Synthesis and antibacterial activity of 7β-2-(2-substituted aminothiazol- 4-yl)-(Z)-2- methoxyiminoacetylamido-3-quaternaryammoniummethyl- cephalosporins

In order to find new cephalosporin with more and more potent antibacterial activity, nine new fourth-generation cephalosporins (N₁-N₉) were synthesized from ethyl 2-(2-aminothiazol-4-yl)-(Z)-2-methoxyiminoacetate (1) via acylation, substitution, hydrolysis, active esterification, condensation and salt formation.  The structures of compounds (N₁-N₉) were confirmed by IR, MS, ¹H NMR and elemental analysis.  The target compounds possess different antimicrobial activities against Gram-positive and Gram-negative bacteria.  The preliminary results of antibacterial activities revealed that they showed better antibacterial activities against Gram-positive bacteria than cefpirome sulfate.  In particular, their activities against Staphylococcus aureus and Streptococcus albus are better.