Methomyl

Methomyl ^[1]

(E)-Methomyl
(Z)-Methomyl
Names
IUPAC name (E,Z)-methyl N-{[(methylamino)carbonyl]oxy}ethanimidothioate
Other names Lannate, Mesomile, Methomex, Nudrin
Identifiers
CAS Number	16752-77-5  Y
3D model (JSmol)	Interactive image
ChEBI	CHEBI:6835  N
ChEMBL	ChEMBL552761  N
ChemSpider	3966  N
ECHA InfoCard	100.037.089
PubChem CID	5353758
CompTox Dashboard (EPA)	DTXSID1022267
InChI InChI=1S/C5H10N2O2S/c1-4(10-3)7-9-5(8)6-2/h1-3H3,(H,6,8) N Key: UHXUZOCRWCRNSJ-UHFFFAOYSA-N N InChI=1/C5H10N2O2S/c1-4(10-3)7-9-5(8)6-2/h1-3H3,(H,6,8) Key: UHXUZOCRWCRNSJ-UHFFFAOYAU
SMILES CNC(=O)ON=C(C)SC
Properties
Chemical formula	C5H10N2O2S
Molar mass	162.20
Appearance	White crystalline solid [2]
Odor	Slight, sulfur-like [2]
Density	1.2946 g/cm3
Melting point	78 to 79 °C (172 to 174 °F; 351 to 352 K)
Solubility in water	58 g/L
Vapor pressure	0.00005 mmHg (25°C) [2]
Hazards
Flash point	Noncombustible [2]
NIOSH (US health exposure limits):
PEL (Permissible)	none [2]
REL (Recommended)	TWA 2.5 mg/m3 [2]
IDLH (Immediate danger)	N.D. [2]
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

Methomyl is a carbamate insecticide introduced in 1966. It is highly toxic to humans, livestock, pets, and wildlife. ^[3] The EU imposed a pesticide residue limit of 0,01 mg/kg for all fruit and vegetables. ^[4]

Methomyl is a common active ingredient in commercial fly bait, for which the label instructions in the United States warn that "It is a violation of Federal Law to use this product in a manner inconsistent with its labeling." "Off-label" uses and other uses not specifically targeted at problem insects are illegal, dangerous, and ill-advised. ^{[5] [6]}

Use

Methomyl is a broad-spectrum insecticide that is used to kill insect pests. ^[7] Methomyl is registered for commercial/professional use under certain conditions on sites including field, vegetable, and orchard crops; turf (sod farms only); livestock quarters; commercial premises; and refuse containers. Products containing 1% Methomyl are available to the general public for retail sale, but more potent formulations are classified as restricted-use pesticides: not registered for homeowner or non-professional application. ^[7] However, Heliothis virescens developed a resistance to methomyl within 5 years. ^[8] Other species like Helicoverpa assulta also developed resistance after exposure. ^[9]

Toxicity

In acute toxicity testing, methomyl is placed in EPA Toxicity Category I (the highest toxicity category out of four) via the oral route and in eye irritation studies. ^[7] It is in lower Toxicity Categories for inhalation (Category II), acute dermal effects (Category III), and acute skin irritation (Category IV). Methomyl is not likely to be a carcinogen (EPA carcinogen Category E). ^[7]

Ecotoxicity

Methomyl has low persistence in the soil environment, with a reported half-life of approximately 14 days. ^[10] Because of its high solubility in water, and low affinity for soil binding methomyl may have potential for groundwater contamination. ^{[7] [11]} The estimated aqueous half-life for the insecticide is 6 days in surface water and over 25 weeks in groundwater. ^[11]

Synthesis

First prepare thioester:

Second prepare oxime from thioester:

Third prepare product from methyl isocyanate and the finished oxime:

Trade names

Common names for methomyl include metomil and mesomile. Trade names include Acinate, Agrinate, DuPont 1179, Flytek, Kipsin, Lannate, Lanox, Memilene, Methavin, Methomex, Nudrin, NuBait, Pillarmate and SD 14999 ^[11]

References

1. Merck Index, 11th Edition, 5905
2. NIOSH Pocket Guide to Chemical Hazards. "#0387". National Institute for Occupational Safety and Health (NIOSH).
3. Methomyl at Extension Toxicology Network
4. "EU pesticides database".
5. Conservation Warden Warns: Fly bait to control wild animals – illegal and a bad idea (Wisconsin Department of Natural Resources)
6. "Farm stores promoted poisoning raccoons, state chemist says". Archived from the original on 2015-09-24. Retrieved 2012-08-09.
7. EPA R.E.D. FACTS - Methomyl (PDF) (Technical report). U. S. Environmental Protection Agency. December 1998. EPA-738-F-98-019.
8. Blanco, Carlos (2012). "Heliothis virescens and Bt cotton in the United States". GM Crops & Food: Biotechnology in Agriculture and the Food Chain. 3 (3): 201–212. Bibcode:2012GMCFB...3..201B. doi: 10.4161/gmcr.21439 . PMID   22892654.
9. Wang, Kai-Yun; Zhang, Yong; Wang, Hong-Yan; Xia, Xiao-Ming; Liu, Tong-Xian (2010-01-01). "Influence of three diets on susceptibility of selected insecticides and activities of detoxification esterases of Helicoverpa assulta (Lepidoptera: Noctuidae)". Pesticide Biochemistry and Physiology. 96 (1): 51–55. Bibcode:2010PBioP..96...51W. doi:10.1016/j.pestbp.2009.09.003.
10. Howard, P. H. (1991). Handbook of Environmental Fate and Exposure Data for Organic Chemicals: Pesticides. Chelsea, MI: Lewis Publishers. pp. 3–15.
11. "Extoxnet Pip - Methomyl".

External links

• Methomyl in the Pesticide Properties DataBase (PPDB)