Oxidation of alkoxyphenols. Part XIV. Thermal rearrangements of some aryloxycyclohexadienones

Abstract

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.

Oxidation of alkoxyphenols. Part 26. The trimer of a 2,2′-diphenoquinone (1,1′-bicyclohexa-3,5-dienylidene-2,2′-dione)

“…As it appeared from these and earlier observations that the blue material, now identified as the diphenoquinone (4), may in some way undergo a redistribution reaction to the dioxepin (2), an experiment was designed that would provide unequivocal evidence for or against this Accordingly, the deuterium labelled dioxepin (7) was prepared as shown in Scheme 3. This was reduced to the diol (8).…”

“…Preparation of 5-Deilteriomethoxy-2', 10'-dimethoxy-3',4,9'tri-t-butyZspiro(cyclohexa-3,5-diene- (7).-A solution of 5,5'-dimethoxy-4,4'-di-tbutylbiphenyl-2,2'-diol (6) (0.1 g) in hexane (200 ml) was vigorously shaken for 15 s with a solution of potassium ferricyanide (1 g) and sodium hydroxide (0.5 g) in water (15 ml). Half of a solution of 4-deuteriomethoxy-3-t-butylphenol (0.05 g) in hexane (50 ml) was then added and stirred gently into the upper layer.…”