Synthesis, Structural Characterization and Antibacterial Activity of Novel 7β-{[3-(substituted phenyl)-2-propenoyl]amino}-3-[(2,5-dihydro-6-hydroxy- 2-methyl)-5-oxo-cis-triazin-3-yl]-thiomethyl-cefalosporins

A series of 3-[(2,5-dihydro-6-hydroxy-2-methyl)-5-oxo-cis-triazin-3-yl]-thiomethyl-cefalosporins with various 3-phenyl-2-propenoyl substituted groups at the 7β-position were synthesized, structurally characterized and evaluated for antibacterial activity in vitro. To prepare these derivatives by the Vilsmeier's reagent method, it was necessary to carefully control the reaction conditions in order to avoid the formation of the biologically inactive α epimer. The NMR studies showed that the 3-phenyl-2-propenoyl moiety has little effect on chemical shifts of cephem nucleus protons and carbon atoms. Some of these cephalosporin derivatives showed good in vitro activity against methicillin sensible strains of Staphylococcus aureus (MSSA) and coagulase negative Staphylococcus (MSCoNS). Particularly effective were the compounds carrying a 3-(2'-chlorophenyl)-2-propenoyl or 2-methyl-3-phenyl-2-propenoyl moiety at 7β-position, both with an antibacterial potency close to cefazoline and higher than cefuroxime. All the synthesized cephalosporins were inactive against methicillin resistant strains of Staphylococcus aureus (MRSA) and coagulase negative Staphylococcus (MRCoNS).