Description:
AbstractDeuterium labeling and high resolution mass spectroscopy have been used to determine the modes of electron impact fragmentation of 3,3‐dimethyl‐1‐methylthio‐2‐butanone O‐[(methylamino)carbonyl]oxime, thiofanox and its metabolites, the sulfoxide and sulfone. The mass spectra of the corresponding oximes were also examined. The carbamates fragmented chiefly by two competing pathways—the loss of CH3NCO or the sulfur‐containing moiety. The favored process was dependent on the oxidation state at sulfur. Several unusual rearrangements were noted.