Azole

Azoles are a class of five-membered heterocyclic compounds containing an nitrogen atom and at least one other non-carbon atom (i.e. nitrogen, sulfur, or oxygen) as part of the ring.^[1] Their names originate from the Hantzsch–Widman nomenclature. The parent compounds are aromatic and have two double bonds; there are successively reduced analogs (azolines and azolidines) with fewer. One, and only one, lone pair of electrons from each heteroatom in the ring is part of the aromatic bonding in an azole. Names of azoles maintain the prefix upon reduction (e.g., pyrazoline, pyrazolidine). The numbering of ring atoms in azoles starts with the heteroatom that is not part of a double bond, and then proceeds towards the other heteroatom.

Imidazole and other five-membered aromatic heterocyclic systems with two nitrogens are extremely common in nature and form the core of many biomolecules

Compound classes

• 

  Pyrazole

• 

  Imidazole

• 

  1,2,3-Triazole

• 

  1,2,4-Triazole

• 

  Tetrazole

• 

  Pentazole

• 

  Oxazole

• 

  Isoxazole

• 

  Oxadiazole
  (1,2,4-Oxadiazole)

• 

  Thiazole

• 

  Isothiazole

• 

  Thiadiazole
  (1,2,3-Thiadiazole)

References

This article incorporates material from the Citizendium article "Azole", which is licensed under the Creative Commons Attribution-ShareAlike 3.0 Unported License but not under the GFDL.

1. Eicher, T.; Hauptmann, S. (June 2003). The Chemistry of Heterocycles: Structure, Reactions, Synthesis, and Applications (2nd ed.). John Wiley & Sons. ISBN 3527307206.

External links

• Azoles at the US National Library of Medicine Medical Subject Headings (MeSH)
• Nomenclature, IUPAC