Beckmann rearrangement ppt

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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