Synthesis and insecticidal evaluation of novel cyanopyridine derivatives against Aphis gossypii

Abstract

Another important factor driving the development of new therapeutic and insecticidal agents is the rapid emergence of resistance to conventional pesticides and antibiotics. One promising strategy for addressing this challenge is the exploration of new chemical scaffolds with diverse modes of action. In this study, a series of pyridine derivatives was synthesized efficiently using ultrasound-assisted technology as an alternative to conventional synthetic methods. The compounds were prepared through a simple four-component reaction involving substituted aromatic benzaldehydes, aryl acetyl compounds, sodium alkoxides, and malononitrile. All synthesized derivatives exhibited insecticidal activity against both nymphal and adult stages of the cotton aphid, Aphis gossypii. These pyridine derivatives were designed as structural analogs of neonicotinoid insecticides, and their toxicity toward A. gossypii was evaluated under laboratory conditions. Among the tested compounds, if and ic demonstrated the highest insecticidal potency, with LC₅₀ values of 0.102 and 0.108 mg/L, respectively. The findings highlight the potential of these pyridine-based compounds as promising candidates for the discovery and development of novel insecticidal agents. Furthermore, the effects of compounds ib, ic, and if were investigated at sublethal concentrations below their respective LC₅₀ values to assess their additional biological effects on the tested aphid populations. KEY WORDS: Insecticidal activity, Cotton aphid, Pyridine, Neonicotinoids, Aphis gossypii Bull. Chem. Soc. Ethiop. 2026, 40(12), 2671-2684.                                                                          DOI: https://dx.doi.org/10.4314/bcse.v40i12.12