Isolation of Natural Veratrylidenehydrazide Compound from <i>Wedelia Biflora</i> and Synthesis of Veratrylidenehydrazide Analogue: Investigation of Larvicidal Activity Against <i>Culex Quinquefasciatus</i> and Toxicity Analysis in Nontarget Aquatic S

Abstract In this study, veratrylidenehydrazide was isolated from Wedelia biflora , and compounds ( 1a , 2a , and 3a–j ) were synthesised to evaluate their larvicidal and antifeedant activities. Veratrylidenehydrazide 1a was verified using GC‐MS. The veratrylidenehydrazide analogues 2a and 3a–j were synthesised via a condensation method with yield range 71%–92%. The compounds ( 1a , 2a , and 3a–j ) were synthesised and characterised through FT–IR, 1 H NMR, 13 C NMR, mass spectrometry, and elemental analysis. Veratrylidenehydrazide 1a was verified using GC‐MS analysis. Natural veratrylidenehydrazide compound 1a and the synthesised veratrylidenehydrazide analogues ( 2a , 3a–j ) were screened for larvicidal activity against Culex quinquefasciatus . The larvicidal activity of compound 3g was found to be highly active, while low toxicity was observed against Oreochromis mossambicus nontarget aquatic species compared to natural veratrylidenehydrazide. Compound 3g exhibited a higher binding affinity (−8.8 kcal/mol) compared to standard of temephos (−4.5 kcal/mol), equipotential binding affinity against permethrin (−9.1 kcal/mol), and diflubenzuron (−8.5 kcal/mol). Lead molecules have larvicidal properties, and their use as insecticides makes them important.