DIOXATHION METABOLITES, PHOTOPRODUCTS, AND OXIDATIVE-DEGRADATION PRODUCTS

The trans and cis isomers of 2,3-p-dioxanedithiol S,S-bis(O,O-diethyl phosphorodithioate) (dioxathion acaricide and insecticide) are rapidly and extensively metabolized in rat liver microsome-NADPH systems and in rats in vivo by oxidation of the thionophosphorus moiety, forming oxons and dioxons, and probably also by oxidative O-deethylation and hydroxylation of the dioxane ring, the latter reaction forming labile intermediates that undergo ring cleavage and loss of both P moieties. The more toxic cis-dioxathion yields larger amounts of oxon and dioxon derivatives than the trans isomer in this liver enzyme system and on plant [bean] foliage and more 14CO2 from the ethoxy group in rats. 2-p-Dioxenethiol S-(O,O-diethyl phosphorodithioate) is degraded enzymatically and on plants to products which are the same as or analogous to those formed from the dioxathion isomers. The 3 phosphorodithioates yield toxic oxon derivatives as photoproducts. Synthesis procedures are given for [14C]ethoxy and [14C]ring preparations of these compounds and for several of their unlabeled oxidative degradation products, some obtained by peracid oxidation.