- Development of a one-stage synthesis of 2,6-di-tert-4-ethylbutylphenol from 2,6-di-tert-butylphenol
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Investigation of the catalyzed reaction of 2,6-di-tert-butylphenol with ethanol, ethylene glycol, oligomeric glycols, and paraldehyde in a strongly basic medium permitted to develop a technologically suitable procedure for manufacture of 2,6-di-tert-4-ethyl-butylphenol, used in the synthesis of Antioxidant-425.
- Krysin,Pokrovskii
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experimental part
p. 1728 - 1733
(2009/02/06)
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- Radical ion probes, 8. Direct and indirect electrochemistry of 5,7-di-tert-butylspiro[2.5]octa-4,7-dien-6-one and derivatives
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Results pertaining to the direct and indirect electrochemistry of 5,7-di-tert-butylspiro[2.5]octa-4,7-dien-6-one (1a), 1-methyl-5,7-di-tert-butylspiro[2.5]octa-4,7-dien-6-one (1b), and 1,1,-dimethyl-5,7-di-tert-butylspiro[2.5]octa-4,7-dien-6-one (1c) are reported. Product analyses reveal that reduction of all these substrates leads to cyclopropane ring-opened products; ring opening occurs with modest selectivity leading to the more substituted (stable) distonic radical anion. The direct electrochemistry of these compounds is characterized by rate limiting electron transfer (with α ~ 0.5), suggesting that while ring opening is extremely rapid, the radical anions do have a discrete lifetime (i.e., electron transfer and ring opening are not concerted). Utilizing homogeneous redox catalysis, rate constants for electron transfer between 1a, 1b, and 1c and a series of aromatic radical anions were measured; reduction potentials and reorganization energies were derived from these rate constants by using Marcus theory.
- Phillips, J. Paige,Gillmore, Jason G.,Schwartz, Phillip,Brammer Jr., Larry E.,Berger, Daniel J.,Tanko
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p. 195 - 202
(2007/10/03)
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- Novel Reduction of 2,6-Di-t-butyl-p-quinols with Sodium Borohydride
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Reduction of 2,6-di-t-butyl-p-quinols with NaBH4 results unexpectedly in the regio- and stereoselective formation of the corresponding dihydro-p-quinols.The novel reduction occurs via a quinoxyborohydride anion intermediate, which regulates the stereochemistry of the 4- and 6-positions in the products.Aromatization of the products is blocked by the t-butyl groups.
- Nishinaga, Akira,Kojima, Shinya,Mashino, Takahiro,Maruyama, Kazushige
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p. 961 - 964
(2007/10/02)
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- Peroxy Esters. 9. Base- and Radical-Induced Decomposition of 1-Alkyl-3,5-di-tert-butyl-4-oxo-2,5-cyclohexadienyl 3,5-Di-tert-butyl-4-hydroxyperbenzoates
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The title peroxy esters 1, when deprotonated with t-BuOK in DMF to the corresponding phenolate anions, decompose even at -78 deg C to give compounds 2-10.These compounds result undoubtedly from homolysis of the peroxy bond in 1, indicating that the generation of a carbanion at the α-position of the acyl group in peroxy esters (via resonance in the present case) induces ready homolysis of the peroxy bond.The oxidation of 1 with one-electron oxidizing agents gives rise to the corresponding phenoxy radicals, which also induce homolysis of the peroxy bond.
- Nishinaga, Akira,Nakamura, Koichi,Matsuura, Teruo
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p. 3700 - 3703
(2007/10/02)
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- Peroxy Esters. 8. Base-Catalyzed Rearrangement of Peroxy Esters: Formation of Alkoxyacetic Acid Derivatives
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p-Peroxyquinol esters derived from base-catalyzed oxygenation of 4-alkyl-2,6-tert-butylphenols followed by Schotten-Baumann acylation undergo a novel base-catalyzed rearrangement with t-BuOK in N,N-dimethylformamide to give p-quinoxyacetic acid derivatives in excellent yield.The same base-catalyzed rearrangement was also observed with tert-butyl peroxy esters.The base-catalyzed reaction of peroxy esters depended strongly on the nature of the acyl group in the esters and the base used and is suggested to involve homolysis of the peroxy bond.
- Nishinaga, Akira,Nakamura, Koichi,Matsuura, Teruo
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p. 3696 - 3700
(2007/10/02)
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