Amides

An amide contains the group −CONH−: a carbonyl group, C=O, bonded directly to a nitrogen atom.OCR recognises two types:• a primary amide, RCONH₂, where the nitrogen carries two hydrogen atoms, e.g. ethanamide, CH₃CONH₂
• a secondary amide, RCONHR', where one hydrogen on the nitrogen has been replaced by an alkyl (or aryl) group, e.g. CH₃CONHCH₃Amides are made from acyl chlorides, which are very reactive. An acyl chloride reacts with ammonia to make a primary amide, and with a primary amine to make a secondary amide. In each case HCl is also formed, which reacts with a second molecule of ammonia or amine to give a salt:CH₃COCl + 2NH₃ → CH₃CONH₂ + NH₄ClCH₃COCl + 2CH₃NH₂ → CH₃CONHCH₃ + CH₃NH₃ClWorked example: to make CH₃CH₂CONHCH₂CH₃, split the molecule at the C−N bond. The acyl part, CH₃CH₂CO−, comes from propanoyl chloride; the N part comes from ethylamine.The amide link, −CONH−, is the same link that joins monomers in polyamides and joins amino acids in proteins (where it is called a peptide link).