Amines are organic compounds that contain nitrogen atoms with a lone pair of electrons. They are derived from ammonia (NH₃) by replacing one or more hydrogen atoms with alkyl or aryl groups. Amines are important reagents for chemical synthesis because they can participate in various reactions such as nucleophilic substitution, addition, elimination, reduction and rearrangement.

Amines are versatile reagents for chemical synthesis because they can act as nucleophiles, bases, ligands and catalysts in various reactions. Some examples of reactions involving amines are:

• Alkylation of aromatic rings by Friedel-Crafts reaction. Aromatic amines can act as Lewis bases and coordinate with Lewis acids such as AlCl₃ to form electrophilic complexes that can react with benzene rings to form alkylated products.
• Formation of amides by reaction with carboxylic acids or acid derivatives. Amines can act as nucleophiles and attack the carbonyl carbon atom of carboxylic acids or their derivatives such as esters, acid chlorides or anhydrides to form amides. Amides are important functional groups in organic chemistry and biochemistry because they can form peptide bonds between amino acids.
• Formation of diazonium salts by reaction with nitrous acid. Primary aromatic amines can react with nitrous acid (HNO₂) at low temperatures to form diazonium salts (Ar-N2+X-) which are highly reactive intermediates that can undergo various coupling reactions with phenols, anilines, aliphatic amines and other nucleophiles to form azo compounds. Azo compounds are brightly colored substances that are used as dyes and pigments.