Synthesis of Oxygenated Derivatives of 2,3,7,8-Tetrachlorodibenzo-p-dioxin

Four monomethoxy, five dimethoxy and four dihydroxy derivatives of polychlorodibenzo-p-dioxin have been synthesized, and their physical and spectral properties (NMR and MS) have been reported. The general method for the synthesis of specific mono- and dimethoxy derivatives in reasonable yields has been found to be the condensation of 4,5-dichlorocatechol with appropriately substituted o-chloronitrobenzenes. The monomethoxy derivatives thus prepared were demethylated by boron tribromidedimethyl sulfide. Several mono- and dihydroxypolychlorodibenzo-p-dioxins have been identified as metabolites of the highly toxic environmental contaminant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). However, most of these metabolites have not been fully characterized due to the lack of appropriate standards. The availability of these synthetic oxygenated derivatives of TCDD can be used to establish the structure and the potential toxicity associated with these metabolites.