| Identification | Back Directory | [Name]
demephion-O | [CAS]
682-80-4 | [Synonyms]
demephion-O
Thiophosphoric acid O,O-dimethyl O-[2-(methylthio)ethyl] ester
Phosphorothioic acid, O,O-dimethyl O-[2-(methylthio)ethyl] ester
demephion-O (ISO) O,O-dimethyl O-2-methylthioethyl phosphorothioate | [EINECS(EC#)]
211-666-9 | [Molecular Formula]
C5H13O3PS2 | [MOL File]
682-80-4.mol | [Molecular Weight]
216.26 |
| Hazard Information | Back Directory | [Description]
Demephion-O is an obsolete insecticide. Other than having a moderate aqueous solubility, very little data is available regarding its environmental fate or ecotoxicology. Demephion-O is an acetylcholinesterase inhibitor and a neurotoxin. | [Definition]
ChEBI: Demephion-O is an organic thiophosphate. | [Production Methods]
Demephion O, the oxon isomer of demephion, was produced using the same multipurpose plant chemistry that supported other oxon/thiono organophosphates of the mid 20th century. Industrial manufacture began with preparation of the O,O diethyl phosphorochloridate intermediate, typically formed by reacting phosphorus oxychloride with ethanol under strictly anhydrous, acid scavenged conditions. In parallel, the dimethylamino substituted sulphide/oxide side chain was synthesised from the appropriate chloroalkyl precursor. These components were then coupled in a controlled nucleophilic substitution step, usually in aromatic or chlorinated solvents, with careful temperature management to control hydrogen chloride evolution. Because demephion O is the fully oxidized (P=O) isomer, its production required either starting from the oxo chloridate or oxidising the thiono analogue after coupling, a step that was typically performed with mild oxidants to avoid over oxidation. After reaction completion, the mixture underwent neutralisation, phase separation, solvent exchange, and vacuum stripping to yield technical grade demephion O. | [Mechanism of action]
Systemic. Acetylcholinesterase (AchE) inhibitor. | [Pesticide Type]
Insecticide; Acaricide |
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