Fish Toxicity and Dealkylation of Aromatic Phosphorothionates ‐ QSAR∗

Quantitative structure‐activity relationships.

Analysis Using NMR Chemical Shifts Calculated by the IGLO Method

Abstract

Literature data on the alkylation reactivity and acute fish toxicity of nine O,O‐dimethyl O‐phenyl phosphorothionates are subjected to regression analyses using calculated physicochemical properties of the compounds. Thereby, site‐specific reactivities are quantified by individual gauge for localized molecular orbitals (IGLO) calculations of nuclear magnetic resonance (NMR) shifts for all nuclei of the molecules. The results show that the alkylation rates have a close relationship to the ¹⁷O NMR shifts of the oxygen at the reaction site, whereas the toxicity variation can be described by a linear two‐variable equation based on the octanol/water partition coefficient and the ¹⁷O NMR shift of the phenolic oxygen. The present approach has both an interpretative and predictive value and is expected to be applicable for related quantitative structure‐activity relationships (QSAR) studies on similar classes of insecticides.

Notes

Quantitative structure‐activity relationships.

Present address: Umweltforschungszentrum Leipzig‐Halle GmbH, Permoseretraβe 15, D‐O‐7050 Leipzig, FRG.