Uses
Flocoumafen is a second generation anticoagulant rodenticide. Flocoumafen is extremely effective against strains of pest rodents resistant to conventional anticoagulants. Flocoumafen is highly toxic and is used strictly in sewers and indoors in some places such as UK.
Description
Flocoumafen is a coumarin rodenticide defined as a second-generation indirect anticoagulant. It has a low aqueous solubility and a low volatility. Evidence suggests it is persistent in both soil and water systems. Based on physico-chemical properties, there is some risk that the substance may to leach to groundwater. It is moderately toxic to birds and aquatic invertebrates but highly toxic to fish. It has a high mammalian oral toxicity.
Definition
ChEBI: Flocoumafen is a ring assembly, a member of naphthalenes and a member of benzenes.
Production Methods
Flocoumafen is commercially synthesised through a multi-step process involving the construction of its complex coumarin-based structure. The synthesis begins with inexpensive starting materials such as anisole and phenylacetyl chloride, which are sequentially transformed into key intermediates including 4-methoxyphenylacetophenone and 3-(4-methoxyphenyl)-1-tetralone. These intermediates undergo further reactions to form a tetrahydronaphthalene core, which is then coupled with a chromen-4-one moiety to yield the coumarin scaffold. A final etherification step introduces the trifluoromethylbenzyloxy group, completing the flocoumafen molecule.
Mechanism of action
Flocoumafen is a second generation anticoagulant rodenticide that disrupts the vitamin K cycle, which is essential for the synthesis of blood clotting factors. It acts as a potent antagonist of the enzyme Vitamin K1 epoxide reductase (VKOR), leading to a blockage in the recycling process of Vitamin K.
in vivo
Flocoumafen (0.02-0.1 mg/kg, once a week for 14 weeks) accumulates residues in the liver of rats and cannot be completely metabolized, showing anticoagulant toxicity at high doses[3].
| Animal Model: | Male Fischer rats[3] |
| Dosage: | 0.02 and 0.1 mg/kg; once a week; for 14 weeks |
| Administration: | Oral |
| Result: | Caused noticeable cell accumulation in the liver, with residuals increasing as the dose rises at low doses, while at high doses, it stabilized after a while. The lethal anticoagulant effected only occurs when the binding sites were saturated.
Showed about 30% of the cumulative dosage disappeared from the feces within 3 days after each administration at low doses,for high doses, this value ranges from 18% after the first dose to 59% after the tenth dose, and anticoagulant toxicity appeared after six weeks.
|
IC 50
MMP-9; Glucocorticoid Receptor 2
Metabolic pathway
Flocoumafen exists as cis and trans isomers (Scheme 1). The tetralin ring
adopts its most stable conformation in each case and the two forms have
very similar shapes. Both are active rodenticides. The fate of flocoumafen
in soils and plants has not been studied in detail because the compound is
usually used as a pelleted bait or in a wax block. This limits its dissipation
in the environment. Studies in animals and birds have been conducted
as part of the assessment of safety and to investigate mode of action.
Metabolism is slow in the rat and rapid in Japanese quail but this difference
should be interpreted with care because of the 100-fold difference
in dose used (see also Overview).
Degradation
Flocoumafen is a stable compound; no detectable degradation occurs at
50 °C at pH 7-9 over 4 weeks.
Pesticide Type
Rodenticide
