Bensulfuron-methyl (BSM) is a new kind of sulfonylurea herbicide widely used to control various weeds and sedges. It is moderately soluble in water, non-volatile and moderately mobile. It would not be expected to persistent in soil but could be persistent in water systems under certain conditions. It is not highly toxic to mammals. It also shows a low toxicity to birds and earthworms but is more of a concern to aquatic plants, algae and honeybees.
Pure product is white odorless solid, m.p. 185-188℃, vapor pressure 1.733×10-3Pa (20℃). Solubility: dichloromethane 11720mg/L, acetonitrile 5380mg/L, xylene 280mg/L, ethyl acetate 1660mg/L, acetone 1380mg/L, methanol 990mg/L, hexane 3.1mg/L, water 1200mg/L. Partition coefficient is 4.1, stable in slightly alkaline (pH=8) aqueous solution, slowly decomposed in acidic solution. The half-life is 11d at pH 5 and 143d at pH 7. The original drug is slightly light yellow.
Bensulfuron methyl (BSM) was the first sulfonylurea herbicide commercialized for use in rice, and it remains the dominant sulfonylurea for broadleaf and sedge weed control in this crop.
ChEBI: Bensulfuron-methyl is the methyl ester of bensulfuron. An acetolactate synthase inhibitor, it is used as a herbicide for the control of a variety of both annual and perennial weeds in crops, particularly wheat and rice. It is not licensed for use within the UK. It has a role as a herbicide, an agrochemical and an EC 2.2.1.6 (acetolactate synthase) inhibitor. It is a N-sulfonylurea, a member of pyrimidines, a methyl ester and an aromatic ether. It derives from a bensulfuron.
Moderately toxic by ingestion.When heated to decomposition it emits toxic vapors ofNOx and SOx.
Bensulfuron methyl is metabolized by mammals and
birds and the major metabolites identified include
mono-O-demethylated and 5-hydroxylated bensulfuron
methyl and 5-hydroxy-2-amino-3,5-
dimethoxypyrimidine. As bird metabolites, cleavage of
the pyrimidine ring of bensulfuron methyl is observed which results in two pyrimidine ring-opening
metabolites. In rice plants, bensulfuron methyl
undergoes rapid O-demethylation at one of the
methoxy groups on the pyrimidine ring which will
proceed through hydroxylation at the methyl group.
Alcoholysis and hydrolysis of bensulfuron methyl (H1)
involve mainly the breakdown of the urea moiety
which leads to several degradation products, some of
which are also identified as metabolites in mammals
and plants.
