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Bamberger rearrangement

Lianyungang Klinechem Co.,Ltd | Updated: Nov 29, 2018

The Bamberger rearrangement is the chemical reaction of phenylhydroxylamines with strong aqueous acid, which will rearrange to give 4-aminophenols.[1][2][3] It is named for the German chemist Eugen Bamberger (1857–1932).


The starting phenylhydroxylamines are typically synthesized by the transfer hydrogenation of nitrobenzenes using rhodium[4] or zinc[5] catalysts.

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:

·         Hofmann-Martius rearrangement

·         Fries rearrangement

·         Fischer–Hepp rearrangement


1.     Jump up^ Bamberger, E. (1894). "Ueber die Reduction der Nitroverbindungen"Chemische Berichte27 (2): 1347–1350. doi:10.1002/cber.18940270229.

2.     Jump up^ Bamberger, E. (1894). "Ueber das Phenylhydroxylamin"Chemische Berichte27 (2): 1548–1557. doi:10.1002/cber.18940270276.

3.     Jump up^ Harman, R. E. (1955). "Chloro-p-benzoquinone" (PDF)Organic Syntheses35: 22.Collective Volume, 4, p. 148

4.     Jump up^ Oxley, P. W.; Adger, B. M.; Sasse, M. J.; Forth1, M. A. (1989). "N-ACETYL-N-PHENYLHYDROXYLAMINE VIA CATALYTIC TRANSFER HYDROGENATION OF NITROBENZENE USING HYDRAZINE AND RHODIUM ON CARBON". Organic Syntheses. 67: 187. doi:10.15227/orgsyn.067.0187.

5.     Jump up^ Kamm, O. (1925). "β-Phenylhydroxylamine"Organic Syntheses4: 57.Collective Volume, 1, p. 445 (download PDF)

6.     Jump up^ Sone, T.; Hamamoto, K.; Seiji, Y.; Shinkai, S.; Manabe, O. (1981). "Kinetics and Mechanisms of the Bamberger Rearrangement. Part 4. Rearrangement of Sterically Hindered Phenylhydroxylamines to 4-Aminophenols in Aqueous Sulphuric Acid Solution". Journal of the Chemical Society, Perkin Transactions 21981 (2): 1596–1598. doi:10.1039/P29810000298.

7.     Jump up^ Kohnstam, G.; Petch, W. A.; Williams, D. L. H. (1984). "Kinetic Substituent and Isotope Effects in the Acid-Catalysed Rearrangement of N-Phenylhydroxylamines. Are Nitrenium Ions Involved?". Journal of the Chemical Society, Perkin Transactions 21984 (3): 423–427. doi:10.1039/P29840000423.

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