Methomyl

Methomyl

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Names
IUPAC name (E,Z)-methyl N-{[(methylamino)carbonyl]oxy}ethanimidothioate
Other names Lannate, Mesomile, Methomex, Nudrin
Identifiers
CAS Number	16752-77-5 Y
ChEBI	CHEBI:6835 N
ChEMBL	ChEMBL552761 N
ChemSpider	3966 N
Jmol 3D model	Interactive image
PubChem	5353758
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 C/C(=N\OC(=O)NC)/SC
Properties
Chemical formula	C5H10N2O2S
Molar mass	162.20
Appearance	White crystalline solid
Odor	Slight, sulfur-like
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)
Vapor pressure	{{{value}}}
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. The EU and UK imposed a pesticide residue limit of 0.02 mg/kg for apples and oranges.

Methomyl is a common active ingredient in commercial fly bait, for which the label instructions 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.

Use

Methomyl is a broad-spectrum insecticide that is used to kill insect pests. 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.

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

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. 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).

Ecotoxicity

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

Synthesis

Methomyl can be produced by reaction of methyl isocyanate and methylthioacetaldoxime (also known as methomyl oxime).

First prepare ester

${{\text{H}}_{\text{3}}}\text{C-}\underset{\underset{\text{O}}{\mathop{\text{ }\!\!|\!\!\text{ }\!\!|\!\!\text{ }}}\,}{\mathop{\text{C}}}\,\text{-OH+HS-C}{{\text{H}}_{\text{3}}}\xrightarrow{\text{30--50 }\!\!~\!\!\text{ }\!\!{}^\circ\!\!\text{ C}\text{,-}{{\text{H}}_{2}}O}{{\text{H}}_{\text{3}}}\text{C-}\underset{\underset{\text{O}}{\mathop{\text{ }\!\!|\!\!\text{ }\!\!|\!\!\text{ }}}\,}{\mathop{\text{C}}}\,\text{-S-C}{{\text{H}}_{\text{3}}}$

Second prepare oxime from ester ${{\text{H}}_{\text{3}}}\text{C-}\underset{\underset{\text{O}}{\mathop{\text{ }\!\!|\!\!\text{ }\!\!|\!\!\text{ }}}\,}{\mathop{\text{C}}}\,\text{-S-C}{{\text{H}}_{\text{3}}}\text{+}{{\text{H}}_{\text{2}}}\text{NOH}\xrightarrow{-{{H}_{2}}O}\text{HO-N=}\underset{\text{C}{{\text{H}}_{\text{3}}}}{\mathop{\underset{\text{ }\!\!|\!\!\text{ }}{\mathop{\text{C}}}\,}}\,\text{-S-C}{{\text{H}}_{\text{3}}}$

Third prepare product from isocyanate and oxime. ${{\text{H}}_{\text{3}}}\text{C-N=C=O+HO-N=}\underset{\text{C}{{\text{H}}_{\text{3}}}}{\mathop{\underset{\text{ }\!\!|\!\!\text{ }}{\mathop{\text{C}}}\,}}\,\text{-S-C}{{\text{H}}_{\text{3}}}\xrightarrow{\text{C}{{\text{H}}_{\text{2}}}\text{C}{{\text{l}}_{\text{2}}}\text{,30--50 }\!\!~\!\!\text{ }\!\!{}^\circ\!\!\text{ C}}\text{Methomyl}$

External links

• Methomyl in the Pesticide Properties DataBase (PPDB)