Synthesis, Properties, and Structure of Ferrocenoylpyrazoles

The reaction of 3,5-disubstituted pyrazoles with ferrocenylvinyl ketone 1 produced new ferrocenoylpyrazoles 3a–3e. The reaction of 1 with unsymmetrical 3(5)-methyl-5(3)-trifluoromethylpyrazole gave both isomers, with their ratio depending on the reaction conditions. Both isomers 3d and 3e were isolated in pure form and characterized by mass spectrometry, NMR spectroscopy, and cyclic voltammetry. The structure of isomer 3e, which is the product of thermodynamic control, was confirmed by X-ray diffraction analysis (CCDC no. 2450072).