What is the Difference Between Imidazole and Triazole

The main difference between imidazole and triazole is that imidazole is a heterocyclic organic compound containing two nitrogen atoms separated by a carbon atom in a five-membered ring, called 1,3-diazole whereas triazole is either of two isomeric heterocyclic compounds having a five-membered ring with three nitrogen atoms and two double bonds in the ring.

In general, imidazole and triazole are two analogous organic compounds with a heterocyclic ring structure. Both have carbon and nitrogen bonds in the ring structure. In the pharmaceutical industry, both compounds are important as antifungal drugs.

Key Areas Covered

1. What is Imidazole
   • Definition, Characteristics, Importance
2. What is Triazole
   • Definition, Characteristics, Importance
3. Similarities Between Imidazole and Triazole
   • Outline of Common Features
4. Difference Between Imidazole and Triazole
   • Comparison of Key Differences

Key Terms

Imidazole, Triazole

What is Imidazole

Imidazole is an organic compound with the formula C₃N₂H₄. It is a white or colorless solid, soluble in water, producing a mildly alkaline solution. In chemistry, imidazole is an aromatic heterocycle, classified as a diazole, and has non-adjacent nitrogen atoms in meta-substitution.

Figure 1: Imidazole

Furthermore, many natural products such as alkaloids, contain an imidazole ring. Usually, imidazoles share the 1,3-C₃N₂ ring but feature varied substituents. More importantly, this ring system is present in important biological building blocks, such as histidine and the related hormone histamine. Many drugs contain an imidazole ring, such as certain antifungal drugs, the nitroimidazole series of antibiotics, and the sedative midazolam.

What is a Triazole

Triazole is a heterocyclic compound with the molecular formula C₂H₃N₃, featuring a five-membered ring of two carbon atoms and three nitrogen atoms. The main feature of triazoles is their substantial isomerism, depending on the positioning of the nitrogen atoms within the ring.

Figure 2: Triazole

Moreover, many triazoles are versatile, biologically active compounds. They are commonly used as fungicides and plant retardants. Triazoles’ ability to react as azides is important in bioorthogonal chemistry because of the large number of nitrogen atoms in them. Lastly, the many free lone pairs in triazoles make them useful as coordination compounds, although not typically as haptic ligands.

Similarities Between Imidazole and Triazole

• Imidazole and triazole are two analogous organic compounds with carbon and nitrogen heterocyclic rings.
• They also have five-membered ring structures.
• Moreover, both are important in the pharmaceutical industry as antifungal drugs.

Difference Between Imidazole and Triazole

Definition

Imidazole is a heterocyclic organic compound containing two nitrogen atoms separated by a carbon atom in a five-membered ring, called 1,3-diazole whereas triazole is either of two isomeric heterocyclic compounds having a five-membered ring with three nitrogen atoms and two double bonds in the ring.

Chemical Formula

The chemical formula of imidazole is C₃N₂H₄ while the chemical formula of triazole is C₂H₃N₃.

Number of Nitrogen Atoms

Usually, imidazole contains two nitrogen atoms in the heterocyclic ring while triazole contains three nitrogen atoms in the heterocyclic ring.  

Adjacent Nitrogen Atoms

Imidazole contains non-adjacent nitrogen atoms while triazole contains two adjacent nitrogen atoms in the ring structure.

Occurrence

Moreover, the imidazole ring occurs in many natural products such as alkaloids while triazole is a versatile, biologically active compound commonly used as fungicides and plant retardants.

Conclusion

In brief, imidazole and triazole are two heterocyclic organic compounds with nitrogen atoms in the aromatic ring structure. Usually, two non-adjacent nitrogen atoms occur in the imidazole while three nitrogen atoms occur in the heterocyclic ring of the triazole. Both imidazole and triazole are important in the pharmaceutical industry. However, the main difference between imidazole and triazole is their number of nitrogen atoms in the heterocyclic ring structure.

References:

1. Verma, A., Joshi, S., & Singh, D. (2013, October 31). Imidazole: Having versatile biological activities. Journal of Chemistry. Retrieved September 6, 2022.
2. Matin, M. M., Matin, P., Rahman, M. R., Ben Hadda, T., Almalki, F. A., Mahmud, S., Ghoneim, M. M., Alruwaily, M., & Alshehri, S. (1AD, January 1). Triazoles and their derivatives: Chemistry, synthesis, and therapeutic applications. Frontiers. Retrieved September 6, 2022.

Image Courtesy:

1. “Imidazole 2D numbered” By Jynto – Own Work (CC0) via Commons Wikimedia
2. “Triazole” By Claudio Pistilli – Own Work (CC BY-SA 4.0) via Commons Wikimedia