Direct Formations of o-Tropoquinone Bisacetals from 2,3- and 2,7-Dimethoxytropones and p-Tropoquinone Bisacetals from 2-Bromo-7-methoxytropone by the Anodic Oxidation

Article abstract of DOI:10.1246/cl.1987.1931

Anodic oxidation of 2,7- and 2,3-dimethoxytropones gave the corresponding 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.