Direct Formations of<i>o</i>-Tropoquinone Bisacetals from 2,3- and 2,7-Dimethoxytropones and<i>p</i>-Tropoquinone Bisacetals from 2-Bromo-7-methoxytropone by the Anodic Oxidation
作者:Akira Mori、Tadahiko Kubota、Seishi Kasai、Hitoshi Takeshita
DOI:10.1246/cl.1987.1931
日期:1987.10.5
Anodic oxidation of 2,7- and 2,3-dimethoxytropones gave the correspondong isomeric o-tropoquinone bisacetals, 2,2,7,7-tetramethoxycyclohepta-3,5-dienone and 2,2,3,3-tetramethoxycyclohepta-4,6-dienone in good yields. By H2SO4-treatment in AcOH–Ac2O, former afforded 4-acetoxy-2,7-dimethoxytropone, 2,5-diacetoxy-7-methoxytropone and 4,5-diacetoxy-3-methoxytropone, latter did no such product. Similar oxidation of 2-bromo-7-methoxytropone gave alternative p-tropoquinone bisacetal derivatives.
2,7-和2,3-二甲氧基托酮的阳极氧化得到相应的异构邻托醌二缩醛、2,2,7,7-四甲氧基环庚-3,5-二烯酮和2,2,3,3-四甲氧基环庚-4, 6-二烯酮收率良好。通过在AcOH-Ac2O中用H2SO4处理,前者得到4-乙酰氧基-2,7-二甲氧基托酮、2,5-二乙酰氧基-7-甲氧基托酮和4,5-二乙酰氧基-3-甲氧基托酮,后者则没有这样的产物。 2-溴-7-甲氧基托酮的类似氧化得到替代的对托醌二缩醛衍生物。