Synthesis of porphyrin-polyethylenimine conjugates as antimicrobial agent

BOARINI M.; PEREZ E.; GSPONER N.; MILANESIO M. E.

Basel

Congreso; The 25th International Electronic Conference on Synthetic Organic Chemistry (ECSOC25); 2021

Multidisciplinary Digital Publishing Institute (MDPI),

Increasing of resistant bacteria to clinical use antibiotics has conducted to establish new treatments for infections. One of them includes photodynamic inactivation of microorganisms. In general, the presence of positive charge precursor groups allows improve the photoinactivation due to an increase in interaction with microbial cells. In this context, 5,15-di(4-(N,N-dimethylaminophenyl)-10,20-di(pentafluorophenyl) porphyrin (1) and 5,10,15,20-tetrakis(pentafluorophenyl)porphyrin (2) were synthesized from the condensation of pentafluoro benzaldehyde and pyrrol catalysed by boron diethyl eterate in dichloromethane (DCM). After oxidation with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone and purification with flash chromatography. An aromatic nucleophilic substitution reaction was used to obtain conjugated polymers based in these porphyrins covalently linked to Polyethylenimine (PEI-1 and PEI-2). The reaction was carried out in N,N-dimethylformamide (DMF). After that, the solvent was removed by distillation under reduce pressure and the solid rest was washed with petroleum ether and drying in a vacuum oven. Sprectroscopic and photodynamic studies indicated that PEI-2 is more effective than PEI-1 to produce singlet oxygen and decompose L-tryptophan with a significant contribution of a type II mechanism. In addition, in vitro PDI studies demonstrated that both polymers are effective phototherapeutic agents for the eradication of bacteria.