Synthesis and Biological Activity of Silicon-Containing Ethylsulfonylpyridine Insecticides

Abstract

Ethylsulfonylpyridines are a novel chemical class of insecticides with excellent broad-spectrum activity and an unprecedented mode of action. With the objective of discovering novel ethylsulfonylpyridines with a broader spectrum, wider range of uses, and/or improved properties, we have started a research program aimed at introducing silicon motifs and studying their biological effects. We designed a series of Oxazosulfyl analogues where the hydrogen atom at the 5-position of the pyridyl moiety is replaced by a trialkylsilyl group and prepared these compounds applying denovo synthetic methodology. Our novel ethylsulfonylpyridines exhibit excellent insecticidal activities. The best compound, A18, resulting from our research exhibited an LC 50 value of 0.30 mg/L against Plutella xylostella and reached the activity level of the commercial standard Oxazosulfyl. Our findings confirmed our working hypothesis that at the 5-position of the pyridyl moiety larger groups with different hydrophobic, electronic, and steric properties are tolerated.

Design, Synthesis, and Biological Activity of Silicon-Containing Carboxamide Fungicides

“…Carbon–silicon bioisosteric replacement is a powerful research strategy to favorably modulate the potency, selectivity and bioavailability as well as the physicochemical and drug-like or pesticidal properties. − Silicon is the second most abundant element on Earth, easily available and possesses unique chemical properties allowing diverse, sometimes specific, chemical reactions due to its unique d -orbitals enabling coordination. , Moreover, silicon and silicon-containing groups are suited for classical C/Si switch strategies − and nonclassical replacement, like the replacement of some heteroatoms (O, N) and groups (amide, , vinyl , ). These replacements have proven to deliver surprising results that go beyond the expected additional benefit and offer a tool to explore unexpected effects for the evaluation of issues.…”