Bensulfuron methyl

Description

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.

The Uses of Bensulfuron methyl

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.

Definition

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.

Safety Profile

Moderately toxic by ingestion.When heated to decomposition it emits toxic vapors ofNOx and SOx.

Metabolic pathway

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.