- Liquid-Phase Oxidation of Inorganic Sulfides in Aqueous Media in the Presence of a Homogeneous Catalyst Based on 3,3′,5,5′-Tetra-tert-Butyl-4,4′-Stilbenequinone
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The rates and factors influencing the rates of liquid-phase oxidation of inorganic sulfides by oxygen in aqueous media in the presence of a homogeneous catalyst based on 3,3′,5,5′-tetra-tert-butyl-4,4′-stilbenequinone dissolved in the kerosene fraction ha
- Hoang,Akhmadullin,Akhmadullina, F. Yu.,Zakirov,Akhmadullina
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- Isolation and identification of 3,3',5,5'-tetrabis(tert-butyl)stilbenequinone from polyethylene closures containing titanium dioxide and butylated hydroxytoluene
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A yellow compound was isolated from commercially available, discolored, polyethylene ophthalmic closures containing titanium dioxide and butylated hydroxytoluene (I). This compound was present at 7.46 ppm (w/w). It was identified by UV, IR, and mass spectra as 3,3',5,5'-tetrabis (tert-butyl)stilbenequinone (II), a dimer of I. Further structural confirmation was obtained by NMR. Formation of II is catalyzed by titanium dioxide.
- Jagnandan,Daun,Ambrosio,Gilbert
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- New data on the reaction of diethyl hydrogen phosphite with 3,5-di-tert-butyl-4-hydroxybenzaldehyde
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3,3′,5,5′-Tetra-tert-butylstilbene quinone and 1,2-bis(3,5-di-tert-butyl-4-hydroxyphenyl)-1,2-bis-(diethoxyphosphinoyl)-ethane were isolated from a mixture of products of the reaction of equivalent amounts of diethyl hydrogen phosphite and 3,5-di-tert-butyl-4-hydroxybenzaldehyde. A scheme of chemical transformations in this reaction system was offered.
- Ismagilov,Moskva,Mosunova,Romakhin
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- TEMPO-Mediated Cross-Dehydrogenative Coupling of Indoles and Imidazo[1,2- a]pyridines with Fluorinated Alcohols
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A simple and highly efficient metal-free method has been developed for hydroxyfluoroalkylation of indoles and imidazo[1,2-a]pyridines via TEMPO-mediated C(sp3)-H and C(sp2)-H bond cross-dehydrogenative coupling of fluorinated alcohols and indoles. The protocol showed broad substrate scope, afforded good yields of hydroxyfluoroalkylated products, and was amenable for scale-up. Mechanistic investigation indicated involvement of the radical pathway.
- Nipate, Dhananjay S.,Jaspal, Sonam,Shinde, Vikki N.,Rangan, Krishnan,Kumar, Anil
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supporting information
p. 1373 - 1377
(2021/02/20)
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- Synthesis of 3,3′,5,5′-Tetra-tert-butyl-4,4′-stilbenequinone and Its Catalytic Activity in the Liquid-Phase Oxidation of Inorganic Sulfides
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The oxidation of 2,6-di-tert-butyl-4-methylphenol with hydrogen peroxide in the presence of potassium iodide gave 3,3′,5,5′-tetra-tert-butyl-4,4′-stilbenequinone which catalyzed liquid-phase oxidation of sodium sulfide with oxygen more efficiently than di
- Hoang,Akhmadullin,Akhmadullina, F. Yu.,Zakirov,Akhmadullina,Gazizov
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p. 1008 - 1013
(2018/09/12)
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- Investigation of 3,3′,5,5′-tetra-tert-butyl-4,4′-stilbenequinone-based catalyst in the reaction of liquid-phase oxidation of inorganic sulfides
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In this paper, the intermediate and final reaction products of catalytic oxidation of inorganic sulfides in the presence of oxygen dissolved in the kerosene fraction and 3,3′,5,5′-tetra-tert-butyl-4,4′-stilbenequinone were investigated. The thiosulfate and sulfate are major products of the oxidation of sodium sulfide under these conditions. The intermediate and final products in the catalytic oxidation of sulfide sulfur do not affect the rate of its oxidation. The yield of catalytic oxidation products depends on the nature of the sulfide and on the pH of the solution. The catalytic cycle for sulfide oxidation in the presence of 3,3′,5,5′-tetra-tert-butyl-4,4′-stilbenequinone is shown. The role of 3,3′,5,5′-tetra-tert-butyl-4,4′-stilbenequinone is to create a new and a more effective way of electron transfer from the reducing agent (sulfide) to the oxidant (oxygen).
- Hoang, Hien Y.,Akhmadullin, Renat Maratovich,Akhmadullina, Farida Yunusovna,Zakirov, Rustem Kayumovich,Bui, Dinh Nhi,Akhmadullina, Alfiia Garipova,Gazizov, Almir Sabirovich
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p. 130 - 139
(2017/11/16)
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- Reaction of esters of PIII acids with 2,6-di-tert-butyl-4-chloromethylidenecyclohexa-2,5-dienone
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A reaction of PIII acid esters with 2,6-di-tert-butyl-4-chloromethylidenecyclohexa-2,5-dienone leads to the formation of phosphorylated phosphorus ylides, 3,3’,5,5’-tetra-tert-butylstilbenequinone, and diphosphorylated sterically hindered phenols. The schemes for the formation of these products through the primary key intermediates of betaine and phosphorus ylide structures were suggested.
- Gazizov,Ismagilov,Shamsutdinova,Tarakanova,Karimova
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p. 2943 - 2947
(2017/06/05)
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- Metal-free C-H amination for indole synthesis
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An effective metal-free C-H amination of N-Ts-2-alkenylanilines by using DDQ as an oxidant has been developed to afford a diverse range of substituted indoles. This protocol is operationally simple and robust, obviates the need of expensive transition-metal catalysts, and offers a broad substrate scope. A mechanism involving a radical cation generated by SET and a migratorial process via a phenonium ion intermediate is proposed.
- Jang, Young Ho,Youn, So Won
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supporting information
p. 3720 - 3723
(2014/08/05)
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- Study of the reaction of 4-chloromethylene-2,6-di-tert-butylcyclohexa-2,5- dien-1-one with the P(III) acids esters
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The main stable products of the reactions 4-chloromethylene-2,6-di-tert- butylcyclohexa-2,5-dien-1- one with triethyl phosphite and ethyl diphenylphosphinite are the phosphorylated phosphorus ylides, 3,3′,5,5′-tetra-tert-butylstilbenequinone, and biphosph
- Gazizov,Ismagilov,Shamsutdinova,Karimova,Sinyashin
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experimental part
p. 212 - 216
(2012/07/02)
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- Coupling and fast decarboxylation of aryloxyl radicals of 4-hydroxycinnamic acids with formation of stable p-quinomethanes
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The reaction at room temperature of 3,5-di-tert-butyl- and 3,5-di-methoxy-4-hydroxycinnamic acids 1 and 2 with the dpph. radical in acetone or other non-hydroxylic polar solvents yields interesting dimeric p-quinomethanes 10-16 characterized by
- Daquino, Carmelo,Foti, Mario C.
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p. 1536 - 1547
(2007/10/03)
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- Practical process for the air oxidation of cresols: Part A. Mechanistic investigations
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The catalytic air oxidation of p-cresol and 2,6-di-tert-butyl-4- methylphenol to the corresponding benzaldehydes was investigated to determine the mechanism at work in these oxidation reactions. A number of intermediates and byproducts, mainly in the form of dimers, were observed during the course of the reactions, and their structures were elucidated by spectroscopic and chromatographic methods. The existence of these compounds in the reaction mixtures, and their proposed methods of formation, provided further insight into the mechanism involved in these oxidations.
- Barton, Benita,Logie, Catherine G.,Schoonees, Barbara M.,Zeelie, Bernard
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- Use of 1-halo derivatives of the 2,2,6,6-tetramethylpiperidine series as oxidants and halogenating agents
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1-Halo derivatives of the 2,2,6,6-tetramethylpiperidine series oxidize sterically hindered phenols to form dimers and p-quinones.
- Kashparova,Kagan,Zhukova,Ivakhnenko
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p. 964 - 967
(2007/10/03)
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- Process research and development of a dihydropyrimidine dehydrogenase inactivator: Large-scale preparation of eniluracil using a sonogashira coupling
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Eniluracil (5-ethynyluracil) is a potent inactivator of the enzyme dihydropyrimidine dehydrogenase, which is the rate-limiting enzyme in the metabolism of 5-fluorouracil, a widely used anti-cancer drug. The process research and development of a three-stag
- Cooke, Jason W. B.,Bright, Robert,Coleman, Mark J.,Jenkins, Kevin P.
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p. 383 - 386
(2013/09/07)
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- Oxidative Dehydrogenation of Sterically Hindered para-Substituted Phenols with 3,3′,5,5′-Tetra-tert-butyl-4,4′-diphenoquinone
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The reactivity of 4-methyl-, 4-mercapto-, and 4-methoxymethyl-2,6-di-tert-butylphenols in oxidative dehydrogenation with 3,3′,5,5′-tetra-tert-butyl-4,4′-diphenoquinone was studied, and the structure of products was determined.
- Mukmeneva,Bukharov,Kadyrova,Zharkova,Gorshunova,Fazlieva
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p. 1486 - 1489
(2007/10/03)
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- Stabilizer of isoprene rubber and thermoplastic compositions on its base
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The stabilizing efficiency was studied of the products of oxidative dehydration of 4-methyl-2,6-di-tert-butylphenol with 3,3′,5,5′-tetra-tert-butyl-4,4′-diphenoquinone in SKI-3 synthetic isoprene rubber and a thermoplastic composition based on SKI-3 and polypropylene.
- Fazlieva,Mukmeneva,Bukharov,Vol'fson
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p. 1252 - 1253
(2007/10/03)
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- Antioxidant Synergism Between Butylated Hydroxyanisole and Butylated Hydroxytoluene
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Decay of the 2,6-di-tert-butyl-4-methylphenoxy radical in the presence of butylated hydroxyanisole (BHA) was investigated in 1,2-dimethoxyethane with or without triethylamine.BHT-radical was conveniently generated by dissociation of its unstable dimer in solution.The products were BHT, 3,3'-di-tert-butyl-5,5'-dimethoxy-2,2'-dihydroxybiphenyl (BHA-dimer), 2,6-di-tert-butyl-p-quinone methide (QM), 1,2-bis(3,5-di-tert-butyl-4-hydroxyphenyl)ethane, and 3,3',5,5'-tetra-tert-butyl-4,4'-stilbenequinone.The reaction without added triethylamine gave larger quantities of the last two products and BHA (recovery), whereas the reaction with it provided larger quantities of the first two products.The marked difference in the product distribution can be accounted for by a series of reactions including reversible dehydrogenation of BHA with BHT-radical, which generates 2-tert-butyl-4-methoxyphenoxy radical (BHA-radical) and BHT, reversible dimerization of BHA-radical, which affords an intermediary bis(cyclohexadienone), and spontaneous and base-catalysed prototropic rearrangement of the intermediate into BHA-dimer.Products of coupling between BHT-radical and BHA-radical were not obtained.BHA was found to undergo facile acid-catalyzed addition to QM, providing two isomeric bis(hydroxyphenyl)methanes.The results help to elucidate the mechanism of antioxidant synergism between BHA and BHT and may suggest that the synergism can be affected by base or acid. - Key words: Antioxidant synergism; butylated hydroxyanisole; butylated hydroxytoluene; effect of acid; effect of base; fate of phenoxy radicals involved.
- Omura, Kanji
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p. 1565 - 1570
(2007/10/03)
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- Acetyl chloride - 3,5-di(tert-butyl)-4-hydroxy-N,N-dimethylbenzylamine salt in the benzylation of organic and inorganic sulfur-containing compounds
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The reactions of the quaternary acylammonium salt formed on treatment of 3,5-di-tert-butyl-4-hydroxy-N,N-dimethylbenzylamine with acetyl chloride, with various organic and inorganic sulfur-containing compounds were studied.The possibility of using this salt for the introduction of a sterically hindered phenol moiety in various sulfur-containing compounds was shown. - Key words: sterically hindered phenols, quaternary ammonium salts, benzylation, thiourea.
- Gorbunov, D. B.,Voznesenskii, V. N.,Ershov, V. V.,Nikiforov, G. A.
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- Chemical evidence for peroxy radicals intermediacy in copper(II) reaction with hydroperoxides
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Two unprecedented decompositions of tertiary hydroperoxides by Cu(II) in CH3CN have been encountered : deoxygenation of 4- hydroperoxy cyclohexa 2,5- dienones 1 and 2 brings chemical support to the existence of intermediate peroxy radicals R-OO· 1′ and 2′.
- Maumy, Michel,Capdevielle, Patrice
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p. 7455 - 7462
(2007/10/02)
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- Reinvestigation on the Reaction of 2,6-Di-tert-butylbenzoquinone Methide and 2,6-Di-tert-butylphenol
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The reaction of quinone methide 1 and phenol 2 in equimolar amounts was investigated in pentane at 30 deg C.Products were isolated by means of column chromatography on SiO2.There was a marked difference in product distribution between the reactions in the presence and absence of added Et3N.Dienones 3 and 10 were obtained only from the former reaction, while formation of 1,2-bis(4-hydroxyphenyl)ethane 18 and 4,4'-dihydroxybiphenyl 20 was overwhelming in the latter reaction.Other products from both reactions were relatively small quantities of 4,4'-stilbenequinone 17, 4,4'-diphenoquinone 21, and bis(4-hydroxyphenyl)methane 24, but dienone 4 was not obtained.Compounds 20 and 24 obtained from the latter reaction were formed by isomerization of dienones 19 and 23, respectively, during chromatography.The reaction is initiated by dimerization of 1 to generate biradical 11.Subsequent processes involving hydrogenation-dehydrogenation, coupling-dissociation, and dienone-phenol rearrangement account for the formation or the lack of formation of the products.The difference in product distribution is ascribed to capability of Et3N to catalyze the isomerization.Quinone methide 1 also adds to 2 to give 23.The decay of 1 in the presence of both 2 and phenol 6 gave dienone 8 additionally.The formation of 24 and 4 was facilitated by conducting the reaction of 1 and 2 in DMSO.Dehydrogenation of 10 and 3 with PbO2 afforded spirodienones 27 and 28, respectively.Compounds 27 and 28 were unstable, and their decay in solution was investigated in the presence or absence of added 2.The results show that the decay is initiated by homolytic scission of the C-C bond connecting the dienone rings in the cyclopentane (in 27) and cyclohexane (in 28) rings.Compound 28 is novel in that it bears two kinds of such C-C bonds.Reversibility of the dimerization of 1 is suggested.
- Omura, Kanji
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p. 306 - 312
(2007/10/02)
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- Oxidation by Cobalt(III) Acetate. Part 13. Oxidation of Substituted Phenols with Cobalt(III) Acetate in Acetic Acid
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The oxidation of 2,6-di- and 2,4,6-tri-substituted phenols with cobalt(III) acetate has been investigated in acetic acid under an inert atmosphere; the former gave the corresponding diphenoquinones in excellent yields, and the latter yielded side-chain or nuclear acetoxylated products in moderate to good yields.
- Hirano, Masao,Ishii, Tadamichi,Morimoto, Takashi
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p. 1434 - 1436
(2007/10/02)
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- Oxidation of Phenols with Iodine in Alkaline Methanol
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The use of iodine as an oxidizing agent for phenolic compounds has been explored.The reaction has been conducted in methanol containing such alkali as potassium hydroxide and, depending on the nature of the substituents and on the amount of iodine employed, leads to iodination, oxidation to give a stable phenoxy radical, oxidative dimerization, or benzylic oxidation.In general the reaction proceeds smoothly at room temperature, and under appropriate conditions yields of products are good to excellent.Oxidative dimerization of 2,4- and 2,6-di-tert-butylphenols invol-ves iodination followed by iodine-catalyzed dimerization.The oxidation of 4-methylphenols with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone in methanol has been carried out for comparison.
- Omura, Kanji
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p. 3046 - 3050
(2007/10/02)
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- Oxidation of Bisphenols. II. Some Compounds Related to Galvinoxyl
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The oxidation of a series of 4,4'-alkylidenebis(2,6-di-t-butylphenols) having increasing substitution of the central methylene carbon by alkyl groups is examined.In the monosubstituted compounds the stability of the monophenoxy radical increases with increase in the size of the substituent, while the stability of the galvinoxyl type radical decreases. β-Coupled products are only obtained from the ethylidene bisphenol, a result that can be correlated with e.s.r. hyperfine splitting constants.With increasing mono- or di-substitution bisspiroperoxides become the preferred oxidation products.The e.s.r. spectrum of an ethylenebisgalvinoxyl biradical is described
- Colegate, Steven M.,Hewgill, F. Richmond
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p. 351 - 369
(2007/10/02)
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