A heterocyclic compound is a cyclic
compound that has atoms of at least two
different elements as members of its ring(s).
The counterparts of heterocyclic compounds
are homocyclic compounds, the rings of
which are made of a single element.
Although heterocyclic compounds may be
inorganic, most contain at least one carbon
atom, and one or more atoms of elements
other than carbon within the ring structure,
such as sulfur, oxygen, or nitrogen.
Classification based on electronic structure
With heterocycles containing five atoms, the
unsaturated compounds are frequently more stable
because of aromaticity.
i.e - Puran,, Pyrrole,Thiphene etc
Puran, It is an aromatic compound.
Because it has Resonance structure.
It is also a aromatic compound.
It show aromaticity in its structure.
Synthesis of Pyrrole:
Pyrrole can be synthesized from
Pyrole ring is acidic.
Pyrrol donate proton in reaction for this
reason,it is acidic in nature.
Chemical Reaction of Pyrrole .
It gives Electrophilic substitution reaction
Six-membered rings with a single heteroatom
i.e – Pyridine
Synthesis of pyridine:
Chemical reaction of Pyridine
-Electrophilic Substitution reaction of
Benzofuse ring such as Indole ring, Quinoline
ring, Isoquinoline ring.
Leigngruber-Batcho indole synthesis
Fisher indole synthesis
Oxidation of indole
Due to the electron-rich nature of indole, it
is easily oxidized. Simple oxidants such as N-
bromosuccinimide will selectively oxidize
indole 1 to oxindole (4 and 5).