Synthesis and Antimicrobial Activity of New Mannich Bases with Piperazine Moiety.

A series of novel Mannich bases were designed, synthesized, and screened for their antimicrobial activity. The target compounds were synthesized from 4-(3-chlorophenyl)-5-(3-fluorophenyl)-2,4-dihydro-3-1,2,4-triazole-3-thione and different piperazine derivatives. The structures of the products were confirmed by H and C NMR and elemental analysis. The activity of piperazine derivatives against bacteria (Gram-positive: , , , , and ; Gram-negative: , , , and ) and yeasts (, , and ) was determined by the minimum inhibitory concentration and minimum bactericidal concentration values. Significant activity was observed against Gram-positive bacteria, mainly staphylococci (-) and bacteria of the genes of and (), as well as selected strains of Gram-negative bacteria, including bacteria of the family (), while all tested compounds showed high fungistatic activity against spp. yeasts, especially , with MICs ranging from 0.49 µg/mL () to 0.98 µg/mL () and 62.5 µg/mL (). In conclusion, the results obtained confirm the multidirectional antimicrobial activity of the newly synthesized piperazine derivatives. Furthermore, in silico studies suggest that the tested compounds are likely to have good oral bioavailability. The results obtained will provide valuable data for further research into this interesting group of compounds. The library of compounds obtained is still the subject of pharmacological research aimed at finding new interesting biologically active compounds.