Theme XVIII: Heterocycles
General characteristics and
classification of heterocyclic compounds. Heteroatoms. Furan, Piran, Indole, Adenine, Imidazole, Thiazole.
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
Hexagonal - 6 atoms
With condensed nucleus.
Fusion of two heterocyclic rings or a heterocyclic ring and a benzene ring:
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).