in soil treated with it, or fromtreated seed. Conversion to the sulfone has not been shown 
in the soil and may take place only after entry into the plant tissue. 
The metabolism of ronnel (I) in cattle has been studied by Plapp and Casida (15), 
using P32 tagged material. Based on these studies, the following metabolic pathway is 
proposed: 
S 
cl cls S 
| 98 Was ; Pots 
-0-P en Se -0-P HO-P 
= Cy ‘ock, ee Sy Saees, ; Soci, 
cal | Cl | | 
I 
cl 0 Gas 2 
ll on | cll, | OCH 
a SG eras ei Nor tees OPC 
OCH OCH, OCH, 
cl © on Cl 
HO-P 
a ET 
The oxygen analog (II) was not isolated as an in vivo metabolite, but the inhibition 
of blood cholinesterase in the cows indicated its presence. Ronnel is a very weak 
cholinesterase inhibitor compared with its oxygen analog. This reaction and hydrolysis 
at the phosphorus-oxygen bond has been shown for other dialkyl aryl phosphorothioates,. 
Hydrolytic attack at the alkoxy group to yield a stable monoalkyl phosphorodiester had 
not been previously reported, The ultimate fate is probably degradation to phosphoric 
acid, which may be incorporated in phospholipids and phosphoproteins, 
Schradan is another compound that is nontoxic until it has undergone oxidation in the 
plant tissues, to convert it into a very potent insecticide. This compound illustrates the 
oxidative demethylation of an N-methyl phosphoramide, 
3 CH, CH, CH, 
Schradan 
CH.O CH 
Se Naa 
aw \) I7 sa 
3 P-0-P 3 CH,NHPO+HCHO 
Cd aut alysis 
Ss wee 
CH, ~. cH, 
109 
