Naming compounds with substituents
1
3-ethylhexane
2
3-ethylpentan-1-ol
3-ethylhexane
2
3-ethylpentan-1-ol
The longest carbon chain may not be all on the same line on the page.
In the alkane 1 the longest chain has six carbon atoms. If you have difficulty seeing this, move your mouse over the image.
The name is based on the longest chain containing the functional group.
In the alcohol 2 the longest chain containing the functional group has five carbon atoms. Move your mouse over the image to see that the alternate chain also has five carbons.
In the alkane 1 the longest chain has six carbon atoms. If you have difficulty seeing this, move your mouse over the image.
The name is based on the longest chain containing the functional group.
In the alcohol 2 the longest chain containing the functional group has five carbon atoms. Move your mouse over the image to see that the alternate chain also has five carbons.
Any atom or group of atoms replacing H at a carbon is called a substituent.
- Substituents on the longest chain are included in the name as prefixes. Common substituents are in the lists below.
bromo Br chloro Cl methyl CH3 ethyl CH3CH2 phenyl C6H5
Compounds 1 and 2 both have an ethyl substituent. Note that saturated hydrocarbon substituents have the same name as the parent alkane with the -ane at the end of the name substituted by -yl.
- The functional group in the compound determines the numbering of the chain.In a haloalkane, the halogen substituent has the lowest possible number.
For alkanes the substituent has the lowest possible number.