What does heterocycle mean?
A heterocycle is a cyclic compound whose ring includes atoms from more than one chemical element. In organic chemistry, it usually means a carbon-based ring containing at least one heteroatom, such as nitrogen, oxygen, or sulfur, alongside its carbon atoms. The term is especially common in discussions of pharmaceuticals, natural products, and aromatic organic compounds, since many biologically important molecules contain heterocyclic rings. Related forms include the adjective heterocyclic and the regular plural heterocycles. Although heterocycle can describe the ring structure itself, it also refers more broadly to the whole compound containing that structure. The word contrasts with carbocycle, which names a ring composed entirely of carbon atoms.
nounA cyclic compound whose ring contains two or more different kinds of atoms, usually carbon together with one or more heteroatoms such as nitrogen, oxygen, or sulfur.
- A cyclic compound or ring structure containing atoms of two or more different elements.
"The molecule contains a five-membered heterocycle that is central to its biological activity."
"This reaction forms a heterocycle from several simpler organic molecules."
"Many pharmaceuticals contain a heterocycle that strongly binds to a particular receptor."
The regular plural is used when referring to multiple heterocyclic compounds or ring structures.
"Several heterocycles were screened for potential biological activity."
A heterocycle is a circle with a diverse cast: usually carbon sharing the ring with nitrogen, oxygen, or sulfur.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does heterocycle come from?
The word was formed in the nineteenth century from the combining form hetero-, derived from Greek heteros, meaning “different,” and cycle, from Greek kyklos, meaning “circle.” Its development followed the growth of organic chemistry and the need to distinguish mixed-element rings from all-carbon rings. The same Greek roots underlie words such as heterogeneous and cyclic.
Related word forms
How heterocycle is actually used
This is primarily specialist vocabulary in organic chemistry, medicinal chemistry, and materials science. In general use, heterocycle refers to the compound or ring itself, while heterocyclic is normally used as an adjective.
Easily confused with heterocycle
A heterocycle contains atoms of different elements in its ring, whereas a carbocycle has an all-carbon ring.
Heterocycle is the noun naming the compound or ring, while heterocyclic is the adjective describing it.