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Nomenclature Summary / Group Priority

This section contains the basic IUPAC rules for nomenclature and a table of functional groups in priority order, with examples.

For a complete introduction to organic nomenclature : Basic IUPAC Organic Nomenclature

Naming branched chain alkanes (the IUPAC way....)

Naming the parent chain:

Here is a list of the root names for the hydrocarbon chains of C1 to C12 and a few other biologically important chains:

Functional Groups and Priorities:

Here is a list of important functional groups arranged in decreasing priority order. All the structures can be manipulated using JMOL

This priority order is important in nomenclature as the higher priority group is the principle functional group and it is typically numbered such that is has the lowest number (the locant). 

You need to learn to recognise these functional groups not just for nomenclature but in order to recognise their reactions later.
In each case the fundamental functional group unit is shown, it is this that you need to be able to recognise - pay attention to the atoms involved and the bonding patterns.

Functional
Group

Formula

Structure

Carboxylic Acids

Acid Anhydrides

Esters

Acyl Halides

Amides

Nitriles

Aldehydes

Ketones

Alcohols

Thiols

Amines

Ethers

Sulphides

Alkenes

Alkynes

Alkyl Halides

Nitro

Alkanes


 


© Dr. Ian Hunt, Department of Chemistry, University of Calgary