amine

Any of a class of organic chemical compounds in which one or more of the hydrogen atoms of ammonia (NH₃) have been replaced by other groups of atoms.

Depending on the number of hydrogens replaced by an organic molecule, one distinguishes between primary, secondary, and tertiary amines. All three types tend to be stronger bases than ammonia, with secondary amines the strongest. The NH₂ functionality of a primary amine is called an amino group, while the NH of secondary amines is known as an imino group.

Both groups can take part in a number of characteristic chemical reactions. For instance, the amino group can react with a carboxylic acid to form an amide bond. An important example of this bond type is the peptide bond which holds proteins and other polypeptides (see peptide) together, fusing the carboxylic acid group of one amino acid with the amino group of the next.

Methyl amines have unpleasant ammonia odours and occur in decomposing fish. They are all gases at ordinary temperature.

Aromatic amine compounds include aniline, which is used in dyeing.