Fischer–Hepp rearrangement
In the following article we are going to delve into the exciting world of Fischer–Hepp rearrangement, exploring its most relevant aspects and its implications in modern society. From its emergence to its effects on an individual and collective level, we will embark on a journey of discovery and reflection that will allow us to better understand Fischer–Hepp rearrangement and its impact on our daily lives. Through in-depth analysis and case studies, we will seek to shed light on the lesser-known aspects of Fischer–Hepp rearrangement and its relevance in the contemporary world. Join us on this journey of knowledge and discovery, where we hope to open perspectives and generate reflections around Fischer–Hepp rearrangement.
| Fischer-Hepp rearrangement | |
|---|---|
| Named after | Otto Fischer Eduard Hepp |
| Reaction type | Rearrangement reaction |
| Identifiers | |
| RSC ontology ID | RXNO:0000095 |
In organic chemistry, the Fischer–Hepp rearrangement is a rearrangement reaction in which an aromatic N-nitroso (−N=O) or secondary nitrosamine (>N−N=O) converts to a carbon nitroso compound:[1][2]
This organic reaction was first described by the German chemist Otto Philipp Fischer (1852–1932) and Eduard Hepp (June 11, 1851 – June 18, 1917) [3] in 1886, and is of importance because para-NO secondary anilines cannot be prepared in a direct reaction.
The rearrangement reaction takes place by reacting the nitrosamine precursor with hydrochloric acid. The chemical yield is generally good under these conditions, but often much poorer if a different acid is used.[4] The exact reaction mechanism is unknown but the chloride counterion is likely not relevant, except in a competing decomposition reaction. There is evidence suggesting an intramolecular reaction, similar to that seen in the Bamberger rearrangement. Nitrosation follows the classic patterns of electrophilic aromatic substitution (for example, a meta nitro group inhibits the reaction), although substitution ortho to the amine is virtually unknown. The final step, in which a proton eliminates from the Wheland intermediate, appears to be rate-limiting, and the rearrangement is also suppressed in excessive (e.g. >10M sulfuric) acid.[5]
See also
References
- ^ Fischer, Otto; Hepp, Eduard (July–December 1886). "Zur Kenntniss der Nitrosamine". Berichte der Deutschen Chemischen Gesellschaft zu Berlin. 19 (2): 2991–2995. doi:10.1002/cber.188601902297. eISSN 1099-0682. hdl:2027/njp.32101044028619. ISSN 0365-9496. S2CID 95280925. Zenodo 1425449. Gallica ark:/12148/bpt6k907075/f473.item.
- ^ M B Smith, J March. March's Advanced Organic Chemistry (Wiley, 2001) (ISBN 0-471-58589-0) / Michael B., Smith (2013). "11.6.2.2 Groups Cleaving from Nitrogen; Reaction 11-29: Migration of the Nitroso Group: The Fischer–Hepp Rearrangement". March's Advanced Organic Chemistry - Reactions, Mechanisms, and Structure (7th ed.). Hoboken, New Jersey: John Wiley & Sons, Inc. p. 639. ISBN 978-0-470-46259-1. LCCN 2012027160.
- ^ Pötsch, Winfried R.; Fischer, Annelore; Müller, Wolfgang (1988–1989). Lexikon bedeutender Chemiker. With the collaboration of Heinz Cassebaum. Thun & Frankfurt: Verlag Harri Deutsch / VEB Bibliographisches Institut Leipzig. pp. 148, 197. ISBN 3-8171-1055-3.
- ^ Smith, Michael B. (2020). March's Organic Chemistry (8th ed.). Wiley. pp. 678–679.
- ^ Williams, D. L. H. (1988). Nitrosation. Cambridge, UK: Cambridge University. pp. 115–125. ISBN 0-521-26796-X.
Sources
- Andraos, John (2000–2012). "Named Things in Chemical Industry" (PDF). Named Things in Chemistry & Physics. Archived (PDF) from the original on 2023-04-07. Retrieved 2024-05-01.