Bamberger rearrangement
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The Bamberger rearrangement is the chemical reaction of N-phenylhydroxylamines with strong aqueous acid, which will rearrange to give 4-aminophenols.[#endnote_Bamberger1894][#endnote_OS1955]
N-Phenylhydroxylamines are typically synthesized from nitrobenzenes by reduction using rhodium[#endnote_Oxley1989] or zinc[#endnote_Kamm1925].
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.[#endnote_Sone1981][#endnote_Kohnstam1984]
References
- ↑ Bamberger, E. Ber. 1894, 27, 1347 & 1548.
- ↑ Harman, R. E. Organic Syntheses, Coll. Vol. 4, p.148 (1963); Vol. 35, p.22 (1955). ([Article])
- ↑ Oxley, P. W.; Adger, B. M.; Sasse, M. J.; Forth, M. A. Organic Syntheses, Coll. Vol. 8, p.16 (1993); Vol. 67, p.187 (1989). ([Article])
- ↑ Kamm, O. Organic Syntheses, Coll. Vol. 1, p.445 (1941); Vol. 4, p.57 (1925). ([Article])
- ↑ Sone, T.; Hamamoto, K.; Seiji, Y.; Shinkai, S.; Manabe, O. J. Chem. Soc. Perkins Trans. II 1981, 1596-1598.
- ↑ Kohnstam, G. et al. J. Chem. Soc. Perkins Trans. II 1984, 423.
See also
- Hofmann-Martius rearrangement
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