Herbicidal activity of sulfonylureas

Inhibits ALS activity by 50%. A good correlation exists between the herbicidal activity of sulfonylureas and their ability to inhibit acetolactate synthase (2). This in vitro assay using the target enzyme along with the three-dimensioFTI structure of the enzyme should aid in the generation of a substantial data base that can be used to design potent inhibitors. 

The herbicidal activity of sulfonylureas derived from phenylacetic esters is enhanced when the carboxylate moiety is tied up to form a butyrolactone ring. Extension of this structural modification to weakly herbicidal sulfonylureas derived from cinnamate esters gives vinylogous butyrolactones which display significantly improved efficacy. Structure-activity relationships in these two classes of compounds are discussed along with their synthesis involving a novel benzothiazinone dianion and rf/h9-metallation chemistry. 

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