SYNTHESIS, CRYSTAL STRUCTURE AND HERBICIDAL ACTIVITY OF A SERIES OF [1,2,4]TRIAZOLO[1,5-a]PYRIMEDINE-2-SULFONAMIDE COMPOUNDS

With the aim of obtaining efficient, safe and environmentally friendly green herbicide, a series of [1,2,4]triazolo[1,5-a]pyrimidine-2-sulfonamide compounds (8a-8f) were synthesized by reacting 2-amino-5,7-(bis-substituted)1,2,4-triazolo[1,5-c]pyrimidine (4a and 4b) with 2-substituted-6-trifluoromethylbenzenesulfonyl chloride (7a-7c). And their structures were characterized by C-13-NMR, HRMS, FTIR, single-crystal X-ray diffraction, elemental analysis. Moreover, their herbicidal activities against six species of weeds were evaluated. Three target compounds such as 8a, 8c and 8e, exhibited significant postemergence herbicidal activity against some common dicotyledons and monocotyledons under different concentrations. The structure and activity relationship is discussed based on the herbicidal performances of the compounds with different substituents. The investigation results indicated that the above structures could serve as lead compounds for the development of new herbicides.