Synthesis of Bodipy-tagged galactoconjugates and evaluation of their antibacterial properties

As a development of our research on biocompatible glycoconjugate probes, and specifically multi-chromophoric systems, herein we report the synthesis and early bactericidal tests of the two luminescent glycoconjugates whose basic structure is characterized by two boron dipyrromethene difluoride (BODIPY) moieties and three galactoside rings mounted on an oligophenylene ethynylene (OPE) skeleton. BODIPY fluorophores have found in the last decades large application in many branches of biology. In particular, molecular platforms showing two different BODIPY groups, have unique photophysical behaviour useful in fluorescence imaging. The construction of the complex architecture of the new probes is accomplished through a convergent route that exploits a series of copper-free Heck-Cassar-Sonogashira cross-couplings. The great emergency due to the proliferation of bacterial infections in conjunction with the growing antibiotic resistance requires the production of new multifunctional drugs and efficient ways for their targeted delivery to control bacterial-associated diseases. Preliminary studies of the glycoconjugate properties as antibacterial agents against representatives of Gram-negative (P. aeruginosa) and Gram-positive (S. aureus) pathogens, associated with chronic infections, indicated a significant bactericidal activity ascribable to their structural features.