosage forms. Procedures based on simple dissolution or extraction in 0.02 M NaOH give quant. precision of 1% relative standard deviation at the macro-level and 2% relative standard deviation for the microassay of analytes. The method is stability-indicating and was used for preliminary studies of the degradation of I in 0.9% NaCl injection, subjected to thermal or UV irradiation treatment. The content uniformity of dosage forms of I and II was measured. Only I injection as the freeze-dried Na salt [55774-33-9] contained detectable amounts of contaminants 1-methyl-4-nitro-5-chloroimidazole [4897-25-0] and hypoxanthine [68-94-0].
Although many compounds look similar to this compound(4897-25-0)Recommanded Product: 4897-25-0, numerous studies have shown that this compound(SMILES:C1=NC(=C(Cl)[N]1C)[N+]([O-])=O), has unique advantages. If you want to know more about similar compounds, you can read my other articles.
Reference:
Nitrile – Wikipedia,
Nitriles – Chemistry LibreTexts