When there are three or more substituents on a benzene ring they are located by numbering the ring so as to give the substituents the lowest possible numbers, keeping in mind the highest priority group will be at carbon atom 1.
Examples of simply multisubstituted benzene:
Compound Name | Line Drawing | 3D Model |
1,3,5-tribromobenzene | ![]() |
![]() ![]() |
1-chloro-2-methyl-4-propylbenzene | ![]() |
![]() ![]() |
1,2,3,5-tetramethylbenzene | ![]() |
![]() ![]() |
If there is a common name for one or more of the substituents on the benzene ring, the one with the higher priority is used as the root name for the compound and the other substituent is named as a prefix. Since the highest priority group is located at carbon 1 in the ring it does not need a number to specify its location.
Examples of common names for multisubstituted benzene:
Compound Name | Line Drawing | 3D Model |
3,5-dimethylphenol | ![]() |
![]() ![]() |
2,4,6-trimethylbenzoic acid | ![]() |
![]() ![]() |
3-bromo-4-methylbenzenesulfonic acid | ![]() |
![]() ![]() |
ethyl 2,4-dimethylbenzoate | ![]() |
![]() ![]() |
There are a number of common names for multisubstituted benzene rings.
Examples are:
Compound Name | Line Drawing |
mesitylene | ![]() |
picric acid | ![]() |