7497. Pirimiphos-methyl

Nomenclature

CAS number: 29232-93-7
O-[2-(Diethylamino)-6-methyl-4-pyrimidinyl]phosphorothioic acid O,O-dimethyl ester; O,O-dimethyl O-[2-(diethylamino)-6-methyl-4-pyrimidinyl]phosphorothioate; PP-511; Actellic (Syngenta); Blex (Zeneca); Dominator (Schering-Plough); Silosan (Zeneca).
C11H20N3O3PS; mol wt 305.33.
C 43.27%, H 6.60%, N 13.76%, O 15.72%, P 10.14%, S 10.50%.

Description and references

Organophosphate insecticide; cholinesterase inhibitor. Prepn: S. P. Sharpe, B. K. Snell, GB 1204552; eidem, US 3651224 (1970, 1972 both to ICI). Description of properties and analytical methods: D. J. W. Bullock, Anal. Methods Pestic. Plant Growth Regul. 8, 185-206 (1976). Toxicity study: P. S. Rajini, M. K. Krishnakumari, J. Environ. Sci. Health B23, 127 (1988). Photodegradation study: J. M. Herrmann et al., Catal. Today 54, 353 (1999) DOI. Efficacy in stored wheat: F. Huang, B. Subramanyam, Pest Manag. Sci. 61, 356 (2005).

Chemical structure

Properties

Straw-colored liquid. mp 15°. d30 1.157. nD24 1.5291. Vapor pressure at 30°: 1.1×10-4 Torr. Soly in water at 30°: 5 mg/l. uv max: 248 nm (ε 20761). LD50 in male, female rats (mg/kg): 1861, 1667 orally (Rajini, Krishnakumari).

Derivative

O,O-Diethyl analog.

Nomenclature

CAS number: 23505-41-1
Pirimiphos-ethyl; PP-211; Primicid.
C13H24N3O3PS; mol wt 333.39.
C 46.83%, H 7.26%, N 12.60%, O 14.40%, P 9.29%, S 9.62%.

Description and references

Prepn: B. K. Snell, S. P. Sharpe, GB 1205000 (1970 to ICI). Persistence and degradn in soil: D. L. Suett, Pestic. Sci. 6, 385 (1975) DOI. Review of properties and analytical methods: D. J. W. Bullock, Anal. Methods Pestic. Plant Growth Regul. 8, 171-184 (1976).

Properties

Straw-colored liquid, dec >130°. d20 1.14. nD25 1.520. Vapor pressure at 25°: 2.9×10-4 mm Hg. Miscible with most organic solvents. Soly in water (30°): 1 ppm. Weakly basic. uv max (methanol): 248 nm (ε 21300). LD50 in rats, mice, guinea pigs (mg/kg); 140-200, 105, 50-150 orally; dermally in rats: 1000-2000 mg/kg (Bullock).

Use

Insecticide.

Therapeutic Category (Veterinary)

Ectoparasiticide.