Synthesis And Herbicidal Activity Of Multi-substituted Triazolyl(Trifluoromethyl) Phenyl Ethers And Thiadiazole Derivativies

Phytoene dehydrogenase (PDS) is one of the key enzymes of carotenoid synthesis, this kind of inhibitor has high selectivity, excellent environmental compatibility, and it is a rapid developde novel bleaching herbicide. It was found that3-trifluoromethylphenyl moiety is the important active groups of this type of inhibitors. Heterocyclic compounds play an important role in drug development. We introduced1,2,4-trizole, pyridine into the biphenyl derivatibes and they are the PDS inhibitors, designded and synthesised eleven1,2,4-trizole compounds:5-aryl-4-phenyl(benzyl)-3-(3-triflouromethyl)phenoxyl-1,2,4-triazole (Ⅲ-la～Ⅲ-li).Pyrimidine is a very important heterocyclic compounds, widely used in the field of medicine and pesticides, a large number of studies have shown that these compounds have good biological activity, such as insecticidal, herbicidal, anticancer.1,3,4-thiadia-zole derivatives have many pharmacological activities, such as anticancer, bactericidal, antiviral. According to the principle of combination of bioactive substructure, with these two important bio-active groups and urea bridge, we designed and synthesised eight urea compounds:N-{2-[2-(4,6-dimethoxypyrimidin-2-yloxy) phenyl]-1,3,4-thiadiazol-5-y1}-N’-phenylurea(alkylurea)(Ⅱ-4a～Ⅱ-4h).According to the principle of combination of bioactive substructure, we introduced1,3,4-thiadiazole and pyrimidine into phenoxy acid designed and synthesised nine phen-oxy propionamide compounds:N-{2-[2-(4,6-dimethoxypyrimidin-2-yloxy) phenyl]-1,3,4-thiadiazol-5-yl}-2-phenoxypropanamide (Ⅲ-la～Ⅲ-li).The structures of all target compounds have been confirmed by1HNMR and elemental analysis, some of them were also characterized by MS and IR spectroscopy, their spectral properties, synthetic methods and reaction conditions were also studied. In addition, the preliminary herbicidal activities of the target compounds were evaluated. The results show that some compounds displayed good herbicidal activity, and their structures and herbicidal activity relationships were also investigated.