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KMID : 1059519950390080657
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Journal of the Korean Chemical Society
1995 Volume.39 No. 8 p.657 ~ p.665
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Oxidation of Benzyl Ethers in Sodium Hypochlorite Mediated Piperidine-1-oxyl System
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Cho Nam-Sook
Park Chan-Heun
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Abstract
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The oxidation of various benzyl ethers and benzyl alkyl ethers to benzoates has been studied in two-phase system of CH3CO2Et and aqueous NaOCl (6.6 mol eq.). The oxidant N-oxo-4-methoxy-2,2,6,6-tetramethylpiperidium bromide (N-oxoammonium salt) was prepared in situ and recycled by addition of 4-methoxy-2,2,6,6-tetramethylpiperidine-1-oxyl (0.03 mol eq., 4-methoxy-TEMPO), co-catalyst KBr (0.03mol eq.) and second oxidant NaOCl. Thus the catalytic amount of 4-methoxy-TEMPO was used. An adjustment of the pH value of below 8.0 was also required for this reaction with 2.5 hr of reaction time at 0∼5℃. Under these conditions benzyl ethers were oxidized to benzoates. The selectivity of oxidation of benzyl alkyl ethers is dependent on the acidity of hydrogen and steric effect of alkyl group.
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KEYWORD
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