Synthesis and herbicidal activity of N-(4′-substituted pyrimidin-2′-yl)2-methoxycarbonyl-5-[(un)substituted benzamido]phenylsulfonylurea derivatives

In order to search for ecologically-safer and environmentally-benign sulfonylurea herbicides, on the basis of study on the N-(4-methylpyrimidin-2-yl)-N' -(2-methoxycarbonyl phenylsulfonyl)urea, named monosulfuron, a commercialized herbicide invented by our laboratory, 26 novel benzenesulfonylurea compounds modified at the 5-position of the benzene ring were synthesized. The structures of all compounds synthesized were confirmed by elemental analysis, MS and H-1 NMR spectra. Herbicidal activity of the new compounds was determined by rape disc and pot bioassay experiments. The result indicated that when the substituent group at 5-position of the benzene ring was benzamide, the herbicidal activity was good compared to sulfometuron-methyl.