Oxidation of alkoxyphenols. Part XVII. Competitive oxidative demethylation and debromination

Abstract

The action of sodium bismuthate in acetic acid, and of lead tetra-acetate in non-polar solvents, on a series of t-butylphenols with methoxy-and bromo-groups in o-or p-positions has been examined. Quinones, or their precursors, resulting from demethylation rather than debromination, were produced, except in one case, where the bromo-group was ortho to the t-butyl group. Those phenols with an o-methoxy-group gave unstable o-acetoxycyclohexa-2.4-dienone intermediates. The effects of the two oxidants were almost identical. Nedlands, W.A. OXIDATIVE removal of bromine from bromophenols 2-cand demethylation of alkoxyphenols to quinones 6-8 by strong oxidants by way of carbonium ions9 have been observed by many. For a comparative study of these reactions we have prepared and oxidised the phenols Compounds (I) and (11) were prepared by bromination of the corresponding phenols in acetic acid. Although the structure of compound (I) is confirmed by its n.m.r. spectrum, which shows the para-orientation of the

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“…In synthetic and analytical chemistry Bi(V) is being used since long. [1][2][3] The solution chemistry of Bi(V) is not well explored as yet. In recent year some workers [4][5][6][7][8][9][10][11] have studied the redox kinetics of Bi(V) using hydrogen fluoride and perchloric acid mixture.…”

Kinetics and mechanism of oxidation of formic acid by bismuth(V) in aqueous phosphoric acid medium

“…The solution chemistry of bismuth(V) is still not well understood despite the fact that the sodium bismuthate salt -a source [1 -5] of bismuth(V) -has frequently been employed both in synthetic [6,7] and analytical [8] chemistry. The selective oxidation of corticosteriods by the reagent is considered a significant application in chromatographic analysis [9].…”