Kinetics and mechanisms of the Bamberger rearrangement. Part 3. Rearrangement of phenylhydroxylamines to p-aminophenols in aqueous sulphuric acid solutions

Takaaki Sone, Yuuji Tokuda, Toshimi Sakai, Seiji Shinkai, Osamu Manabe

研究成果: Contribution to journalArticle査読

47 被引用数 (Scopus)

抄録

The rates of Bamberger-type rearrangement of phenylhydroxylamine (1a) and its derivatives (1b-d) to the corresponding p-aminophenols were determined in sulphuric acid solution. Plots of the pseudo-first-order rate constants against pH (or H0) indicate that the active species at [H2SO4] < 1.00N (pH region) is the O-protonated arylhydroxylamine (ArNHO+H2) which exists in equilibrium with the N-protonated species (ArN+H2OH), while the diprotonated species (ArN+H2O+H2) contributes significantly to the observed reaction rate at [H2SO4] > 1.00N (H0 region). The slope of Hammett plots (ρ) which was obtained by plotting kobs at [H2SO4] 1.00N against the Hammett σ values was -3.19. It was also established that the ΔS‡ values for the four substrates are all positive. These results suggest that the Bamberger rearrangement occurs by an SN1 mechanism and that the elimination of water from ArNHO+H2 is rate determining.

本文言語英語
ページ(範囲)298-302
ページ数5
ジャーナルJournal of the Chemical Society, Perkin Transactions 2
2
DOI
出版ステータス出版済み - 1981
外部発表はい

All Science Journal Classification (ASJC) codes

  • Chemistry(all)

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