MIA-QSAR analysis of an increased data set of 1,3,4-oxa/thiadiazole nematicides to enhance the molecular diversity and agrochemical candidacy

Abstract

Tylenchulus semipenetrans nematodes affect citrus crops and may develop resistance to commercially available nematicides. In this sense, two series of 1,3,4-oxa- and thiadiazole compounds have been recently synthesised and tested as nematicides against T. semipenetrans, demonstrating promising results. We report herein a molecular modelling study that combines these two series of congeneric compounds to form a single and enhanced data set. The chemical structures of these compounds were correlated with the respective nematicidal activities (pLC50) using multivariate image analysis (MIA) descriptors in quantitative structure-activity relationship (QSAR) analysis. The partial least squares (PLS) regression yielded reliable and predictive models ( r 2 ≈ 0.85, q 2 ≈ 0.70, and r pred 2 ≈ 0.71). Therefore, novel 1,3,4-oxa- and thiadiazole derivatives were proposed and a few of them exhibited predicted nematicidal performance better than those of the parent compounds.