Suffixes carbonitrile

Cyclic nitriles are named by adding the suffix carbonitrile to the name of the ring system to which the -CN group is attached. 

For acids that are named as alkanecarboxylic acids, the corresponding nitriles are named by using the suffix -carbonitrile. The —C=N group can also be named as a substituent, the cyano group. 

Acyclic nitriles are named by adding -nitrile as a suffix to the alkane name that includes the carbon atom of the nitrile. The carbon atom of the nitrile is C-1. Cyclic compounds with the —CN group bonded to the ring are named using the suffix -carbonitrile. The ring carbon bearing the cyano group is C-1, but that number is not included in the name. 

The suffixes -oic acid, -al, -amide and -nitrile are used to name acyclic compounds having one or two characteristic groups. Locants are not necessary, as these groups must be at the end of a chain. The suffixes -carboxylic acid, -carbaldehyde, -carboxamide and -carbonitrile are used when more than two groups are attached to chains or one or more groups are attached to cycles. 

Aldehydes and nitriles may also be named as such when the corresponding acid has a trivial name, e.g., acetaldehyde, benzonitrile. The alternative method is to add -al or -nitrile as sufi x to the hydrocarbon name, giving ethanal (=acetaldehyde) or ethane-nitrile ( = acetonitrile) in this system the C of the OHO or -CN group is included in the name of the parent and not in the suffix, so the system cannot be used when -CHO or is attached directly to a ring system. In the latter type of case -CHO is denoted by carbaldehyde and -CH by carbonitrile, giving, e.g., cyclohexanecarbaldehyde or phenanthrene-2-carbo-nitrile. 

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