Synthesis and biological evaluation of dihydrotriazine derivatives as potential antibacterial agents

A series of 1,4-dihydro-1,3,5-triazine derivatives were designed and synthesized and their antibacterial and antifungal activities were evaluated. Most of the synthesized compounds showed potent inhibition of several Gram-positive bacterial strains (including multidrug-resistant clinical isolates) and Gramnegative bacterial strains, with minimum inhibitory concentrations (MICs) in the range of 2.1- 181.2 μmol/L. Compounds 7a and 7c presented the most potent inhibitory activities against Grampositive bacteria (e.g., Staphylococcus aureus 4220), Gram-negative bacteria (e.g., Escherichia coli 1924), and the fungus Candida albicans 7535, with MICs of 2.1 or 4.1 μmol/L. Especially, compound 7a was the most potent, with an MIC of 2.1 μmol/L against four multidrug-resistant, Gram-positive bacterial strains. The cytotoxic activity of the compound 7a, 7c and 7f was assessed in HepG2 cells, and the results suggest that 1,4-dihydro-1,3,5-triazine derivatives bearing a 6-benzyloxynaphthalen moiety are interesting scaffolds for the development of novel antibacterial agents.