Rodenticide, chemical structure

Anticoagulant rodenticides are also categorized by chemical structure. The chemical structure of the currently marketed products fits in one of two chemical classes 4-hydroxycoiunarins and indanediones. 

The formulas of some ARs are given in Figure 11.1, where it can be seen that they have some structural resemblance to both dicoumarol and vitamin K in its quinone form. All possess quinone rings linked to unsubstituted phenyl rings. The phenyl rings of the rodenticides confer hydrophobicity, especially in the relatively large and complex molecules of brodifacoum and flocoumafen. The chemical properties of some ARs are given in Table 11.1... 

In contrast, selective inhibition of enzyme activity involves highly specific interactions between the protein and chemical groups on the xenobiotic. An excellent example of this type of inhibition is seen in the toxic effect of fluoroacetate, which is used as a rodenticide. Although fluoroacetate is not directly toxic, it is metabolized to fluoroacetyl-CoA, which enters the citric acid cycle due to its structural similarity to acetyl-CoA (Scheme 3.5). Within the cycle, fluoroacetyl-CoA combines with oxalo-acetate to form fluorocitrate, which inhibits the next enzyme, aconitase, in the cycle [42]. The enzyme is unable to catalyze the dehydration to cis-aconitate, as a consequence of the stronger C-F bond compared with the C-H bond. Therefore, fluorocitrate acts as a pseudosubstrate, which blocks the citric acid cycle and, subsequently, impairs ATP synthesis. 

The Pesticide Index (ref. 14) lists the following categories of pesticides acaricides, attractants, chemosterilants, defoliants, fungicides, herbicides, insecticides, molluscicides, nematicides, plant regulators, repellents, and rodenticides. Listings are in alphabetical order with structural and molecular formulae for single chemical entities. Other data include CAS nomenclature and number Wiswesser Line Notation LD-50 and test animal data when available physical appearance and safety information. Also provided are a CAS nomenclature index separate molecular (line) formulae of chemicals identified by their common names a separate section of Wiswesser line notations, also with common names an appendix of manufacturers, and an appendix of recent publications dealing with pesticide names. 

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