Novel compounds, 1,3-selenazine derivatives, as antibacterial agents against Escherichia coli and Staphylococcus aureus.

The antibacterial activities of several kinds of novel 4H-5,6-dihydro-1,3-selenazine derivatives against Escherichia coli and Staphylococcus aureus were investigated. 4-Hydroxy-4-methyl-2-p-tolyl-4H-5,6-dihydro-1,3-selenazine (TS-1), 4-ethyl-4-hydroxy-2-p-tolyl-4H-5,6-dihydro-1,3-selenazine (TS-2), and 4-hydroxy-4-methyl-2-pentyl-4H-5,6-dihydro-1,3-selenazine (PS-1) exhibited strong inhibitory activity against E. coli, and TS-1, TS-2, PS-1, 4-hydroxy-4-methyl-2-pentyl-6-propyl-4H-5,6-dihydro-1,3-selenazine (PS-6) and 4-hydroxy-4-methyl-2-pentyl-6-phenyl-4H-5,6-dihydro-1,3-selenazine (PS-8) also showed inhibitory activity against S. aureus. 4H-5,6-dihydro-1,3-thiazines and 1,3-selenazole had no inhibitory activities against both bacteria. TS-1, TS-2, and PS-1 exhibited marked antibacterial activities against both Gram-negative and Gram-positive bacteria.