Amines are organic compouns and functional groups that contain a basic nitrogen atom with a lone pair. Amines are derivatives of ammonia, wherein one or more hydrogen atoms are replaced by organic substituents such as alkyl and aryl groups. Compounds with the nitrogen atom next to a carbonyl of the structure R-C(=O)NR2 are called amides and have different chemical properties. Important amines include amino acids, biogenic amines, trimethylamine (fish smell), and aniline; see Category:Amines for a list of amines.