Synthesis and fungicidal activity of deuterated pefurazoate

Deuterium labeled agrochemicals have been widely used as probes in the metabolism and toxicology study or internal standards in the agrochemical residue analysis. Because of the primary deuterium kinetic isotope effect, the cleavage of C−D bonds requires higher activation energy than that of C−H bonds. Deuterium labelled agrochemicals may have longer half-lives and reduced toxicity to non-target organism. Pefurazoate has good control effect on rice bakanae disease and rice blast. In this study, four types of deuterated pefurazoate was synthesized using novel sodium dispersions mediated single electron transfer reductive deuterations developed by Jie An’s lab, and three of them were first reported in this work. Their fungicidal activities against Pyricularia oryzae and Gibberella fujikuroi were evaluated, which were comparable to that of the unlabeled pefurazoate. The deuterated pefurazoate can be used as the probe in the metabolism study, the toxicity study or as the MS internal standard in the residue analysis.