Synthesis and QSAR of herbicidal 3-alkoxy-6-(substituted) phenoxypyridazines

A series of 3-alkoxyl-6-(substituted) phenoxypyridazines were synthesized i n good yields by a novel synthetic approach, the nucleophilic reaction of 3 , 6-bis-(substituted) phenoxypyridazines with alkoxides. Their pI(50) value against barnyard grass and greenhouse activity against barnyard grass, com mon crabgrass, rape, amaranth were tested. The results showed that some of them exhibited a higher activity than MH. The primary quantitative sturctur e activity relationship (QSAR) was discussed.