The Beckmann rearrangement is an acid-catalyzed reaction that converts ketoximes to amides. It was discovered by German chemist Ernst Otto Beckmann in the late 19th century. This rearrangement can occur in both cyclic and acyclic compounds, converting ketoximes to lactams or amides, respectively. Common reagents used to catalyze the Beckmann rearrangement include concentrated sulfuric acid, hydrochloric acid, and phosphorus pentachloride. The reaction proceeds through the formation of a nitrilium ion intermediate followed by hydrolysis to form the final amide product. The Beckmann rearrangement has applications in synthesizing drugs like paracetamol and polymers like nylon.

1. Beckmann Rearrangement
Persented by
Dinesh yadav
2017PCY5358 1
Submitted to:-
Dr. Ragini Gupta
Prof.&HOD
Dept. of Chemistry

2. Beckmann rearrangement
• The acid-catalysed conversion of ketoximes to amides is
known as the Beckmann rearrangement
• The Beckmann rearrangement, named after the German
chemist Ernst Otto Beckmann (1853–1923)
• This rearrangement is occurs in both cyclic and acyclic
compounds .
• Aldoximes are less reactive.
• Cyclic oximes yield lactams and acyclic oximes yield amides
2J. Am. Chem. Soc., 1924, 46 (6), pp 1477–1483 DOI: 10.1021/ja01671a018

3. Beckmann rearrangement
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Reagents:-
Conc.H2SO4, HCl, PCl5, PCl3, SOCl2, ZnO, SiO2, PPA
(Poly phosphoric acid) etc., are commonly employed in
Beckmann rearrangement.
Oxime Amide
J. Am. Chem. Soc., 1924, 46 (6), pp 1477–1483 DOI: 10.1021/ja01671a018

4. Reaction mechanism
The first step in the process is formation of an oxime from the
aldehyde or ketone,
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5. Reaction mechanism
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This rearrangement take place an alkyl migration with expulsion of
the hydroxyl group to form a nitrilium ion followed by hydrolysis.

6. Migratory aptitude
• The relative migratory aptitudes of different groups in Beckmann
rearrangement is illustrated below.
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7. Applications in drug synthesis:-
• An alternative industrial synthesis method for Paracetamol.
It is involves direct acylation of phenol with acetic anhydride
catalyzed by HF, conversion of the ketone to a ketoxime
with hydroxylamine, followed by the acid-catalyzed Beckmann
rearrangement to give the amide
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Paracetamol

8. Applications in drug synthesis:-
• The Beckmann rearrangement is also used in the
synthesis of
1. DHEA
2. Benazepril
3. Etazepine etc.
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9. Applications in polymer synthesis:-
• Beckmann rearrangement can be rendered catalytic using cyanuric
chloride and zinc chloride as a co-catalyst. For
example, cyclododecanone can be converted to the
corresponding lactam, the monomer used in the production
of Nylon 12
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10. Applications in polymer synthesis:-
• The Beckmann rearrangement is also used in
the synthesis of Nylon 6
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11. THANK YOU.
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