Identification of the Second Generation Rodenticidal Substance Bromadiolone (Analytical Determination, Structural Features and Rearrangement)

Industrial samples of the second-generation rodenticidal substance Bromadiolone (I) have been studied by UV, IR spectroscopy, RP HPLC and X-ray diffraction. The conditions for the identification of the isomeric composition by the RP HPLC method were preliminarily selected, which made it possible to divide the studied samples of the substance into groups differing in isomeric (cis/trans) composition I in the range from 82:18 to 72:28 (in products up to 64:36). The aspects of sample preparation and the results of the analysis of various formulations/products containing I are presented. Two different crystalline phases I and I have been isolated from amorphous technical substances, characterized by a complex of physico-chemical methods (IR, XRD, DTA, PPM) and comparative efficacy data have been obtained. The crystal structure for I was determined by the pX-ray diffraction analysis method. An attempt to isolate I from various solvosystems based on dimethyl sulfoxide led to the crystallization of phases representing degradation and rearrangement products. Under production conditions, when heated in this particular solvent, highly concentrated forms (premixes) I are obtained, which are used to prepare poisoned rodenticidal baits. Analysis of the XRD data showed that the rearrangement products, in addition to the expected salicylic acid, were cyclic derivatives: triacetone triperoxide and γ-butyrolactone II with volume substituents in the 3rd and 5th positions. Direct synthesis of II, due to the presence of bulky substituents, is difficult, however, as it turned out in the course of the work, it can be realized by directed rearrangement of I. Apparently, homologues of γ-butyrolactone with other substituents can be obtained using substances related to bromadiolone.