Design, synthesis and structure-activity relationships of novel ALS inhibitors

The paper describes the biophore models of sulfonylurea, imidazolinone, triazolopyrimidinesulfonamide and 5-pyrimidyltriazolo-3-sulfonamides established by the Apex-3D method. A series of N-phenylsulfonyl-N'-(thiadiazol-2-yl) oxamides and three types of triazolopyrimidinesulfonamide were synthesised and their herbicidal activities determined to assess the validity of the model. In general, the model gave useful leads to activity, although the actual level was not always predicted accurately. In only a few cases did compounds predicted as being active prove to be inactive in the bioassay, and compounds with little or no activity were clearly indicated, As a result of this work, the compound N,N'-[1-(5,7-dimethyl-1,2,4-triazolo[1,5-a]pyrimidin-2-ylthio)butane-2,3-di-imino]bis(2-chlorobenzenesulfonamide) was selected as showing good activity against a range of species, and will be used as a lead for further development, (C) 2000 Society of Chemical Industry.