Sulfometuron-methyl

The prodrug is white solid. m.p. 203～205℃, vapor pressure 7.39×10-14Pa, relative density 1.48. At 25℃, the solubility is: acetone 2.4g/kg, acetonitrile 1.5g/kg, ethanol 137mg/kg, ether 32mg/kg, xylene 37mg/kg, water 8mg/L (pH=5), 70mg/L (pH =7). The partition coefficient was 0.31 (pH=7). The hydrolysis half-life of the aqueous suspension was 18d at pH=5, and it was stable at pH=7-9. The half-life in soil was about 28d.

Metsulfuron-methyl is a sulfonylurea herbicide that inhibits the synthesis of branched-chain amino acids, thereby inhibiting cell division at the growing tips of plants, preventing the growth of weeds, and leading to chlorosis and necrosis. It is suitable for the control of annual and perennial grass weeds and broadleaf weeds in forestry.

ChEBI: Sulfometuron methyl is a benzoate ester that is the methyl ester of 2-{[(4,6-dimethylpyrimidin-2-yl)carbamoyl]sulfamoyl}benzoic acid. It has a role as a herbicide and an EC 2.2.1.6 (acetolactate synthase) inhibitor. It is a member of pyrimidines, a benzoate ester and a N-sulfonylurea. It is functionally related to a sulfometuron.

Sulfometuron-methyl is produced by reaction of 2-sulfonylisocyanate methylbenzoate with 2-amino-4,6-dimethylpyrimidine.

Herbicide: Used to control annual and perennial grasses and broadleaf weeds on landscapes, rights-of-ways, fence rows, forests, industrial structure areas and non-crop land. Not listed for use in EU countries. Registered for use in the U.S.

DPX-T5648®; KNOCKOUT®; LANDMARK® MP (sulfometuron-methyl + chlorsulfuron); OUST®; OUSTAR®; RIVERDALE®; STAMPRO®

Soil. In unsterilized soils, 58% of 14C-labeled sulfometuron-methyl degraded after 24 weeks. Metabolites identified were 2,3-dihydro-3-oxobenzisosulfonazole (saccharin), methyl-2-(aminosulfonyl)benzoate, 2-aminosulfonyl benzoic acid, 2-(((aminocarbonyl)amino)sulfonyl)benzoate and [14C]carbon dioxide. The rate of degradation in aerobic soils was primarily dependent upon pH and soil type (Anderson and Dulka, 1985). The reported half-life in soil was approximately 4 weeks (Hartley and Kidd, 1987).
Chemical/Physical. Sulfometuron-methyl is stable in water at pH values of 7 to 9 but is rapidly hydrolyzed at pH 5.0 forming methyl 2-(aminosulfonyl)benzoate and saccharin. When sulfometuron-methyl in an aqueous solution was exposed to UV light (λ = 300–400 nm), it degraded to the intermediate methyl benzoate which then mineralized to carbon dioxide (Harvey et al., 1985). The hydrolysis half-lives of metsulfuron-methyl at pH 5 and 25 and 45°C were 33 and 2.1 days, respectively. At pH 7 and 45°C, the hydrolysis half-life is 33 days (Beyer et al., 1988).

Sulfometuron methyl is relatively stable at neutral and basic pH and undergoes cleavage of the sulfonylurea linkage to yield methyl-2-(aminosulfonyl)benzoate and 4,6-dimethyl-2-aminopyrimidine as major hydrolysis products, and saccharin as the terminal product. These products are also observed as major degradation products in soils. In plants, monohydroxymethylsulfometuron methyl is the primary metabolite which is also identified as a mammalian and soil metabolite and undergoes further degradation by mammals to give 2-amino-4-hydroxymethyl-6- methylpyrimidine.