Synthesis, insecticidal activity, and phytotoxicity of novel chiral amides

N-Phenylnorbornenesuccinimide derivatives, agricultural defensive, and enzymatic target selection

BACKGROUND

Faced with the need to develop new herbicides with modes of action different to those observed for existing agrochemicals, one of the most promising strategies employed by synthetic chemists involves the structural modification of molecules found in natural products. Molecules containing amides, imides, and epoxides as functional groups are prevalent in nature and find extensive application in synthesizing more intricate compounds due to their biological properties. In this context, this paper delineates the synthesis of N-phenylnorbornenesuccinimide derivatives, conducts biological assays, and carries out in silico investigation of the protein target associated with the most potent compound in plant organisms. The phytotoxic effects of the synthesized compounds (2-29) were evaluated on Allium cepa, Bidens pilosa, Cucumis sativus, Sorghum bicolor, and Solanum lycopersicum.

RESULTS

Reaction of endo-bicyclo[2.2.1]hept-5-ene-3a,7a-dicarboxylic anhydride (1) with aromatic amines led to the N-phenylnorbornenesuccinic acids (2-11) with yields ranging from 75% to 90%. Cyclization of compounds (2-11) in the presence of acetic anhydride and sodium acetate afforded N-phenylnorbornenesuccinimides (12-20) with yields varying from 65% to 89%. Those imides were then subjected to epoxidation reaction to afford N-phenylepoxynorbornanesuccimides (21-29) with yields from 60% to 90%. All compounds inhibited the growth of seedlings of the plants evaluated. Substance 23 was the most active against the plants tested, inhibiting 100% the growth of all species in all concentrations. Cyclophilin was found to be the enzymatic target of compound 23.

CONCLUSION

These findings suggest that derivatives of N-phenylnorbornenesuccinimide are promising compounds in the quest for more selective and stable agrochemicals. This perspective reinforces the significance of these derivatives as potential innovative herbicides and emphasizes the importance of further exploring their biological activity on weeds. © 2024 Society of Chemical Industry.

Crystal Prediction via Genetic Algorithms in a Model Chiral System

Chiral crystals and their constituent molecules play a prominent role in theories about the origin of biological homochirality and in drug discovery, design, and stability. Although the prediction and identification of stable chiral crystal structures is crucial for numerous technologies, including separation processes and polymorph selection and control, predictive ability is often complicated by a combination of many-body interactions and molecular complexity and handedness. In this work, we address these challenges by applying genetic algorithms to predict the ground-state crystal lattices formed by a chiral tetramer molecular model, which we have previously shown to exhibit complex fluid-phase behavior. Using this approach, we explore the relative stability and structures of the model's conglomerate and racemic crystals, and present a structural phase diagram for the stable Bravais crystal types in the zero-temperature limit.

Complexation and enantioselectivity of novel bridge-like uranyl- 2-((1Z,9Z)-9-(2-Hydroxyphenyl)-3,5,6,8-tetrahydrobenzo[h][1,4,7,10] dioxadiazacyclododecin-2-yl)-5-methoxyphenol with chiral organophosphorus pesticide enantiomers of R/S-malathions

Designing new uranyl complexes with enantioselectivity is of great significance for the identification and separation of enantiomers of chiral pesticides. In this paper, a new asymmetric rigid uranyl-2-((1Z,9Z)-9-(2-Hydroxyphenyl)-3,5,6,8-tetrahydrobenzo[h][1,4,7,10] dioxadiaza-cyclododecin-2-yl)-5-methoxyphenol(Uranyl-HTDM) was designed, we used Uranyl-HTDM as a receptor to selectively coordinate with the guests of the chiral organophosphorus pesticide R/S-malathions(R/S-MLTs) to explore the receptor's enatioselectivity recognition of the chiral guests of R/S-MLTs. Density functional theory (DFT) method was used to comprehensively study the complexation mode of the receptor with enantiomers. The results showed that the U of Uranyl-HTDM could coordinate with both the thiophosphoryl sulfur and carbonyl oxygens of R/S-MLTs in different environments, respectively. The thermodynamics calculations further indicated that the receptor could selectively recognize the thiophosphoryl sulfur and carbonyl oxygen atoms of R/S-malathions, and the complexation abilities of Uranyl-HTDM to the R/S-malathions under different solvents were not the same. The smaller the polarity of solvents, the stronger the complexation ability of Uranyl-HTDM with R-malathion, toluene was an ideal solvent with large △G change and enatioselectivity coefficient of 99.55%. The study provides useful references for the design of new uranyl-salophens and for the experimental study on the molecular recognition of chiral organophosphorus pesticides.

Effect of configuration-dependent multi-body forces on interconversion kinetics of a chiral tetramer model

We describe a reformulation of the four-site molecular model for chiral phenomena introduced by Latinwo et al. ["Molecular model for chirality phenomena," J. Chem. Phys. 145, 154503 (2016)]. The reformulation includes an additional eight-body force that arises from an explicit configuration-dependent term in the potential energy function, resulting in a coarse-grained energy-conserving force field for molecular dynamics simulations of chirality phenomena. In this model, the coarse-grained interaction energy between two tetramers depends on their respective chiralities and is controlled by a parameter λ, where λ < 0 favors local configurations involving tetramers of opposite chirality and λ > 0 gives energetic preference to configurations involving tetramers of the same chirality. We compute the autocorrelation function for a quantitative chirality metric and demonstrate that the multi-body force modifies the interconversion kinetics such that λ ≠ 0 increases the effective barrier for enantiomer inversion. Our simulations reveal that for λ > 0 and temperatures below a sharply defined threshold value, this effect is dramatic, giving rise to spontaneous chiral symmetry breaking and locking molecules into their chiral identity.

Acaricidal Activity of Annonaceae Plants for Dermanyssus gallinae (Acari: Dermanyssidae) and Metabolomic Profile by HPLC-MS/MS

The poultry red mite Dermanyssus gallinae (De Geer) is the most important haematophagous ectoparasite in the poultry industry. The use of synthetic acaricides for this control is presenting risks related to human food. In this sense, plant secondary metabolites are promising for controlling this pest. Thus, this study aimed to evaluate the acaricidal activity of Duguetia lanceolata A.St.-Hil. (stem bark), Xylopia emarginata Mart. (stem bark), and Xylopia sericea A.St.-Hil. (stem bark and fruits) against D. gallinae. Additionally, the secondary metabolite profile of the X. emarginata was analysed by UFLC-DAD-ESI(+)-MS/MS (micrOTOF-QII) and data analysis was performed using the Molecular Networking. In a topical application test, all plant species tested showed bioactivity, in that order of toxicity with the respective probability survival: X. emarginata (stem bark) (0.28) > X. sericea (stem barks) (0.35) > X. sericea (fruits) and D. lanceolata (stem bark) (0.47). The most promising results were found for X. emarginata (LC₅₀ = 331.769 μg/cm²). It is noteworthy that the LC₅₀ of the insecticide cypermethrin was 1234.4 μg/cm², which was 73% higher than that of X. emarginata. The metabolomic profile of X. emarginata revealed the presence of alkaloids, amides, terpenoids, and phenolic compounds. This is the first report of X. emarginata acaricidal activity against D. gallinae and exploratory chemical analysis by untargeted metabolomics and the molecular network of this plant.

Efficacy of Seven Commercial Household Aerosol Insecticides and Formulation-Dependent Toxicity Against Asian Tiger Mosquito (Diptera: Culicidae)

For the indoor and outdoor pest controls, various types of insecticide formulations are available including aerosols, sprays, electric vaporizers, mosquito coils, and traps. In the present study, the insecticidal activity of aerosols, the most commonly used formulation of household insecticides for mosquito control, against Aedes albopictus (Skuse) was assessed using seven commercial products and some attributes which can affect the efficacy of aerosol were investigated as well. The products had difference in their chemical composition of active ingredients, propellant/liquid phase ratios, solvent types, and nozzle orifice sizes, and these characteristics seem to affect the overall insecticidal activity. In general, solvent type dominantly determined the insecticidal activity, where four products in oil-based solvent system showed greater mortality (97.5% in average) than water-based aerosols (38.3% in average) against the mosquitoes located at the far side of the test chamber. The contribution of solvent type and nozzle orifice size were further examined with the sample aerosols, and the orifice size were determined more influential to the spray distance. Regardless of solvent types, the sample products attached to a bigger actuator (0.96 mm in diameter) showed greater knock-down activity (>98%) than the smaller ones (0.48 mm, 62.5% in average) to the back panel in the chamber. On the other hand, solvent system significantly affected the residual activity, as the oil-based and water-based aerosols showed 2.3- and 4.8-fold decrease in KT50 values, respectively, between 1 and 10 min after the spray.

A bioactivity-oriented modification strategy for SDH inhibitors with superior activity against fungal strains

In this work, a total of 36 novel 5-(nicotinamido)-1-phenyl-1H-pyrazole-4-carboxylic acid derivatives were designed and synthesized successfully by introducing a carboxyl group based on the N-(1-(4-chlorophenyl)-4-cyano-1H-pyrazol-5-yl)-6-methoxynicotinamide. Among them, the growth inhibition assays on agar plates showed that compound 5IV-d(5-(2-chloronicotinamido)-1-(p-tolyl)-1H-pyrazole-4-carboxylic acid) exhibited the significant antifungal activity against four important fruit and main crop disease fungi (i.e., Valsa mali Miyabe et Yamada, Botryosphaeria dothidea, Helminthosporium maydis and Rhizoctonia cerealis) with EC₅₀ values of 22.6, 14.5, 17.6 and 18.2 μM, respectively. In addition, 5IV-d showed the excellent inhibitory effect against SDH enzymes with IC₅₀ values ranging from 9.4 to 15.6 μM. In vivo bioassay and molecular docking were applied to explore the potential in practical application and combination of modified structure and SDH. The results of structure-activity relationships indicates that the methoxy substitution at the benzene ring attached to the pyrazole ring and a wide variety of substituents could be responsible for the promising antifungal efficacy of the designed compounds. This study demonstrated that the compound 5IV-d can act as the most potent SDH inhibitor in the reported series of compounds.

Toxicity and Sublethal Effects of Phthalides Analogs to Rhyzopertha dominica

Phthalides and their precursors have demonstrated a large variety of biological activities. Eighteen phthalides were synthesized and tested on the stored grain pest Rhyzopertha dominica. In the screening bioassay, compounds rac-(2R,2aS,4R,4aS,6aR,6bS,7R)-7-bromohexahydro-2,4-methano-1,6-dioxacyclopenta[cd]pentalen-5(2H)-one (15) and rac-(3R,3aR,4R,7S,7aS)-3-(propan-2-yloxy)hexahydro-4,7-methano-2-benzofuran-1(3H)-one (17) showed mortality similar to the commercial insecticide, Bifenthrin® (≥90 %). The time (LT₅₀ ) and dose (LD₅₀ ) necessary to kill 50 % of the R. dominica population were determined for the most efficacious phthalides 15 and 17. Compound 15 presented the lowest LD₅₀ (1.97 μg g^-1 ), being four times more toxic than Bifenthrin® (LD₅₀ =9.11 μg g^-1 ). Both compounds presented an LT₅₀ value equal to 24 h. When applied at a sublethal dose, both phthalides (especially compound 15), reduced the emergence of the first progeny of R. dominica. These findings highlight the potential of phthalides 15 and 17 as precursors for the development of insecticides for R. dominica control.