Abstract
Twenty-three O, O-dialkyl-O-(3-oxo-2-phenyl-2 H-pyridazine-6-yl) phosphorothioates (III) were prepared. Their insecticidal activities against rice plant pests and their toxicity to mice and small killifishes were studied. Of compounds tested, O, O-dimethyl-O-[2-(2-methylphenyl)-3-oxo-2H-pyridazine-6-yl] phosphorothioate (III-2) and O, O-diethyl-O-(3-oxo-2-phenyl-2H-pyridazine-6-yl) phosphorothioate (III-8) were the most effective against rice plant pests and these compounds showed low toxicity to mice and small killifishes. The relationships between chemical structure, activity and toxicity were examined.
