Page 17 - Org 3 theoritical book 2024-25

Clinical Pharmacy PharmD - 2024/2025 Level 2 Pharmaceutical Organic Chemistry-3 (PC 305)
Nomenclature of Heterocyclic Compounds

1. Trivial name (common name)

A- Heterocyclic compounds containing one heteroatom:

1) Unsaturated heterocyclic compounds (aromatic/ not aromatic compounds):

Numbering begins with the heteroatom (priority is O, S, then N) and goes in a

direction so as to give substituents the lowest number possible.

2) Saturated heterocyclic compounds:

B- Heterocyclic compounds containing two or more heteroatoms:

Numbering begins with the heteroatom (priority is O, S, then N) and goes in a
direction so as to give substituents (or other heteroatoms) the lowest possible number.