Classification of Heterocyclic Compounds

Heterocycles are cyclic compounds in which one or more atoms of the ring are hetero atoms like O, N, S, P, etc. They are present in many biologically important molecules such as alkaloids, essential amino acids, vitamins, hemoglobin, nucleic acids, and hormones. Heterocyclics are also present in a large number of synthetic drugs like caffeine, acyclovir (antiviral), clopidogrel (anti-platelet), diazepam, carbamazepine (anti-epileptic), nicotine, etc. There are six main classification of heterocyclic compounds

Classification of Heterocyclic Compounds

These heterocycles may be classified on the basis of the number of atoms present in the ring. For example,

1. Five membered heterocyclic rings containing one heteroatom:

2. Five membered heterocyclic rings containing two heteroatoms (1, 2 – azoles):

1. Pyrazole: X = N – H
2. Isoxazole: X = O
3. Isothiazole: X = S

3. Five membered heterocyclic rings containing two heteroatoms (1, 3 – azoles):

1. Imidazole: X = N – H (Azole)
2. Oxazole: X = O (Oxa)
3. Thiazole: X = S (Thia)

4. Six membered heterocyclic rings containing one heteroatom:

5. Six membered heterocyclic rings containing two heteroatoms:

6. Polyclinic heterocyclic rings:

Make sure you also check our other amazing Article on : Stereoselective and Stereospecific Reactionsa