Theme XVIII: Heterocycles

Heteroclyclic compounds

General characteristics and classification of heterocyclic compounds. Heteroatoms. Furan, Piran, Indole, Adenine, Imidazole, Thiazole.

General characteristics and classification of heterocyclic compounds

As said before (see introduction to heterocycles), heterocyclic compounds have at least one different element called carbon heteroatom in its ring.

They are classified according to the number of atoms in the ring:

Pentagonal - 5 atoms

Example

Furan

Hexagonal - 6 atoms

Example

Piran

With condensed nucleus.
Fusion of two heterocyclic rings or a heterocyclic ring and a benzene ring:

Examples

The heteroatoms that can be present in the heterocyclic compounds are nitrogen, oxygen and sulfur.

There are heterocyclic compounds in which 2 or 3 heteroatoms are present.
The heteroatoms contained in the ring may be the same (imidazole) or different (thiazole).

see also

Introduction to heteroclycles
Pentagonal heterocyclic compounds with one heteroatom
Pyrrole
Porphyrin. Porphyrin ring
Chlorophyll

Hexagonal heterocyclic compounds: The Pyran and Pyrimidine

Pyrimidine ring
Indole, tryptophan, indole-3-acetic acid
Purine, uric acid, adenine, guanine.
Structure of nucleic acids