DESIGN, SYNTHESES AND BIOLOGICAL-ACTIVITY OF NOVEL HERBICIDES TARGETED ALS - IV - STUDIES ON THE CRYSTAL-STRUCTURE, QUANTUM-CHEMISTRY AND STRUCTURE-ACTIVITY RELATIONSHIP OF 1,2,4-TRIAZOLO[1,5-A]PYRIMIDINE-2-SULFONAMIDES COMPOUNDS

On the basis of determining the crystal structure of three kinds of th e title compounds displaying different herbicidal activities, semi - e mpirical AM1 method was applied to study the electronic structure of h erbicidal 1, 2, 4 - triazolo[1, 5 - a] pyrimidine - 2 - sulfonamides c ompounds. At the same time,the structure - activity relationships of t his kind of herbicides were also discussed in view of conformation and electronic structure. The results indicate that 1,2,4 - triazolo[1,5 - a]pyrimidinyl moiety might be an important active site, of which the potency of electric charge translocation has a great influence on the herbicidal activity of this kind of compounds.