Lactam

A lactam (the noun is a portmanteau of the words lactone + amide) is a cyclic amide. Prefixes may indicate the ring size: β-lactam (4-membered), γ-lactam (5-membered), δ-lactam (6-membered ring). That order in the nomenclature is because beta β, gamma γ and delta δ are the second, third and fourth letters in the alphabetical order of the Greek alphabet, respectively.

Synthesis
General synthetic methods exist for the organic synthesis of lactams.
 * Lactams form by the acid-catalyzed rearrangement of oximes in the Beckmann rearrangement.
 * Lactams form from cyclic ketones and ammonia in the Schmidt reaction.
 * lactams form from cyclisation of amino acids.
 * In iodolactamization an iminium ion reacts with an halonium ion formed in situ by reaction of an alkene with iodine.
 * [[Image:Iodolactamization.png|700px|Iodolactamization reaction]]


 * Lactams form by copper catalyzed 1,3-dipolar cycloaddition of alkynes and nitrones in the Kinugasa reaction

Reactions

 * Lactams can polymerize to polyamides.