Synthesis, insecticidal activity, and phytotoxicity of novel chiral amides

Abstract

BACKGROUND The lesser grain borer, Rhyzopertha dominica (F.) (Coleoptera: Bostrychidae), is an important pest of stored grains worldwide. Chemical control is the main method used to manage this pest, but the continuous use of insecticides can lead to the selection of resistant R. dominica strains. Thus, there is a constant demand for the development of new insecticide molecules. This study describes the synthesis of 14 chiral amides and evaluation of their insecticidal activity against R. dominica. Their phytotoxicity to wheat (Triticum sativum) seeds is also evaluated. RESULTS In the screening assay, compounds 8i and 8j caused 100% and 87% mortality of R. dominica. These values did not differ from the mortality caused by Bifenthrin® (75%). Amide 8i presented similar toxicity (LD50 = 27.98 µmol g−1, CI95 = 25.14–30.71) and speed of action (LT50 = 22 h, CI95 = 19.34–24.66) to amide 8j (LD50 = 29.37 µmol g−1, CI95 = 27.43–31.09, and LT50 = 19 h, CI95 = 17.05–20.95) against the pest. Both amides inhibited less than 44% of wheat growth. CONCLUSION Among the tested amides, only 8i and 8j were effective in R. dominica control and presented no considerable phytotoxicity towards wheat seeds. Therefore, these amides are promising as insecticides for the management of R. dominica. © 2018 Society of Chemical Industry

Toxicity and Sublethal Effects of Phthalides Analogs to Rhyzopertha dominica

“…[8] Due to the high reproductive potential of stored product pests, [26] their control is recommended to be carried out quickly to prevent economic losses. [6] [27] In some industrialized countries like Canada and Australia, there is zero tolerance for insects in food grains. [28][29] Therefore, compounds that promote fast control should be considered as potential molecules to be explored for the management of stored grain pests.…”

Postharvest losses in food grains – A Review

“…The use of nano-engineered alumina insecticide powders was reported by Buteler et al (2020), the powder is removed at the end of storage using a pneumatic system to avoid safety issues. Chiral amides 8i and 8j effectively control Rhyzopertha dominica, a common wheat pest (Aguiar et al, 2019).…”

Crystal Prediction via Genetic Algorithms in a Model Chiral System

“…11, 12 Beyond new drug development and manufacture, crystal engineering (the selection of chemical substituents and processing conditions) as a route toward enantiopure chemical production is relevant to, for example, optoelectronic manufacturing, 13,14 catalysis, 15 and insecticides and agrochemicals. 16,17 To address the need for tools that can offer molecular-level insight into processes such as chiral symmetry breaking and phase amplification, we previously developed a generic molecular model for studying chirality phenomena inspired by hydrogen peroxide, 18,19 the simplest chiral molecule; note, however, that this model system uses molecular parameters as tunable variables to explore the range of behaviors compatible with this type of chirality rather than as fitting parameters aimed at reproducing the properties of hydrogen peroxide or any other specific molecule. The chiral molecules consist of four sites, with chirality encoded in each molecule's dihedral angle; that is, bond constants are specified such that the tetrameric molecules can exist in either left-handed L-or righthanded D-configurations (see Figure 1).…”