The Beckmann rearrangement is a reaction that converts oximes to amides. Specifically, it is the acid-catalyzed transformation of a ketoxime to an N–substituted amide. This rearrangement occurs in the presence of strong acids like sulfuric acid or acid chlorides, and can be applied to oximes of both aryl and alkyl ketones as well as cyclic ketoximes. However, aldoximes typically undergo dehydration to form nitriles instead of amides under Beckmann rearrangement conditions.

1. Beckmann rearrangement
What is Beckmann Rearrangement?
The Beckmann rearrangement is a reaction employed in many sectors to convert oximes
to amides.
The acid-catalyzed transformation of a ketoxime to N–substituted amide is known as
the Beckmann Rearrangement.
The rearrangement occurs in the presence of a range of acids, including strong acids like
H2SO4, Polyphosphoric acid, and acid chlorides like SOCl2, RCOCl, and RSO2Cl. The reaction
may be applied to the oximes of both aryl and alkyl ketones and cyclic ketoximes.
Aldoximes, on the other hand, normally suffer dehydration to nitriles (RCH = NOH –> RCN)
under the condition of the Beckmann rearrangement, and examples of the formation of
formamides (HCONHR) from aldoximes are rare.
Depending on the starting material, it could also produce nitriles from aldehydes

2. Beckmann Rearrangement reaction