2032-65-7

ChEBI: A carbamate ester obtained by the formal condensation of the phenolic group of 3,5-dimethyl-4-(methylsulfanyl)phenol with the carboxy group of methylcarbamic acid.

Insecticide; molluscicide; bird repellent.

White crystalline powder with a mild odor. Used as an insecticide and immobilizing agent for birds, acaricide and molluscicide.

MERCAPTODIMETHUR is a carbamate ester. Carbamates are chemically similar to, but more reactive than amides. Like amides they form polymers such as polyurethane resins. Carbamates are incompatible with strong acids and bases, and especially incompatible with strong reducing agents such as hydrides. Flammable gaseous hydrogen is produced by the combination of active metals or nitrides with carbamates. Strongly oxidizing acids, peroxides, and hydroperoxides are incompatible with carbamates.

As a carbamate insecticide, this compound is a reversible cholinesterase inhibitor and acts on the nervous system. It is classified as very toxic, and the probable oral lethal dose for humans is 50-500 mg/kg or between 1 teaspoon and 1 ounce for a 150 lb. adult.

A potential danger to those involved in the manufacture, formulation, and application of this nonsystemic acaricide and insecticide.

When heated to decomposition, MERCAPTODIMETHUR emits very toxic fumes of nitrogen and sulfur oxides.

If this chemical gets into the eyes, remove any contact lenses at once and irrigate immediately for at least 15 minutes, occasionally lifting upper and lower lids. Seek medical attention immediately. If this chemical contacts the skin, remove contaminated clothing and wash immediately with soap and water. Speed in removing material from skin is of extreme importance. Shampoo hair promptly if contaminated. Seek medical attention immediately. If this chemical has been inhaled, remove from exposure, begin rescue breathing (using universal precautions, including resuscitation mask) if breathing has stopped and CPR if heart action has stopped. Transfer promptly to a medical facility. When this chemical has been swallowed, get medical attention. Give large quantities of water and induce vomiting. Do not make an unconscious person vomit. Keep victim quiet and maintain normal body temperature. Effects may be delayed; keep victim under observation.

UN2757 Carbamate pesticides, solid, toxic, Hazard Class: 6.1; Labels: 6.1-Poisonous materials. UN2811 Toxic solids, organic, n.o.s., Hazard Class: 6.1; Labels: 6.1-Poisonous materials, Technical Name Required

Methiocarb was originally developed by Bayer as an insecticide. The bird-repellent properties of the compound were quickly recognized, however, and a number of applications for bird damage management followed (42).
Methiocarb is a secondary repellent, and repellency occurs through aversive conditioning, by which birds that feed on treated food become sick and associate either the food or characteristics of the food with the discomfort (21). As a result, affected birds learn to avoid that food item. Often the avoidance response is locationdependent. For example, common ravens (Corvus corax) that learn not to eat eggs at one site will still feed on eggs at a different location (43).

Methiocarb is a colorless crystalline powder.

In accordance with 40CFR 165 recommendations for the disposal of pesticides and pesticide containers. Must be disposed properly by following package label directions or by contacting your local or federal environmental control agency, or by contacting your regional EPA office. Consult with environmental regulatory agencies for guidance on acceptable disposal practices. Generators of waste containing this contaminant (≥100 kg/mo) must conform to EPA regulations governing storage, transportation, treatment, and waste disposal. Remove material with contaminated soil and place in impervious containers. May be incinerated in a pesticide incinerator at the specified temperature/dwell-time combination. Any liquids, sludges, or solid residues generated should be disposed of in accordance with all applicable federal, state, and local pollution control requirements. If appropriate incineration facilities are not available, material may be buried in a chemical waste landfill. May be amenable to biological treatment at a municipal sewage treatment plant. (Sax/DPIMR).

The industrial synthesis of methiocarb begins with the preparation of a substituted phenol, typically 3,5-dimethylphenol. This compound undergoes thiomethylation using reagents like methyl mercaptan or dimethyl sulfate to introduce the methylthio group at the para position. The resulting intermediate is then reacted with methyl isocyanate or methylcarbamoyl chloride to form the carbamate ester, a key functional group responsible for its pesticidal activity. The reactions are carried out under controlled temperature and pressure in organic solvents such as toluene or xylene, with catalysts and bases used to optimise yield and purity.

Acaricide, Molluscicide, Insecticide: Used to control slugs and snails, soil insects and spider mites in pome fruit, stone fruit, hops, strawberries, potatoes, beets, maize, vegetables and ornamentals. Also used as seed treatment to control fruit flies on maize and bird repellant on berries and cherries. Methiocarb producers deleted all food uses from their product labels between 1989-92. It is A U.S. EPA restricted Use Pesticide (RUP) except for residential application.

AI3-25726®; ALCO SLUB”M[C]; B 37344®; BAY 5024®; BAY 9026®; BAY 37344®; BAYER 37344®; DCR 736®; DRAZA®; DRAZA G MICROPELLETS®; H 321®; MESUROL®; METHIOCARBE®; OMS- 93®; PBI SLUG GARD®; PROVADA®; SD 9228®; SLUG-GETA®[C]

Non-systemic with neurotoxic contact and stomach action. Acetylcholinesterase (AChE) inhibitor.

Methiocarb is a carbamate, and its mode of action is via the inhibition of acetylcholinesterase at synapses in the nervous system. Unlike many cholinesterase-inhibiting compounds, however, the effects of methiocarb are rapidly reversible, and the animal experiences only transitory disruption.

Soil. Methiocarb was oxidized, probably by singlet oxygen, to the corresponding sulfoxide and trace amounts (<5% yield) of sulfone when sorbed on soil and exposed to sunlight. The photosensitized oxidation was faster in soils containing the lowest organic carbon content (Gohre and Miller, 1986).
Plant. On and/or in bean plants, the methylthio group is rapidly oxidized to the sulfoxide and sulfone (Abdel-Wahab et al., 1966) followed by hydrolysis yielding the corresponding thiophenol, methylsulfoxide phenol and methylsulphonyl phenol (Har
Photolytic. When methiocarb in ethanol was irradiated by UV light, only a few unidentified cholinesterase inhibitors were formed (Crosby et al., 1965).
Chemical/Physical. Emits toxic fumes of nitrogen and sulfur oxides when heated to decomposition (Sax and Lewis, 1987).

Methiocarb is oxidised to a sulfoxide and a sulfone in biological media. The resulting two carbamate esters and the parent compound are hydrolysed in soils and plants to the corresponding phenols. Hydroxylation of the N-methyl group on the carbamate function occurs in mammalian preparations in vitro.

Store at -20°C

Methiocarb is unstable in alkaline solution. Its DT₅₀ values at pH 4,7 and 9 (22 °C) are >1 year, 35 days and 6 hours, respectively. Photodegradation (DT₅₀ 6-16 days) contributes to the loss of methiocarb from the environment (PM).
River water containing methiocarb was stored in sunlight or artificial light. Samples were taken and analysed by TLC. Methiocarb was rapidly hydrolysed (half-life 3 days) to the phenol (2) which itself degraded (Eichelberger and Lichtenberg, 1971).

Insecticide; Molluscicide