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The commercial samples of the second-generation rodenticidal substance bromadiolone (I) have been studied by UV and IR spectroscopy, RP HPLC, and X-ray diffraction (XRD). Conditions for identification of the isomeric composition by RP HPLC were preliminarily selected, which made it possible to divide the samples into groups differing in the isomeric (cis-/trans-) composition of I in the range from 82 : 18 to 72 : 28 (to 64 : 36 in the products). Some aspects of sample preparation and the results of the analysis of various formulations/products containing I are presented. Two different crystalline phases, Ia and Ib, were isolated from the amorphous commercial substances and characterized by a complex of physicochemical methods (IR, XRD, DTA, PPM), and comparative efficiency data were obtained. The crystal structure of Ib was determined by XRD analysis. An attempt to isolate I from various solvent systems based on dimethyl sulfoxide led to crystallization of phases that are the products of destruction and rearrangement. Under production conditions, heating in this particular solvent gives highly concentrated forms (premixes) of I, which are used to prepare poisoned rodenticidal baits. An analysis of the XRD data showed that in addition to the expected salicylic acid, the rearrangement products were cyclic derivatives: triacetone triperoxide and γ-butyrolactone II with bulky substituents in the third and fifth positions. Direct synthesis of II is difficult because of the presence of bulky substituents, but can be achieved via direct rearrangement of I, as found in the course of the present work. Apparently, homologs of γ-butyrolactone with other substituents can be obtained using substances related to bromadiolone.
Кочетов et al. (Wed,) studied this question.