Synthesis and herbicidal activities of 4-alkoxy/benzyloxyphenyltetrazoles and 1,3,4-oxadiazoles

Tetrazoles and 1, 3, 4-oxadiazoles are important heterocyclic compounds with a wide range of pharmaceutical and biological activity. Their syntheses and herbicidal activity have been of interest for a long time. In our previous research, a series of 4-alkoxy (benzyloxy) benzamidines were synthsized and showed a favourable herbicidal activity and KARI inhibitory activity. For searching potent herbicidal activity compounds, in this paper, five 4-alkoxy/benzyloxyphenyltetrazoles and seventeen new 2-substituted-5-(4-alkoxy/benzyloxy) phenyloxadiazoles were designed on the basis of the structure of 4-alkoxy (benzyloxy) benzamidine and synthesized via 4-cyanophenol as the starting material. All synthesized novel compounds were confirmed by elemental analysis, H-1 NMR and MS. The preliminary herbicidal assay indicates that some of them displayed a good herbicidal activity on di-cotyledonous rape(Brassica campestris) and mono-cotyledonous barnygrass(Echinochloa crusgalli).