# Carboxylic Acid Derivatives

Carboxylic acid derivatives include acid halides, acid anhydrides, esters, amides, and nitriles. Acid halides have the ending -oyl followed by the name of the halide, such as chloride. Anhydrides have the ending -oic anhydride, esters have a prefix for the alkyl group and the ending -oate, and nitriles have the ending -nitrile.

#### Derivatives of Carboxylic Acid

Acid halides are named by substituting -yl for -ic, followed by the name of the halide.

#### Examples of Acid Halides

An acid anhydride is an organic compound that contains two carbonyl groups (${\rm {C{=}O}}$) bound to the same oxygen atom with (RCO)2O stoichiometry. To name acid anhydrides, replace acid with anhydride. If the molecule has different acyl groups, they should be listed in alphabetical order.

#### Examples of Acid Anhydrides

An ester is an organic compound that contains a carboxyl unit in which a hydroxyl group is replaced by an alkyl or aryl group, giving it ${\rm{R{-}C({=}O)OR}'}$ or ${\rm{R{-}COOR}'}$ stoichiometry. Ester derivatives of carboxylic acids are given two names. The first name denotes the alkyl group attached to the sp3-hybridized oxygen; the second name indicates the carboxylic acid. Then -ate is substituted for -ic or -oic.

#### Examples of Esters

An amide is an organic compound that contains a carbonyl (${\rm{C{=}O}}$) linked to a nitrogen atom through a ${ \rm{C{-}N}}$ bond. It has a general ${ \rm{RC({=}O)NRR}'}$ stoichiometry. To name an amide, substitute the -oic or -ic acid with -amide. Substituents located on the N are indicated by an N in the name.

#### Examples of Amides

A nitrile is an organic compound that has a carbon triple bonded to a nitrogen with RCN stoichiometry; it is also called a cyano group. To name nitriles, substitute -onitrile or -nitrile for the -ic or -oic acid suffix. Nitriles are also commonly referred to by their common names, which may include cyanide.