Loading VerChem
Preparing your chemistry tools...
Preparing your chemistry tools...
Also known as: Beckmann Reaction
Discovered by Ernst Otto Beckmann (1886)
Rearrangement of a ketoxime to an amide (or lactam from cyclic ketoximes). The group anti to the hydroxyl migrates to nitrogen. Industrially important: cyclohexanone oxime → caprolactam (nylon-6 precursor).
Protonation or activation of the oxime OH, making it a good leaving group (H₂O).
The alkyl group anti to the departing OH migrates from carbon to nitrogen as water leaves. This is a concerted 1,2-shift.
Anti group migrates — stereospecific
Water attacks the nitrilium ion, followed by tautomerization to give the amide product.
Nitrilium → amide via hydration
Cyclohexanone oxime
H₂SO₄ (fuming), heat
ε-Caprolactam (→ Nylon-6)
Acetophenone oxime
PCl₅, then H₂O
N-Phenylacetamide (acetanilide)
Converts ketones to amides (via oxime). Industrially essential for Nylon-6 production. Also useful for ring expansion in synthesis.