Methyl Paraphonothion [0-methyl O-p-nitrophenyl methylphosphonothionate ] 
Pp 32_] abeled methyl paraphonothion was fed to Swiss mice. Urine and 
feces were collected and analyzed for excreted P?2 compounds. There was 
no evidence of degradation of the P-CH3 bond. All compounds were identi- 
fied as hydrolysis products. Methyl phosphonic acid and its methy ester 
were present in the highest proportions at the three dosage levels tested. 
Additionally, 0-methyl methylphosphonothioate, desmethyl methyl paraphono- 
thion, its oxon analog, the desmethyl oxon analog, and two unidentified 
compounds were observed (682). 
i 0 
nif o-€ re, acts 0- C802 <p ato Co, 
: 
OCH3 H 
Methy1 Desmethyl Desmethyl 
paraphonothion paraphonothion oxon analog 
Y ™ cu,-b- bom \ 
CH a. -OH a CH, 3. -OH —> CH3- Son 
bon 
Ni Oxon ie wt Oct bi 
Methyridine [2-(2-methoxyethy1)-pyridine ] 
Methyridine and its metabolites were rapidly excreted in urine of 
sheep, calves, and small laboratory animals, irrespective of the route of 
dosing. Studies with labeled methyridine showed the presence of seven 
metabolites. Of these pyrid-2-yl ethanol, pyrid-2-yl acetic acid, and 
pyrid-2-yl acetylglycine were identified. Using liver homogenates, form- 
aldehyde was also observed. There were indications that the pyridine nu- 
cleus had been altered in two of the metabolites (208). 
C3. @) él | ; 
Sy CH, -CHy OCH, Spy CH2-CH 0H Sy CH2 -C-0H 
Methyridine 
258 
