Title: Coumaphos
CAS Registry Number: 56-72-4
CAS Name: Phosphorothioic acid O-(3-chloro-4-methyl-2-oxo-2H-1-benzopyran-7-yl) O,O-diethyl ester
Additional Names: 3-chloro-7-hydroxy-4-methylcoumarin O-ester with O,O-diethyl phosphorothioate; 3-chloro-4-methylumbelliferone O-ester with O,O-diethyl phosphorothioate; O,O-diethyl O-(3-chloro-4-methyl-7-coumarinyl) phosphorothioate; O,O-diethyl O-(3-chloro-4-methylumbelliferone) thiophosphate; coumafos
Manufacturers' Codes: Bayer 21/199
Trademarks: Asuntol (Bayer); Baymix (Chemagro); Co-ral (Chemagro); Meldane (Chemagro); Muscatox (Bayer); Resitox (Bayer)
Molecular Formula: C14H16ClO5PS
Molecular Weight: 362.77
Percent Composition: C 46.35%, H 4.45%, Cl 9.77%, O 22.05%, P 8.54%, S 8.84%
Literature References: Prepn: Schrader, DE 881194; US 2748146 (1951, 1956 both to Bayer); Krueger et al., J. Agric. Food Chem. 7, 183 (1959). Toxicity: T. B. Gaines, Toxicol. Appl. Pharmacol. 14, 515 (1969).
Properties: Crystals, mp 91°. The commercial product may be slightly brownish. Practically insol in water. Somewhat sol in acetone, chloroform, corn oil. Stable in water. LD50 in female, male rats (mg/kg): 16, 41 orally (Gaines).
Melting point: mp 91°
Toxicity data: LD50 in female, male rats (mg/kg): 16, 41 orally (Gaines)
Use: Insecticide, nematocide.
Therap-Cat-Vet: Anthelmintic.
Coumaran Coumarilic Acid Coumarin-3-carboxylic Acid Coumestrol Coumetarol

CAS number 56-72-4 YesY
PubChem 2871
ChemSpider 2768 YesY
KEGG D07750 YesY
ATCvet code QP53AF08
Jmol-3D images Image 1
Molecular formula C14H16ClO5PS
Molar mass 362.77 g/mol
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Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
Infobox references

Coumaphos is a nonvolatile, fat-soluble phosphorothioate with ectoparasiticide properties: it kills insects and mites. It is well known by a variety of brand names as a dip or wash, used on farm and domestic animals to control ticks, mites, flies and fleas.[1]

It is also used to control Varroa mites in honey bee colonies, though in many areas it is falling out of favor as the mites develop resistance and as the residual toxicity effects are becoming better understood.[2][3]

In Australia, its registration as suited to home veterinary use was cancelled by the Australian Pesticides and Veterinary Medicines Authority in June 2004 after the manufacturer failed to show it was safe for use on pets.[4]

The compound has been linked to neurological problems in bees, and may be a factor in colony collapse.[5]