Chemistry with wiley

Simplified knowledge

Spread the love

Beckmann Rearrangement Reaction mechanism with an application

Rearrangement:- Rearrangement reaction involve a change in the carbon skeleton or migration of loops in the molecule. These are organic reactions in which an atom, ion, group of atoms or chemical unit migrates from one carbon atom to another carbon atom in the same or different molecule resulting in a structural isomer of the original molecule. The reaction often includes the breaking and/or making of carbon-carbon sigma bonds.

This rearrangement occurs due to the electron-deficient nitrogen atom.

Principle of Beckmann rearrangement

The acid-catalyzed conversion of keto oxime into N- substituted amide is known as Beckmann Rearrangement.

General Reaction

Beckmann Rearrangement

Beckmann rearrangement is highly stereospecific. Intramolecular and anti-migration may be justified with a stereochemistry study. The group which is trans to – OH group migrates hence stereochemical different reactants give a stereochemically different product.

Mechanism of Beckmann Rearrangement

Step I:-

Formation of electron-deficient Nitrogen by protonation

Oxime gets protonated in presence of conc. H2SO4 then eliminate water molecule to give positively charged nitrogen species.

The Beckmann rearrangement is often catalyzed by acid, however, other reagents are also reported that promote the rearrangement. These include tosyl chloride, thionyl chloride, phosphorus pentachloride, phosporous pentoxide, TEA, Zinc chloride, etc.

Unstable Species in Beckmann Rearrangement
unstable species

Step II :-

Migration of alkyl or aryl group.

Alkyl or aryl group which is trans to – OH group migrates to electron-deficient Nitrogen with the formation of Carbonium ion

Carbonium ion in Beckmann Rearrangement

Step III:-

Nucleophilic attack & Deprotonation.

Water molecule attacks as a nucleophile to carbocation followed by deprotonation. Protonated compound eliminates proton, giving rise to enol form which changes to keto form which is N substituted amide.

N-Substituted amide
N-Substituted amide

The migrating group never detaches itself from the substrate. Thus migration and loss of leaving functionality occur in a synchronous manner.

The rearrangement pattern of the Beckmann reaction depends on many parameters for example structure of migrating
groups. The migrating aptitude does not depend on the nature of the group (as in another rearrangement like pinacol pinacolone) but on its stereochemical arrangement in the oxime. Generally, the group anti-orientation with respect to the leaving group in the oxime molecule migrates. Intramolecular rearrangement always proceeds through bridged ion.

Beckmann rearrangement is highly stereospecific. Intramolecular and anti-migration may be justified with a stereochemistry study. When Beckmann rearrangement is carried out with a chiral migrating group then it is found that retention of configuration occurs during the rearrangement.

When a mixture of oximes with a tertiary center next to oxime is subjected to a Beckmann rearrangement reaction, cross-over products are obtained showing fragmentation.

The yield of this reaction increases at elevated temperatures and the addition of cocatalyst N-methyl-imidazolium Hydrosulfate.

Cyclic oximes and haloimines yield lactams.

Application of Beckmann Rearrangement :

  1. Preparation of ɛ-caprolactam- B R is used in the preparation of ɛ-caprolactam which is an important raw material for Nylon -6.


2. Preparation of isoquinoline

B R is also used in the preparation of isoquinoline. It is an important chemical used in the pharma and specialty chemical industry.


3. Pharmaceutical Sector-

It is used in the synthesis of paracetamol by converting a ketone to a ketoxime with the help of hydroxylamine

The reaction is also helpful in the synthesis of various steroids and drugs.

4. Other uses

In the production of chloro bicyclic lactams.

Hofmann Rearrangement | What Is Hofmann Rearrangement Reaction| Hofmann Reaction kya hai?

The conversion of amide to an amine with one carbon atom less by the action of alkaline hypohalite (NaOX or KOX) or bromine in alkali is known as Hofmann Rearrangement Reaction or Hofmann bromamide reaction. Read more

What is Pinacol – Pinacolone Rearrangement | Pinacol – Pinacolone Rearrangement kya hai?

The reactions involving the migration of an atom ( like H) or group (like methyl, ethyl, etc) from one atom to another (i.e. change in the bonding sequence within a molecule) are known as molecular rearrangements or rearrangement reactions. Read more..


What is Beckmann rearrangement give one example.

The acid-catalyzed conversion of keto oxime into N- substituted amide is known as Beckmann Rearrangement.

Which group migrates in Beckmann rearrangement?

Alkyl or aryl group which is anti to oxime.

What is the application of Beckmann rearrangement?

Mainly in the preparation of caprolactum

What is the product in Beckmann rearrangement?

N-substituted amide

What is oxime?

An oxime is a chemical compound belonging to the imines family, having the general formula as RR’C=NOH, where R is nothing but an organic side-chain and R’ may be hydrogen, forming an aldoxime, or another organic group, forming a ketoxime.

Spread the love

41 thoughts on “Beckmann Rearrangement | Beckmann Rearrangement Mechanism | Beckmann rearrangement kya hai?

  1. Hello are using WordPress for your site platform? I’m new to the blog world but I’m trying to get started and set up my own. Do you require any coding knowledge to make your own blog? Any help would be greatly appreciated!

  2. Thanks for your publiction. Another factor is that being photographer involves not only difficulties in catching award-winning photographs but also hardships in getting the best camera suited to your requirements and most especially situations in maintaining the standard of your camera. This really is very real and apparent for those photography enthusiasts that are into capturing the nature’s captivating scenes – the mountains, the actual forests, the particular wild or even the seas. Going to these amazing places definitely requires a digital camera that can live up to the wild’s hard landscapes.

  3. Thanks a lot for sharing this with all of us you actually know what you’re speaking about! Bookmarked. Kindly additionally seek advice from my website =). We may have a link alternate arrangement between us!

  4. I抦 not that much of a internet reader to be honest but your sites really nice, keep it up! I’ll go ahead and bookmark your website to come back in the future. Cheers

  5. After research a few of the weblog posts on your web site now, and I actually like your way of blogging. I bookmarked it to my bookmark web site record and might be checking back soon. Pls take a look at my site as well and let me know what you think.

  6. I enjoy you because of your entire effort on this blog. My mother loves going through investigations and it’s easy to see why. My spouse and i know all relating to the lively way you produce very useful thoughts on this web site and therefore boost response from other people about this point while our own girl is always understanding so much. Enjoy the rest of the new year. You are always conducting a really good job.

  7. Thanks , I have recently been looking for info approximately this topic for a long time and yours is the best I have came upon so far. But, what in regards to the bottom line? Are you positive concerning the supply?

  8. I was wondering if you ever considered changing the structure of your blog? Its very well written; I love what youve got to say. But maybe you could a little more in the way of content so people could connect with it better. Youve got an awful lot of text for only having 1 or 2 images. Maybe you could space it out better?

  9. After study few of the articles on your web site today, and I really like your way of blogging. I tag it to my bookmark internet site list and will be checking back soon. Pls visit my internet site also and let me know your thought.

  10. Thank you a bunch for sharing this with all of us you actually recognize what you’re speaking approximately! Bookmarked. Please additionally seek advice from my website =). We could have a link change contract between us!

  11. I actually wanted to make a brief word to be able to appreciate you for the amazing instructions you are showing on this website. My incredibly long internet look up has now been compensated with brilliant know-how to share with my family and friends. I would mention that we readers are unequivocally lucky to exist in a really good website with very many perfect professionals with beneficial things. I feel somewhat happy to have used the webpage and look forward to many more entertaining times reading here. Thank you once more for all the details.

  12. Wow! This could be one particular of the most helpful blogs We’ve ever arrive across on this subject. Basically Excellent. I’m also a specialist in this topic so I can understand your hard work.

  13. Hello there, I believe your site might be having browser compatibility issues.
    When I take a look at your website in Safari, it looks fine however, when opening in Internet Explorer, it has some overlapping issues.
    I merely wanted to provide you with a quick heads up!
    Apart from that, wonderful blog!

  14. Does it give any better than this!?! As a full-time writer myself is always good to read such a well written and well thought out content.

  15. Hey, you used to write fantastic, but the last several posts have been kinda boring… I miss your super writings. Past few posts are just a bit out of track! come on!

  16. Thanks for all of your work on this blog. Gloria really likes engaging in internet research and it’s really simple to grasp why. My partner and i learn all regarding the lively way you deliver precious information on the website and therefore invigorate participation from visitors on that issue and our daughter is now discovering a lot of things. Take advantage of the remaining portion of the new year. You’re the one performing a first class job.

  17. My brother recommended I might like this blog. He was entirely right. This publish truly made my day. You can not believe just how so much time I had spent for this info! Thanks!

Leave a Reply

Your email address will not be published. Required fields are marked *