Basic IUPAC Organic Nomenclature

IUPAC Nomenclature

IUPAC nomenclature uses the longest continuous chain of carbon atoms to determine the basic root name of the compound.
The root name is then modified due to the presence of different functional groups which replace hydrogen or carbon atoms in the parent sturcture.

There are a number of different ways to modify the root name to indicate the functional groups present.

• Substitutive : (most common) : the highest priority functional group modifies the suffix of the root name, while all other groups, or substituents, are added as prefixes to the root name.
• Functional group : names the compound based on the highest priority functional group, i.e. as an alcohol, ketone, alkyl halide, etc.
• Replacement : used to indicate when an atom, usually carbon, is replaced by another atom.
• Conjunctive : used to combine named subunits (i.e. cyclohexanecarboxylic acid).
• Common or trivial : due to widespread use, some compunds with simple names have been adopted into basic IUPAC nomenclature.

These pages focus primarily on the substitutive and functional group nomenclature but also include examples of all systems in cases where the name is generated by a combination of methods.

Remember:

• that organic molecules can in general be either chains (also known as acyclic) or cyclic or a combination of both. In most cases this doesn't make a difference.  The general rules for cyclic systems will be developed for cycloalkanes and can be applied to other scenarios.
• molecules are not restricted to a single functional group, they can have several functional groups. A common example are amino acids which have both an amine and a carboxylic acid present.