- STABILIZER FOR ORGANIC MATERIALS
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The present invention provides a compound represented by the formula (I): wherein R1-R4 are each independently a t-butyl group or a t-pentyl group.
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Paragraph 0092
(2018/07/31)
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- Selective Preparation. 31. Oxidative Coupling of 2-Halo-4,6-di-tert-butylphenols with Potassium Hexacyanoferrate (III) in Benzene
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When 2-bromo-4,6-di-tert-butylphenol (1b) was treated with K3Fe(CN)6 in benzene, 1,4-dihydro-4-bromo-2,4,6,8-tetra-tert-butyl-1-oxodibenzofuran (3) was obtained in 81percent yield together with a small amount of 2,4,6,8-tetra-tert-butyldibenzofuran (4).Heating of 3 in primary alcohols such as methanol and ethanol afforded the corresponding 1,4-dihydro-4-alkoxy-2,4,6,8-tetra-tert-butyl-1-oxodibenzofuran (9) in good yields.However, treatment of 3 with boiling isopropyl alcohol gave in 85percent yield 1-hydroxy-2,4,6,8-tetra-tert-butyldibenzofuran (5), which afforded 1-hydroxydibenzofuran (6) by its AlCl3-catalyzed trans tert-butylation in toluene.Compound 6 was obtained also by the AlCl3-catalyzed trans alkylation of 3.Similar trans alkylation of 4 afforded dibenzofuran (19). 1-Hydroxy-4-methoxy- (11) and 1,4-dihydro-1,4-dioxo-2,6,8-tri-tert-butyldibenzofuran (12) were also prepared from compound 3.Similar oxidation of 2-chloro-4,6-di-tert-butylphenol (1c) afforded 6,6'-bis (22) and 2,4-di-tert-butyl-4-chloro-6-(2,4-di-tert-butyl-6-chlorophenoxy)-cyclohexa-2,5-dien-1-one (23) in 23percent and 53percent yields, respectively.However, oxidation of 2-fluoro-4,6-di-tert-butylphenol (1d) gave only one product, 2,4-di-tert-butyl-4-fluoro-6-(2,4-di-tert-butyl-6-fluorophenoxy)-cyclohexa-2,5-dien-1-one (36), in 63percent yield.The mechanisms of oxidation of 2-halo-4,6-di-tert-butylphenols with K3Fe(CN)6 in benzene were also discussed in this paper.
- Tashiro, Masashi,Yoshiya, Haruo,Fukata, Gouki
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p. 3784 - 3789
(2007/10/02)
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