Metabolism of the fungicide, ethaboxam, in confined rotational crops of sorghum, wheat, radish and lettuce was investigated using test substances labeled separately with 14C in the thiazole ring and near the thiophene ring. Radiolabeled residue was taken up from soil by the crops and metabolized into a number of compounds, two of which exceeded 10% of total radioactive residue (=0.05 ppm) in a few crop samples of the earliest planting interval (30 days after treatment). One of the metabolites was isolated from a combination of sorghum, radish and lettuce samples, and was identified as 4-ethyl-2-(ethylamino)-4-hydroxy-1,3-oxazol-5(4H)-one (EEHO). The other metabolite was isolated from radish and lettuce samples, and was identified as 4-ethyl-2-(ethylamino)-1,3-oxazol-5(4H)-one (EEO). Structure elucidation of EEHO and EEO was based on accurate mass measurement with high resolution QTOF mass spectrometry, and NMR spectroscopy using 2D COSY, spin decoupling and spin simulation experiments.   The parent ethaboxam was generally not present in the rotational crops except in trace quantity. The radiocarbons from both positions were incorporated into primary metabolites such as sugars, and remained distributed and bound to various structural constituents of the plants.

Transformation of <sup>14</sup>C-ethaboxam in confined rotational crops: Structures of two novel metabolites

248th National Meeting (2014)

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Transformation of 14C-ethaboxam in confined rotational crops: Structures of two novel metabolites

Transformation of ¹⁴C-ethaboxam in confined rotational crops: Structures of two novel metabolites