6051. Methyl Demeton

Nomenclature

CAS number: 8022-00-2
Phosphorothioic acid O-[2-(ethylthio)ethyl] O,O-dimethyl ester mixt with S-[2-(ethylthio)ethyl] O,O-dimethyl phosphorothioate; demeton-methyl; methyl-mercaptophos; methyl systox; Bayer 21/116; Meta-Systox.
C6H15O3PS2; mol wt 230.29.
C 31.29%, H 6.57%, O 20.84%, P 13.45%, S 27.85%.

Description and references

Cholinesterase inhibitor. Isomeric mixture consisting of demeton-O-methyl and demeton-S-methyl (O(and S)-[2-(ethylthio)ethyl] O,O-dimethyl phosphorothioate). Ref: Henglein, Schrader, Z. Naturforsch. 10b, 12 (1955). Prepn: GB 814332 (1959 to Bayer). Toxicology studies: M. Vandekar, Br. J. Ind. Med. 15, 158 (1958); E. F. Edson, Pharm. J. 185, 361 (1960).

Chemical structure

Properties

Commercial product is a light yellow liquid. Hydrolyzed by alkali. LD50 in rats (mg/kg): 50-75 orally, 300-400 dermally (Edson).

Derivative

Demeton-O-methyl.

Nomenclature

CAS number: 867-27-6

Properties

Colorless oil, bp0.15 74°. d420 1.190. nD20 1.5063. Soly in water at room temp: 330 ppm. Soluble in organic solvents.

Derivative

Demeton-S-methyl.

Nomenclature

CAS number: 919-86-8

Properties

Pale yellow oil, bp0.15 89°. d420 1.207. nD20 1.5065. Soly in water at room temp: 3,300 ppm. Sol in organic solvents. LD50 in rats (mg/kg): 40 orally, 85 dermally (Edson).

Caution

Potential symptoms of overexposure are irritation of eyes, skin; aching eyes, rhinorrhea; nausea, headache, dizziness, vomiting. See NIOSH Pocket Guide to Chemical Hazards (DHHS/NIOSH 97-140, 1997) p 206.

Use

Insecticide.