Formation of 3,6-di-tert-butyl-2-hydroxyphenoxyl radicals upon the inhibition of polymerization of methyl methacrylate by the system containing 3,6-di-tert-butylpryocatechol and 3,6-di-tert-butyl-1,2-benzoquinone

Conclusions 3,6-Di-tert-butyl-2-hydroxyphenoxyl radicals (QH^.) were detected by EPR spectroscopy in a mixture of 3,6-di-tert-butylpyrocatechol (QH₂) and 3,6-di-tert-butyl-1,2-benzoquinone (Q) in the polymerization of methyl methacrylate. The rate constant for the reaction QH₂ + Q 2QH^. and the rate contants for the forward and back reactions were determined at 60°C.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1188–1190, May, 1989.The authors express their gratitute to Ya. S. Lebedev for a discussion of this work.     

1H NMR Study of Quaternization of 2,4-Di-tert-butyl-6-dimethylaminomethylphenol

The possibility was revealed for exhaustive protonation of 2,4-di-tert-butyl-6-dimethylaminomethylphenol with participation of lone electron pairs on both nitrogen and oxygen atoms. The reaction of the title compound with alkyl halides includes concurrent and consecutive processes leading to formation of the corresponding hydrohalides and quaternization products. The latter undergo spontaneous oxidation with atmospheric oxygen to give quaternary 6,8-di-tert-butyl-3-methyl-2H-3,4-dihydro-1,3-benzoxazine derivatives which were detected by ¹H NMR spectroscopy.     

Heterocycles Based on Sterically Hindered Phenols and their Derivatives. (Review)

Published data on the synthesis of heterocyclic compounds (derivatives of dibenzofuran, phenoxazine, benzodioxolane, etc.) based on sterically hindered 6-substituted 2,4-di-tert-butylphenols, 6-hydroxy-2,4- and 6-hydroxy-2,5-di-tert-butylphenols, and their redox-conjugated ortho-benzoquinones are reviewed.     

Opening of the three-membered ring in 4,6-di-tert-butylspiro[2,5]octa-3,6-dien-5-one under the action of magnesium halides

Conclusions The three-membered ring in 4,6-di-tert-butylspiro[2,5]octa-3,6-dien-5-one opens under the action of magnesium halides with the formation of 4-(-haloethyl)-2,6-di-tert-butylphenols.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 930–932, April, 1967.     

Reaction of 3,6-di-tert-butyl-o-benzoquinone with acids

Conclusions In the reaction of 3,6-di-tert-butyl-o-benzoquinone with acids in different media, the protonated form of the quinone can exhibit the properties of an oxidizing agent or an electrophile, depending on the nature of the acid and solvent.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 9, pp. 2110–2113, September, 1981.     

Rules for antioxidant action of 3,6-di-tert-butylpyrocatechol

Russian Chemical Bulletin -     

Synthesis of heterocyclic derivatives of 3,6-di-tert-butyl-o-benzoquinone by catalytic dehydrocondensation with ethylene glycol, glycerol, and diethanolamine

The dehydrocondensation of 3,6-di-tert-butyl-o-benzoquinone with ethylene glycol, glycerol, its chlorhydrin, and with diethanolamine, catalyzed by MnO₂–NaOH, has been carried out in an alcohol-DMF medium with the formation of 7,10-di-tert-butyl-2,5-dioxabicyclo[4.4.0]deca-1,6-diene-8.9-dione, its 4-hydroxymethyl and 4-chloromethyl derivatives, and 7,10-di-tert-butyl-5-(-hydroxyethyl)-2-oxa-5-azabicyclo[4.4.0]deca-1,6-diene-8,9-dione.N. M. Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Moscow 117977, Russia e-mail: chembio@chph.ras.ru, chembio@glasnet.ru. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1057–1065, August, 2000.     

Solid-phase bromination of hindered phenols

The solid-Phase bromination of a series oftert-butyl-substituted phenols withN-bromosuccinimide and dioxane dibromide afforded halogenated cyclohexadienones, quinobromides. Under the extrusion conditions, the latter underwent further transformations, mainly, debromination. A new reaction, dioxane dibromide catalyzed anhydroheterocyclization of 2,2-dihydroxy-3,3,5,5-tetra-tert-butyldiphenyl to 2,4,6,8-tetra-tert-butyldibenzofuran, was discovered and the mechanism of this reaction was proposed.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 1310–1312, May, 1996.     

Hydroxylation of substituted diatomic phenols and their derivatives

Oxidation of 3,6-di-tert-butylpyrocatechol in protic media is accompanied by the formation of 3,6-di-tert-butyl-2-hydroxy-para-benzoquinone. Hydroxylation of the 3,5-isomer results in dealkylation and isomerization with the formation of 6-tert-butyl-2-hydroxy-para-benzoquinone and the quinone mentioned above, respectively. Their ratio depends on the nature of the solvent. Analogous processes accompany redox transformations of 2,6-di-tert-butylhydroquinone, 2,6-diphenyl-para-benzoquinone, and 2,4,6-tri-tert-butylphenol adsorbed on silica gel. Derivatives of 3,5-substituted pyrocatechols formed under conditions of heterophase oxidation in air are capable of transformations to form nitrogen-containing compounds. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2007–2010, October, 1998.