Synthesis, characterization and crystal structures of boron-containing intermediates in the reductive amination of ferrocenecarboxaldehyde to a bis(ferrocenylmethyl) amine

Crystal structure and Hirshfeld surface analysis study of (E)-1-(4-chloro-phen-yl)-N-(4-ferrocenylphen-yl)methanimine

The substituted cyclo-penta-dienyl ring in the title mol-ecule, [Fe(C5H5)(C18H13ClN)], is nearly coplanar with the phenyl-1-(4-chloro-phen-yl)methanimine substituent, with dihedral angles between the planes of the phenyl-ene ring and the Cp and 4-(chloro-phen-yl)methanimine units of 7.87 (19) and 9.23 (10)°, respectively. The unsubstituted cyclo-penta-dienyl ring is rotationally disordered, the occupancy ratio for the two orientations refined to a 0.666 (7)/0.334 (7) ratio. In the crystal, the mol-ecules pack in 'bilayers' parallel to the ab plane with the ferrocenyl groups on the outer faces and the substituents directed towards the regions between them. The ferrocenyl groups are linked by C-H⋯π(ring) inter-actions. A Hirshfeld surface analysis of the crystal structure indicates that the most important contributions for the crystal packing are from H⋯H (46.1%), H⋯C/C⋯ H (35.4%) and H⋯Cl/Cl⋯H (13.8%) inter-actions. Thus C-H⋯π(ring) and van der Waals inter-actions are the dominant inter-actions in the crystal packing.

In vivo active organometallic-containing antimycotic agents

Fungal infections represent a global problem, notably for immunocompromised patients in hospital, COVID-19 patient wards and care home settings, and the ever-increasing emergence of multidrug resistant fungal strains is a sword of Damocles hanging over many healthcare systems. Azoles represent the mainstay of antifungal drugs, and their mode of action involves the binding mode of these molecules to the fungal lanosterol 14α-demethylase target enzyme. In this study, we have prepared and characterized four novel organometallic derivatives of the frontline antifungal drug fluconazole (1a-4a). Very importantly, enzyme inhibition and chemogenomic profiling demonstrated that lanosterol 14α-demethylase, as for fluconazole, was the main target of the most active compound of the series, (N-(ferrocenylmethyl)-2-(2,4-difluorophenyl)-2-hydroxy-N-methyl-3-(1H-1,2,4-triazol-1-yl)propan-1-aminium chloride, 2a). Transmission electron microscopy (TEM) studies suggested that 2a induced a loss in cell wall integrity as well as intracellular features ascribable to late apoptosis or necrosis. The impressive activity of 2a was further confirmed on clinical isolates, where antimycotic potency up to 400 times higher than fluconazole was observed. Also, 2a showed activity towards azole-resistant strains. This finding is very interesting since the primary target of 2a is the same as that of fluconazole, emphasizing the role played by the organometallic moiety. In vivo experiments in a mice model of Candida infections revealed that 2a reduced the fungal growth and dissemination but also ameliorated immunopathology, a finding suggesting that 2a is active in vivo with added activity on the host innate immune response.