Design, synthesis, insecticidal activities and translocation of amino acid–tralopyril conjugates as vectorizing agrochemicals

Conjugating amino acid moieties to active ingredients has been recognized as an effective method for improving the precise targeting of the active form to the specific site. Based on the vectorization strategy, a series of amino acid-tralopyril conjugates were designed and synthesized as novel proinsecticide candidates, with the potential capability of root uptake and translocation to the foliage of crops.Bioassay results showed excellent insecticidal activities of some conjugates, in particular, the conjugates 6b, 6e, and 7e, against the diamondback moth (Plutella xylostella), with equivalent insecticidal activity to chlorfenapyr (CFP). Importantly, conjugate 6e exhibited significantly higher in vivo insecticidal activity against P. xylostella than CFP. Furthermore, the systemic test experiments with Brassica chinensis demonstrated that conjugates 6e and 7e could be transported to the leaves, in contrast to CFP, which remained in the root.This study demonstrated the feasibility of amino acid fragment conjugation as a vectorization strategy for transporting non-systemic insecticides into the leaves of B. chinensis while maintaining in vivo insecticidal activity. The findings also provide insights for subsequent mechanism studies on the uptake and transport of amino acid-insecticide conjugates in plants. © 2023 Society of Chemical Industry.