A series of 3-arylalkylamino-6-chloropyridazines have been synthesized by the condensation of 3,6-dichloropyridazine with (un)substituted arylalkylamines in N,N-dimethylformamide (DMF) catalyzed by NaH at 120～130 ℃ or n-BuOH under reflux, and confirmed by ¹H NMR, IR spectra and elemental analyses. Preliminary bioassay showed that some of them have certain herbicidal activity against broad leaf grasses, for example, at the dosage of 10 µg•mL^－1, the inhibition percentage of compound 4f against Brassica napus reached 76.42%. Moreover, the structure-activity relationship was discussed.

Key words: herbicidal activity, structure-activity relationship, synthesis, 3-arylalkylamino-6-chloropyridazine