Phosdrin (0,0-Dimethyl 1l-carbomethoxy-1-propen-2-yl phosphate) 
Information on the metabolism of phosdrin in plants is not complete. 
However, the limited information available indicated that this dei haa 
was decomposed in plants by an initial enzymatic hydrolysis of the carboxylic 
ester to form the corresponding free acid. This was quickly followed 
by cleavage of the vinyl phosphate bond and decarboxylation. The finding 
of desmethyl phosdrin acid in some studies indicated that there were at 
least two paths for degradation of phosdrin in plants (Casida et al., 
1956; Spencer and Robinson, 1960). 
When labeled phosdrin was fed to cows, blood levels of phosdrin 
metabolites reached a peak between 2 and 4 hours after administration 
and the blood was essentially free of radiation within 24 hours. Within 
3 days, 77% of the administered dose was excreted. Half this was excreted 
via the urine within 12 hours. All radioactivity in the feces was present 
as hydrolysis products. Dimethyl phosphoric acid was identified in urine 
from a cow treated with phosdrin and in human plasma incubated with phos-~ 
drin (Casida et al., 1958). 
a ae O CH3 Q 
(CH30)  -P-0-¢=cH-C-COCH3—> (CH30) 9-P-0-¢=cH-8-on- 
Phosdrin jee Phosdrin Acid 
rt Toye ‘Sie a 
(CH.,0)-P-OH + HO-C=CH-C” cH. 0-b-0-c=cH-c/ 
3°°2 ‘\ 3 \ 
OH bu OH 
ye | Desmethyl 
Phosdrin acid 
CH3 
1 
HO-C=CH, of co, 
136 
