Flupyradifurone (Sivanto™) and its novel butenolide pharmacophore: Structural considerations

Flupyradifurone (4-[(2,2-difluoroethyl)amino]-2(5H)-furanone), a member of the new class of butenolide insecticides, contains a novel bioactive scaffold as pharmacophore. It is very versatile in terms of application methods to a variety of crops, exhibits excellent and fast action against a broad spectrum of sucking pest insects including selected neonicotinoid resistant pest populations such as whiteflies and aphids expressing metabolic resistance mechanisms. As a partial agonist flupyradifurone reversibly binds to insect nicotinic acetylcholine receptors (nAChRs) and lacks metabolization by CYP6CM1, a cytochrome P450 over-expressed in cotton whiteflies resistant to imidacloprid and pymetrozine. The butenolide insecticides exhibit structure-activity relationships (SAR) that are different from other nAChR agonists such as the classes of neonicotinoids and sulfoximines. The paper briefly reviews the discovery of the butenolide insecticide flupyradifurone, its SAR differentiating it from established nAChR agonists and a molecular docking approach using the binding site model of CYP6CM1vQ of Bemisia tabaci known to confer metabolic resistance to neonicotinoid insecticides.