Metabolic pathway
Dimethylvinphos is the dimethyl analogue of chlorf envinphos; however,
in contrast to that compound the technical material consists of >95% of
the Z-isomer. Dimethylvinphos is also a close chemical analogue of tetrachlorvinphos,
having a 2,4-dichloro substitution pattern rather than
2,4,5-trichloro on the phenylvinyl moiety and consequently the metabolism
of dimethylvinphos is qualitatively very similar to that of the other
two insecticides. In mammals, the principal route of metabolism of
dimethylvinphos is via oxidative and glutathione S-alkyltransferase
mediated demethylation to desmethyl dimethylvinphos which is hydrolysed
to 2,2',4'-trichloroacetophenone. This is further metabolised via a
series of glutathione mediated reactions to 1-(2,4-dichlorophenyl)ethanl-ol and 2,4-dichlorophenylethane-1,2-diol which are conjugated as the
glucuronides and excreted. 2,4-Dichlorophenylethane-1,2-diol may be
further metabolised by oxidation to 2,4-dichloromandelic which is
excreted or decarboxylated to 2,4-dichlorobenzoic acid.
