2889. Demeton

Nomenclature

CAS number: 8065-48-3
Phosphorothioic acid O,O-diethyl O-[2-(ethylthio)ethyl] ester mixture with O,O-diethyl S-[2-(ethylthio)ethyl]phosphorothioate; mercaptophos; Bayer 8169; E-1059; Systox.
C8H19O3PS2; mol wt 258.34.
C 37.19%, H 7.41%, O 18.58%, P 11.99%, S 24.82%.

Description and references

Cholinesterase inhibitor. Isomeric mixture consisting of demeton-O and demeton-S (O,O-diethyl O(and S)-ethylmercaptoethyl thiophosphates). Another name for demeton-S is Isosystox. Prepn: Schrader, US 2571989 and US 2597534 (1951, 1952 both to Bayer); Gardner, Heath, Anal. Chem. 25, 1849 (1953). Toxicity study: T. B. Gaines, Toxicol. Appl. Pharmacol. 14, 515 (1969).

Chemical structure

Properties

Oily liq. Faint odor. bp2 134°. Virtually insol in water. Sol in ethanol, propylene glycol, toluene and similar hydrocarbons. Absorbed by plants, rendering the foliage and plant fluids toxic to insects. LD50 in female, male rats (mg/kg): 2.5, 6.2 orally; 8.2, 14 dermally (Gaines).

Caution

Potential symptoms of overexposure are miosis, aching eyes, rhinorrhea and headache; chest tightening, wheezing, laryngeal spasms, salivation and cyanosis; anorexia, nausea, vomiting, abdominal cramps and diarrhea; local sweating; muscle fasciculation, weakness and paralysis; giddiness, confusion and ataxia; convulsions, coma; low blood pressure; cardiac irregularities; irritation of eyes and skin. See NIOSH Pocket Guide to Chemical Hazards (DHHS/NIOSH 97-140, 1997) p 90.

Use

Insecticide.