Bamberger rearrangement

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 [fr].

The mechanism of the Bamberger rearrangement proceeds from the monoprotonation of N-phenylhydroxylamine 1.