An integrated NMR and DFT study on the conformational preferences of N-alkyl benzamides.
VAIROLETTI, Franco; RODRÍGUEZ, Paulina; CANTERO, Jorge; PAULINO, Margot; FAILACHE, Natalia Alvarez; ELLENA, Javier; SALINAS, Gustavo; DOSSI, Gonzalo Hernández; MAHLER, Graciela; SAIZ, Cecilia.
VAIROLETTI, Franco; RODRÍGUEZ, Paulina; CANTERO, Jorge; PAULINO, Margot; FAILACHE, Natalia Alvarez; ELLENA, Javier; SALINAS, Gustavo; DOSSI, Gonzalo Hernández; MAHLER, Graciela; SAIZ, Cecilia.
Abstract: Recently introduced to the market, benzamides represent a new chemical family for combating plant-parasitic nematodes. This work describes the design, synthesis and structural characterization of novel N-alkyl benzamides and evaluates their efficacy as nematicides. The prepared compounds presented cis/trans isomerism in solution, as evidenced by 1H-NMR spectra in CDCl3 and DMSO-d6. Isomer assignment was achieved using a combination of experimental data and density functional theory (DFT) calculations, including 1H-NMR chemical shift predictions. For F-containing compounds, 19F-NMR predictions, conformational analysis and 1H-19F COSY experiments provided additional support. Among the studied compounds, terminal N-methyl cis isomers displayed higher 1H-NMR chemical shifts than the corresponding trans isomers, whereas 13C-NMR signals presented higher chemical shifts for the trans isomers compared to the cis ones. One of the compound's structures was further characterized in the solid state. Pyridine N-methylamide 7 yielded suitable crystals for X-ray diffraction of the trans isomer. The intermolecular interactions observed included non-classical C-H···O and C-H···F hydrogen bonds as well as a 4% contribution of Cl···F interactions. Infrared spectrum for 7 was analyzed and signals assigned with the aid of computational tools. All compounds were assayed against Caenorhabditis elegans. Among the N-alkylated benzamides, N-methyl-thioamide 10 showed the highest motility inhibition (56 ± 4% at 10 µM).
@article={003306053,author = {VAIROLETTI, Franco; RODRÍGUEZ, Paulina; CANTERO, Jorge; PAULINO, Margot; FAILACHE, Natalia Alvarez; ELLENA, Javier; SALINAS, Gustavo; DOSSI, Gonzalo Hernández; MAHLER, Graciela; SAIZ, Cecilia.},title={An integrated NMR and DFT study on the conformational preferences of N-alkyl benzamides},journal={Journal of Molecular Structure},note={v. 1371, p. 146455-1-1-46455-11 + supplementary materials},year={2026}}