This document discusses IUPAC nomenclature rules for naming organic compounds. It explains that the longest carbon chain is identified as the parent name, such as hexane for a 6-carbon chain. Substituents on the chain are identified and listed alphabetically, such as chloro and methyl groups. The substituents are prefixed with numbers indicating their position on the carbon chain, such as 3-chloro-3,4-dimethylhexane. Examples of correctly named organic compounds are also provided.

1. IUPAC NOMENCLATURE
S15A, Semester 2
March 2016
By Punia Turiman

2. IUPAC NOMENCLATURE
Let us name this organic compound as an
example.
Cl H
CH3 - CH2 - C – C - CH2 -CH3
CH3CH3

3. How to name organic compounds?
• Find the longest carbon chain. How many
carbon atoms does it have? six.
Thus its parent name : hexane.
• Identify all substituents /branches in the
chain.
• Name these substituents : chloro, methyl.
• Place these in alphabetical order : e.g. chloro,
ethyl, methyl . c,e,m.

4. Naming organic compounds
• If more than one group of a particular type is
present, use prefixes di, tri, tetra, penta etc
(neglect these in alphabetical process!)
e.g. dimethyl, look at m not di.
• No the C atoms in sequence in the longest
chain from the end nearest a branch (give the
lowest no to the substituents) & number the
f.g with the lowest no.

5. Naming organic compunds
• Prefix each substituent by a no showing its
position of attachment to the longest chain
e.g. 3-chloro-3,4-dimethyl instead of 3,4,4.
• Place a dash (hypen) between a no & name.
Place a comma between numbers. Write the
name as one word.
e.g. 3-chloro-3,4-dimethylhexane.

6. More examples
a.
3-methyl-3-pentanol
b. NH2
CH3 - C - CH2 – CH2 - CH3 2-aminopentane
H
OH
CH3 - CH2 - C – CH2 - CH3
CH3

7. Have fun !
Learning organic chemistry