In organic chemistry, an amide,[1][2][3] also known as an organic amide or a carboxamide, is a compound with the general formula R−C(=O)−NR′R″, where R, R', and R″ represent any group, typically organyl groups or hydrogen atoms.[4][5] The amide group is called a peptide bond when it is part of the main chain of a protein, and an isopeptide bond when it occurs in a side chain, as in asparagine and glutamine. It can be viewed as a derivative of a carboxylic acid (R−C(=O)−OH) with the hydroxyl group (−OH) replaced by an amine group (−NR′R″); or, equivalently, an acyl (alkanoyl) group (R−C(=O)−) joined to an amine group.
Common of amides are formamide (H−C(=O)−NH2), acetamide (H3C−C(=O)−NH2), benzamide (C6H5−C(=O)−NH2), and dimethylformamide (H−C(=O)−N(−CH3)2). Some uncommon examples of amides are N-chloroacetamide (H3C−C(=O)−NH−Cl) and chloroformamide (Cl−C(=O)−NH2).
Amides are qualified as primary, secondary, and tertiary according to whether the amine subgroup has the form −NH2, −NHR, or −NRR', where R and R' are groups other than hydrogen.[5]