IUPAC Nomenclature with Functional Groups
A functional group is an atom or group of atoms which is responsible for characteristic properties of a compound.
Mono-functional Derivatives
The derivatives of hydrocarbons containing only one functional group are called monofunctional derivatives. Most of the IUPAC names of functional derivatives of hydrocarbons are derived by replacing the suffix aneof the parent alkane (corresponding to the number of carbonatoms in the longest chain) by a specificsuffixfor the functional groups.
There are some derivatives in which a particular prefix is added to the parent alkane name as in nitroalkanes, haloalkanes, and haloarenes.
Rule 1
First of all, the longest chain of carbon atoms containing the functional group is identified. In case of carbon containing functional group, (–CHO, –COOH) the main chain must include the carbon atom of the group.
Rule 2
The longest continuous carbon atom chain is numbered from that end which will give the lowest number to the carbon atom bearing the functional group.
Rule 3
There is a specific suffix for each functional group that replaces the ending -e in the name of the corresponding parent alkane.
Rule 4
If the carbon chain is branched, then the attached alkyl groups are named and numbered.
Rule 5
While writing the name of the compound, place the substituents in the alphabetical order.
Functional Groups
Some Common Functional Groups and their Aliphatic Derivatives
| Functional Group | Suffix / Prefix | General Name |
| -OH (Hydroxyl) | -ol | Alkanol (Alcohol) |
| -COOH (Carboxyl) | -oic acid | Alkanoic acid |
| -SO3H (Sulphonic) | Alkylsulphonic acid | |
| -CHO (Aldehydic) | -al | Alkanal |
| >CO (Ketonic) | -one | Alkanone |
| -CONH2 (Amide) | -amide | Alkanamide |
| -COX (Carboxyl halide) | -oyl halide | Alkanoyl halide |
| -COO- (Ester) | -oate | Alkyl alkanoate |
| -CN (Cyano) | -nitrile | Alkanenitrile |
| -SH (Thiol) | -thiol | Alkanethiol |
| -NH2 (Amino) | -amine | Alkanamine |
| -O- (Ether) | -oxy | Alkoxyalkane |
| -X | Halo- | Haloalkane |
| -NO2 (Nitro) | Nitro- | Nitroalkane |
Compounds with more than one functional group
In case of organic compounds containing more than one functional group, one group is given preference over the others in deciding the parent compound. The priority order of the various functional groups is as follows:
–COOH, –COOR, –SO3H, –COX, –CONH2, –CHO, –CO–, –CN, –OH, –SH, –O–, –NH2, –X (halogen), –NO2, –C=C–, and –C≡C–