Three examples of acyl groups having specific names were noted earlier. These are often used in common names of compounds. In the following examples the IUPAC names are color coded, and common names are given in parentheses.
• Esters: The alkyl group is named first, followed by a derived name for the acyl group, the oic or ic suffix in the acid name is replaced by ate.
e.g. CH3(CH2)2CO2C2H5 is ethyl butanoate (or ethyl butyrate).
Cyclic esters are called lactones. A Greek letter identifies the location of the alkyl oxygen relative to the carboxyl carbonyl group.
• Acid Halides: The acyl group is named first, followed by the halogen name as a separate word.
e.g. CH3CH2COCl is propanoyl chloride (or propionyl chloride).
• Anhydrides: The name of the related acid(s) is used first, followed by the separate word "anhydride".
e.g. (CH3(CH2)2CO)2O is butanoic anhydride & CH3COOCOCH2CH3 is ethanoic propanoic anhydride (or acetic propionic anhydride).
• Amides: The name of the related acid is used first and the oic acid or ic acid suffix is replaced by amide (only for 1º-amides).
e.g. CH3CONH2 is ethanamide (or acetamide).
2º & 3º-amides have alkyl substituents on the nitrogen atom. These are designated by "N-alkyl" term(s) at the beginning of the name.
e.g. CH3(CH2)2CONHC2H5 is N-ethylbutanamide; & HCON(CH3)2 is N,N-dimethylmethanamide (or N,N-dimethylformamide).
Cyclic amides are called lactams. A Greek letter identifies the location of the nitrogen on the alkyl chain relative to the carboxyl carbonyl group.
• Nitriles: Simple acyclic nitriles are named by adding nitrile as a suffix to the name of the corresponding alkane (same number of carbon atoms).
Chain numbering begins with the nitrile carbon . Commonly, the oic acid or ic acid ending of the corresponding carboxylic acid is replaced by onitrile.
A nitrile substituent, e.g. on a ring, is named carbonitrile.
e.g. (CH3)2CHCH2C≡N is 3-methylbutanenitrile (or isovaleronitrile).