Isomalathion

Isomalathion is an impurity found in some batches of malathion. Whereas the structure of malation is, generically, RSP(S)(OCH₃)₂, the connectivity of isomalathion is RSPO(SCH₃)(OCH₃). It arises by heating malathion. Being significantly more toxic to humans than malathion, it has resulted in human poisonings.^[1]

Isomalathion

Names
Preferred IUPAC name Diethyl {[methoxy(methylsulfanyl)phosphoryl]sulfanyl}butanedioate
Other names S-Methylmalathion
Identifiers
CAS Number	3344-12-5 Y
3D model (JSmol)	Interactive image
ChemSpider	82649 N
PubChem CID	91529
UNII	9XEP5P83AO N
CompTox Dashboard (EPA)	DTXSID9058363
InChI InChI=1S/C10H19O6PS2/c1-5-15-9(11)7-8(10(12)16-6-2)19-17(13,14-3)18-4/h8H,5-7H2,1-4H3 N Key: LPQDGVLVYVULMX-UHFFFAOYSA-N N InChI=1/C10H19O6PS2/c1-5-15-9(11)7-8(10(12)16-6-2)19-17(13,14-3)18-4/h8H,5-7H2,1-4H3 Key: LPQDGVLVYVULMX-UHFFFAOYAO
SMILES CCOC(=O)CC(C(=O)OCC)SP(=O)(OC)SC
Properties
Chemical formula	C10H19O6PS2
Molar mass	330.36 g/mol
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is YN ?) Infobox references

In 1976, numerous malaria workers in Pakistan were poisoned by isomalathion.^[2] It is an inhibitor of carboxyesterase.