Dibenzo-p-dioxin (Diphenylene Dioxide) 誘導体の研究 (第30報)

1,2,3,6,7,8-Hexamethoxydibenzo-p-dioxinおよび1,2,3,6,7,8-Hexamethoxy-4,9-diethyldibenzo-p-dioxinの合成

抄録

Tomita had discovered that all substances possessing a dibenzo-p-dioxin skeleton (XVI) gave blue to bluish green coloration with conc. sulfuric acid and potassium nitrate or other oxidation reagents and this is utilized for qualitative reaction of such compounds as the diphenylene dioxide reaction. However, octachlorodibenzo-p-dioxin (XVII) and octabromodibenzo-p-dioxin (XVII) prepared by the present author and others do not undergo this coloration reaction. In order to examine whether this failure is due to the insolubility of (XVII) and (XVIII) in conc. sulfuric acid or because these compounds cannot take the quinoid form required for coloration reaction in general by substitution of all the hydrogens in the benzene ring with halogen atoms, 1, 2, 3, 6, 7, 8-hexamethoxydibenzo-p-dioxin (VIII) and 1, 2, 3, 6, 7, 8-hexamethoxy-4, 9-diethyldibenzo-p-dioxin (XIII) were prepared by the route shown in Chart 1. Of these compounds, (VIII) naturally colored bluish green to this reaction but (XIII) colored violet, contrary to the usual coloration of blue, bluish green, or green in this reaction. Consequently, the reason for failure of the octahalogen derivatives (XVII and XVIII) to show this diphenylene dioxide reaction is due to their complete insolubility in conc. sulfuric acid.