Heterocyclic compound
Heterocyclic compounds are substances which contain a ring structure as found in
benzene and the aromatic compounds, or aromatic hydrocarbons, but in which other atoms than
carbon, such as
sulfur,
oxygen or
nitrogen are found as part of the ring. Some examples are
pyridine (C
5H
5N) and
pyrimidine (C
4H
4N
2).
Note that compounds such as cyclopropane, an anaesthetic with explosive properties, and cyclohexane, a solvent are not heterocyclic, they are merely cycloalkanes. The suffix '-cyclic' implies a ring structure, while 'hetero' refers to an atom other than carbon, as above.