Synthesis and Fungicide Activity on Asperisporium caricae of Glycerol Derivatives Bearing 1,2,3-Triazole Fragments.

In agriculture, the control of fungal infections is essential to improve crop quality and productivity. This study describes the preparation and fungicidal activity evaluation of 12 glycerol derivatives bearing 1,2,3-triazole fragments. The derivatives were prepared from glycerol in four steps. The key step corresponded to the Cu(I)-catalyzed alkyne-azide cycloaddition (CuAAC) click reaction between the azide 4-(azidomethyl)-2,2-dimethyl-1,3-dioxolane (3) and different terminal alkynes (57-91% yield). The compounds were characterized by infrared spectroscopy, nuclear magnetic resonance (1H and 13C), and high-resolution mass spectrometry. The in vitro assessment of the compounds on Asperisporium caricae, that is, the etiological agent of papaya black spot, at 750 mg L-1 showed that the glycerol derivatives significantly inhibited conidial germination with different degrees of efficacy. The most active compound 4-(3-chlorophenyl)-1-((2,2-dimethyl-1,3-dioxolan-4-yl) methyl)-1H-1,2,3-triazole (4c) presented a 91.92% inhibition. In vivo assays revealed that 4c reduced the final severity (70.7%) and area under the disease severity progress curve of black spots on papaya fruits 10 days after inoculation. The glycerol-bearing 1,2,3-triazole derivatives also present agrochemical-likeness properties. Our in silico study using molecular docking calculations show that all triazole derivatives bind favorably to the sterol 14α-demethylase (CYP51) active site at the same region of the substrate lanosterol (LAN) and fungicide propiconazole (PRO). Thus, the mechanism of action of the compounds 4a-4l may be the same as the fungicide PRO, blocking the entrance/approximation of the LAN into the CYP51 active site by steric effects. The reported results point to the fact that the glycerol derivatives may represent a scaffold to be explored for the development of new chemical agents to control papaya black spot.

Synthesis of novel glycerol-fluorinated triazole derivatives and evaluation of their phytotoxic and cytogenotoxic activities.

The control of weeds in agriculture is mainly conducted with the use of synthetic herbicides. However, environmental and human health concerns and increased resistance of weeds to existing herbicides have increased the pressure on researchers to find new active ingredients for weed control which present low toxicity to non-target organisms, are environmentally safe, and can be applied at low concentrations. It is herein described the synthesis of glycerol-fluorinated triazole derivatives and evaluation of their phytotoxic and cytogenotoxic activities. Starting from glycerol, ten fluorinated triazole derivatives were prepared in four steps. The assessment of them on Lactuca sativa revealed that they present effects on phytotoxic and cytogenotoxic parameters with different degrees of efficiency. The compounds 4a, 4b, 4d, 4e, 4i, and 4j have pre-emergent inhibition behavior, while all the investigated compounds showed post emergent effect. Mechanism of action as clastogenic, aneugenic, and epigenetic were observed in the lettuce root meristematic cells, with alterations as stick chromosome, bridge, delay, c-metaphase, and loss. It is believed that glycerol-fluorinated triazole derivatives possess a scaffold that can be explored towards the development of new chemicals for the control of weed species.

Identification of adjuvants in plant protection products applying a suspect screening workflow based on orthogonal techniques.

In this study, the identification of adjuvants (surfactants and solvents) in quizalofop-p-ethyl plant protection products (PPPs) was carried out by applying nuclear magnetic resonance (NMR), ultra-high-performance liquid chromatography (UHPLC) and gas chromatography (GC), both coupled to high-resolution mass spectrometry (HRMS), and using a suspect analysis approach. NMR provided a rapid and global overview of the composition of the studied samples and supported the tentative identification of the glycol ether family, commonly employed as surfactants, and 2-ethyl-1-butanol. UHPLC-HRMS was used for characterization of the glycol polymer surfactants, while GC-HRMS was used to obtain information about volatile organic compounds (benzene or naphthalene derivates) present in the PPPs. A total of nine adjuvants were characterized in the tested PPPs, belonging to naphthalene, benzene, sulphate and fatty acid esters of glycerol families. In addition, the estimation of compound concentrations was carried out using GC(LC)-HRMS, and finally, these concentration levels were related to their toxicity values.