3.5- Dibromo-2-methoxyphenol

Tribromo-m-cresol is oxidized by chromium trioxide in 70% acetic acid at 70-75 °C within 10 min to dibromo-m-toluquinone (3,5-dibromo-2-methyl-p-benzophenone) in 77% yield [559]. 2-BVomo-4-hy-droxy-5-methoxybenzyl alcohol treated with Fremy salt at pH 6 at room temperature for 1 h gives an 84% yield of 2-bromo-5-methoxy -benzo-quinone [487]. 4-Benzyl-2,6-dibromophenol, on oxidation with bromine in a sealed tube, yields 2,6-dibromophenylchinomethide [732] (equation 312). The oxidation of 2,5-di-tert-butyl-4-methoxyphenol with mercuric oxide or... 

Compound 3 was obtained in toluene, THF, and CHCI3 from reaction of SiCU and 8-hydroxyquinoline in the stoichiometric ratio of 1 2. In contrast, the analogous reaction with SiBr4 (in toluene) yields the tris-chelate complex 4. Consequently, the spectrum of the products is predominantly influenced by the reactivity of the silicon source, but a significant dependence on the used solvents was not observed. However, this conclusion is contrary to the results for ligand L H (reactions with 2-[(iV-benzylimino)phenylmethyl]-5-methoxyphenol) mentioned above. Compounds 3 and 4 were isolated, but we do not know exactly the configuration of the silicon-ligand sphere. We were not able to isolate the dibromo complex 5 from the mixture with 4. 

On controlled electrolysis (+880 mV vi. SCE 2 Fmol ) in MeOH, 2,6-dibromo-4-methoxyphenol (50) underwent 2e oxidation, followed by nucleophilic capture with MeOH to afford 2,6-dibromo-4,4-dimethoxy-2,5-cyclohexadien-l-one (51) in quantitative yield. 50 was also electrolyzed at a less positive potential (+440 mV ca 1 Fmor ) in MeOH containing AcOH-AcONHt to give two dienones (52 and 53) in 32 and 55% yields, respectively, as shown in Scheme 10. Herein, these products must be formed by C—O and C—C couphngs with bromine substitution, respectively. Therefore, the selective formation of 2e oxidation products or radical coupling dimers depends on the choice of the solvent. 

Me ether [77350-02-8]. 2 [(3,5-Dibromo-2-pyridinyl)azoy 5-methoxyphenol, 9CI. 3,5-Dibromo-2-(4-hydroxy-2-methoxyphenylazo)pyridine CijHgBrjNjOj M 387.030... 

Dibromo-2-pyridinyl)azo]-5-(dimethylamino)benzoic acid, D-00201 2-[(3,5-Dibromo-2-pyridinyl)azo]-5-methoxyphenol, in D-00200 (9,(9-Dibutyl phosphorodithioate K salt, in D-00241... 

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