Bamberger rearrangement
Chemical reaction
From Wikipedia, the free encyclopedia
The Bamberger rearrangement is the chemical reaction of phenylhydroxylamines with strong aqueous acid, which will rearrange to give 4-aminophenols.[1] It is named for the German chemist Eugen Bamberger (1857–1932).[2][3]
The starting phenylhydroxylamines are typically synthesized by the transfer hydrogenation of nitrobenzenes using rhodium[4] or zinc[5] catalysts.
One application is in the synthesis of fenhexamid.
Reaction mechanism
The mechanism of the Bamberger rearrangement proceeds from the monoprotonation of N-phenylhydroxylamine 1. N-protonation 2 is favored, but unproductive. O-protonation 3 can form the nitrenium ion 4, which can react with nucleophiles (H2O) to form the desired 4-aminophenol 5.[6][7]
See also
- Friedel–Crafts alkylation-like reactions:
- Bamberger triazine synthesis — same inventor