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
When gently heated, the p-aryloxycyclohexadienone obtained by oxidation of 5-methoxy-2,4-di-t-butylphenol, rearranges to 2,2'-dihydroxy-6,6'-dimethoxy-3,3',5,5'-tetra-t-butylbiphenyl.Under similar conditions the analogous dienone derived from 4-methoxy-2.5-di-t-butylphenol gives the trimeric 2,4-diaryloxydienone, the dimeric o-aryloxyphenol, and the parent phenol. Evidence is presented in support of a suggested mechanism for this reaction. Electron spin resonance spectra obtained from these and related aryloxydienones are described.
Die beiden stereoisomeren Olefine (I) und (IV) werden mit einem Katalysator aus Palladiumchlorid und Kupferchlorid in Eisessig/Natriumacetat behandelt und die Reaktionsprodukte (IIa), (IIb) und (III) bzw. (Va), (Vb), (VIa) und (VIb) erhalten.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.