Acid- and Base-Mediated Hydrolysis of Dichloroacetamide Herbicide Safeners
Monica E. McFadden, Eric V. Patterson, Keith P. Reber, Ian W. Gilbert, John D. Sivey, Gregory H. LeFevre, David M. Cwiertny
Abstract
), and under high-pH conditions representative of lime-soda softening, benoxacor's half-life was 13 h─a timescale consistent with partial transformation during water treatment. Based on Orbitrap LC-MS/MS analysis of dichloroacetamide hydrolysis product mixtures, we propose structures for major products and three distinct mechanistic pathways that depend on the system pH and compound structure. These include base-mediated amide cleavage, acid-mediated amide cleavage, and acid-mediated oxazolidine ring opening. Collectively, this work will help to identify systems in which hydrolysis contributes to the transformation of dichloroacetamides, while also highlighting important differences in the reactivity of dichloroacetamides and their active chloroacetamide co-formulants.