Pfitzinger reaction
The Pfitzinger reaction (also known as the Pfitzinger-Borsche reaction) is the chemical reaction of isatin with base and a carbonyl compound to yield substituted quinoline-4-carboxylic acids.[1][2]
![](../I/m/Pfitzinger_Reaction_Scheme.png)
The Pfitzinger reaction
Pfitzinger reaction | |||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Named after | Wilhelm Pfitzinger | ||||||||||||
Reaction type | ring-condensation | ||||||||||||
Reaction | |||||||||||||
| |||||||||||||
Conditions | |||||||||||||
Typical solvents | protic | ||||||||||||
Identifiers | |||||||||||||
RSC ontology ID | RXNO:0000109 | ||||||||||||
Reaction mechanism
![](../I/m/Pfitzinger_Reaction_Mechanism.png)
The mechanism of the Pfitzinger reaction
The reaction of isatin with a base such as potassium hydroxide hydrolyses the amide bond to give the keto-acid 2. This intermediate can be isolated, but is typically not. A ketone (or aldehyde) will react with the aniline to give the imine (3) and the enamine (4). The enamine will cyclize and dehydrate to give the desired quiniline (5).
Variations
Halberkann variant
![](../I/m/Pfitzinger_Halberkann_Modification_Scheme.png)
The Halberkann variant of the Pfitzinger reaction
Reaction of N-acyl isatins with base gives 2-hydroxy-quinoline-4-carboxylic acids.[6]
gollark: The average person really does not want to do anything remotely complicated with a computer, which is problematic, and it doesn't really *help* that a bunch of stuff (down to the balance of upload/download speeds available on home network connections) on the internet is set up now to encourage using big walled gardens and discourage running your own stuff.
gollark: Well, you can't easily, which is the problem.
gollark: Because it's run by a bunch of individuals or smaller groups and can be networked together.
gollark: Which is why I like self-hostable/federated stuff.
gollark: It's not hard technologically. It's hard to make people move.
See also
References
- Pfitzinger, W. (1886). "Chinolinderivate aus Isatinsäure". J. Prakt. Chem. (in German). 33 (1): 100. doi:10.1002/prac.18850330110.
- Pfitzinger, W. (1888). "Chinolinderivate aus Isatinsäure". J. Prakt. Chem. (in German). 38 (1): 582–584. doi:10.1002/prac.18880380138.
- Manske, R. H. (1942). "The Chemistry of Quinolines". Chem. Rev. 30 (1): 113–144. doi:10.1021/cr60095a006.
- Bergstrom, F. W. (1944). "Heterocyclic Nitrogen Compounds. Part IIA. Hexacyclic Compounds: Pyridine, Quinoline, and Isoquinoline". Chem. Rev. 35 (2): 77–277. doi:10.1021/cr60111a001.
- Shvekhgeimer, M. G.-A. (2004). "The Pfitzinger Reaction". Chem. Heterocycl. Compd. 40 (3): 257–294. doi:10.1023/B:COHC.0000028623.41308.e5.)
- Halberkann, J. (1921). "Abkömmlinge der Chininsäure". Chem. Ber. (in German). 54 (11): 3090–3107. doi:10.1002/cber.19210541118.
This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.