Elson Santiago Alvarenga

BACKGROUND: Motivated by the growing demand for increased food production and the need to identify new, more selective and effective herbicides in view of the resistance developed by plants to traditional herbicides, we synthesized six novel tetronamides derived from mucobromic acid and menthol. The structures of these compounds were characterized by spectroscopic techniques, complemented by theoretical calculations based on Density Functional Theory (DFT). In addition, we evaluated the phytotoxic activity of these substances in species such as Cucumis sativus , Solanum lycopersicum , Sorghum bicolor L. Moench, Urochloa brizantha and Bidens pilosa . RESULTS: The acyclic form of mucobromic acid was activated by (1 S )‐(+)‐10‐camphorsulfonic acid (CSA) for the enantioselective synthesis of compound 1b, which served as a starting point for the aza‐Michael addition/elimination reaction on the butenolide ring. In this reaction, the carbon at the C4 position was activated, allowing the nucleophilic attack by different substituted anilines, giving rise to the new tetronamides 2b‐7b. The relative configuration of the chiral centers of these substances was defined as SRSR based on spectroscopic analysis, theoretical calculations and the probabilistic methods DP4, DP4+, Linear Regression (R ² ), and Corrected Mean Absolute Error (CMAE). The bioassays performed indicated significant inhibition of the growth of roots and shoots of U . brizantha . CONCLUSION: These results confirm the potential of these tetronamides as selective phytotoxic agents and pave the way for the future development of more effective and sustainable herbicides, contributing to intelligent weed management and increased agricultural productivity. © 2026 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

The increasing demand for food is the driving force behind the search for novel, more selective, and less hazardous agrochemicals. Natural products are gaining prominence recently due to the promise of being green agrochemicals, but many natural products are poorly soluble in water, which reduces their applicability. In this work, we successfully formulated a water-insoluble Saussurea lappa root extract into a stable aqueous suspension using xanthan gum. The colloidal suspension was characterized by rheology, dynamic light scattering, and zeta potential. The results demonstrated that the suspension is a stable, sprayable, shear-thinning viscoelastic system (weak gel). A series of S. lappa solutions with xanthan gum were prepared and tested against five plant species, observing the inhibitory effect on the shoots and roots. The results were also compared with the commercial herbicide Dual. The S. lappa extract presented results comparable to or even greater than Dual for Lactuca sativa, Cucumis sativus, Brachiaria decumbens, and Bidens pilosa. However, it showed low inhibitory activity for Sorghum bicolor, highlighting its potential for selective weed control. This work illustrates xanthan gum as an effective vehicle for formulating insoluble natural products and demonstrates that S. lappa extract is a promising candidate for developing novel herbicides.

BACKGROUND: Due to the growing resistance of weeds to known herbicides, the search for new bioactive substances has been increasing in recent years. Imides belong to an important class of chemical compounds known to present various biological activities such as herbicide, fungicide, insecticide, and bactericide. In this study, the synthesis, purification, structural elucidation, and bioassays of four pairs of epoxy tetrahydrophthalimides 15a – 18a and 15b – 18b were conducted. Additionally in silico studies were performed to identify potential biological targets for the synthesized compounds. RESULTS: The target compounds were prepared using a four‐step synthetic route that starts with a microwave‐assisted Diels–Alder reaction between maleic anhydride and isoprene. All synthesized compounds had their phytotoxicity evaluated using germination tests in Petri dishes against Lactuca sativa , Cucumis sativus , Sorghum bicolor and Bidens pilosa . At concentrations of 500 and 300 μ m substance 16a presented inhibition of 70% and 66%, respectively, of the aerial parts of sorghum plants, which is higher than that observed for the commercial herbicide S ‐metolachlor. Molecular docking studies were performed for compounds 15a , 15b , 17a , and 17b , indicating that they form complexes with the mitogen‐activated protein kinase 5R92, which shares similar amino acid sequences with those found in plants. CONCLUSION: All substances caused inhibition or stimulation of seed growth compared to the control. Some substances caused plant growth inhibition superior or equivalent to the commercial herbicide, denoting these imides for the development of new agrochemicals. In silico studies suggest that mitogen‐activated protein kinase may be the target of these compounds. © 2025 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Chemical control is key to minimizing agricultural losses, driving the search for more efficient and selective herbicides. This study reports the synthesis of epoxyoxirenes, their phytotoxic evaluation, and an in silico analysis to identify the protein target of the most active compound in plants. Compounds 2–19 were tested on Lactuca sativa spp., Allium cepa spp., Cucumis sativus spp., Triticum aestivum, and Bidens pilosa. The synthetic route began with anhydride 1, obtained via a Diels–Alder reaction between maleic anhydride and furan (91% yield). Anhydride 1 was converted into amides 2–7 through reactions with aromatic amines (>92% yields), followed by cyclization to imides 8–13 (60–83% yields), and subsequent epoxidation to afford epoxides 14–19 (62–98% yields). All the compounds interfered with seedling development, with compounds 2–7 showing the greatest phytotoxicity to B. pilosa at concentrations of 500 μM and 1000 μM. An in silico analysis suggested plant tubulin as a potential protein target for the most active compounds. These findings highlight epoxyoxirenes as promising scaffolds for novel herbicide development and support further investigation into their mechanism of action.

Considering the resistance of weeds to different herbicides with different mechanisms of action, the search for new, more selective compounds with low toxicity to other species in nature has been very important for the development of agriculture. Because of that, considering the biological activity of allelochemicals and natural epoxides, four new epoxy compounds derived from dehydrocostus lactone were synthetized and evaluated for their potential herbicide activity against three species of seeds, Allium cepa (onion), Lepidium sativum (garden cress), and Lactuca sativa (lettuce). In assays with A. cepa, compound 4 inhibited radicle length by 80% at 100 μM. Notably, for L. sativum, compound 4 showed significant inhibition, reducing stalk and radicle lengths by 80% at 100 μM, surpassing the performance of the commercial herbicide Logran. However, diol 5 notably inhibited radicle growth by 28% at 100 μM, making the most significant observed effect. One of the noteworthy lactones studied is epoxide 4. This highlights the importance of the epoxide functional group in affecting both radicle and shoot lengths of seeds. Therefore, the synthesis of these compounds has proven advantageous and holds great potential for the development of new herbicides.

Aim: This study aimed to enhance the aqueous dissolution of SRPK inhibitor N-(2-(piperidin-1-yl)-5-(trifluoromethyl)phenyl)isonicotinamide (SRPIN340). Materials & Methods: A complex with p-sulfonic calix[6]arene (Host) and SRPIN340 (Guest) was prepared, studied via H-1 nuclear magnetic resonance (NMR) and theoretical calculations and biologically evaluated on cancer cell lines. Results & conclusion: The 1:1 host (H)/guest (G) complex significantly enhanced the aqueous dissolution of SRPIN340, achieving 64.8% water solubility as determined by H-1 NMR quantification analysis. The H/G complex reduced cell viability by 75% for HL60, similar to 50% for Nalm6 and Jurkat, and similar to 30% for B16F10 cells. It exhibited greater cytotoxicity than free SRPIN340 against Jurkat and B16F10 cells. Theoretical studies indicated hydrogen bond stabilization of the complex, suggesting broader applicability of SRPIN340 across diverse biological systems. {GRAPHICAL ABSTRACT}

Sesquiterpene lactones (SL) represent a class of secondary metabolites found in the Asteraceae family, notable for their unique structures. The SL α‐santonin (1) and its derivatives are worthy of mention due to their diverse biological properties. Additionally, 4H‐chromenes and 4H‐chromones are appealing frameworks holding the capability to be used as structural motifs for new drugs. Furthermore, unambiguous structural elucidation is crucial for developing novel compounds for diverse applications. In this context, it is common to find in the literature molecules erroneously assigned. Therefore, the use of quantum mechanical calculations to simulate NMR chemical shifts has emerged as a valuable strategy. In this work, we conceived the synthesis of two halogenated 4H‐chromenediones derived from photosantonic acid (2), a photoproduct arising from irradiation of α‐santonin (1) in the ultraviolet region. The structure of the chlorinated and brominated products was determined by NMR analysis, with the aid of quantum mechanical calculations at the B3LYP/6‐311 + G(2d,p)//M062x/6‐31 + G(d,p) level of theory. All analyses were in agreement and led to the assignment of the brominated 4H‐chromene‐2,7‐dione as (3S,3aS,5aR,9bS)‐5a‐(2‐bromopropan‐2‐yl)‐3‐methyl‐3,3a,5,5a,8,9b‐hexahydro‐4H‐furo[2,3‐f]chromene‐2,7‐dione (11b) and of the chlorinated 4H‐chromene‐2,7‐dione as (3S,3aS,5aR,9bS)‐5a‐(2‐chloropropan‐2‐yl)‐3‐methyl‐3,3a,5,5a,8,9b‐hexahydro‐4H‐furo[2,3‐f]chromene‐2,7‐dione (12b). The diastereoselectivities of the reactions were explained based on products and intermediates formation energy calculated using B3LYP/6‐31 + G(d,p) as the level of theory. Structures 11b and 12b were identified as the thermodynamic and kinetic products of the reaction among all candidates. Consequently, the strategy utilized in this study is robust and successfully illustrates the use of quantum mechanical calculations in the structural elucidation of new compounds with potential applications as novel drugs or products.