Lactam

A lactam is a cyclic amide, formally derived from an amino alkanoic acid through cyclization reactions.

Lactams form from cyclic ketones and hydrazoic acid in the Schmidt reaction.

[1] Lactams form from intramolecular attack of linear acyl derivatives from the nucleophilic abstraction reaction.

[2] Lactams form by copper-catalyzed 1,3-dipolar cycloaddition of alkynes and nitrones in the Kinugasa reaction Diels-Alder reaction between cyclopentadiene and chlorosulfonyl isocyanate (CSI) can be utilized to obtain both β- as well as γ-lactam.

[4] A lactim is a cyclic imidic acid compound characterized by an endocyclic carbon-nitrogen double bond.

From left to right, the above are general structures of β-lactam , a γ-lactam , a δ-lactam , and ε-lactam . Their common names are β-propiolactam, γ-butyrolactam, δ-valerolactam, and ε-caprolactam.
Lactam                                                 Lactim