Guided IUPAC Naming

First identify the principal functional group (this determines the suffix). Then find the longest carbon chain or ring containing that group (the parent). Identify all substituents as prefixes. Finally, number the chain to give the functional group the lowest locant, then substituents the lowest locants.

The first step is identifying the principal characteristic group (functional group) of the molecule. This group determines the suffix of the name: -ol for alcohols, -al for aldehydes, -one for ketones, -oic acid for carboxylic acids, -amine for amines, -ene for alkenes, and -yne for alkynes.

The parent chain must contain the principal functional group. Among chains that include the FG, choose the longest one. If there is a tie, prefer the chain with the most multiple bonds, then the most substituent attachment points.

Number the chain so the principal functional group gets the lowest possible locant. If there is a tie, give the lowest locants to multiple bonds (double/triple), then to substituent prefixes. If still tied, the alphabetically first substituent gets the lower number.