Synthesis and structure–activity relationships of quaternary ammonium cephalosporins with 3-pyrazolylpyridinium derivatives

Cephalosporins with 3-pyazolylpyridinium at C-3 position, which is supposed to exhibit synergic activity of ceftazidime and cefoselis, were synthesized and their antibacterial activity against Gram-positive and Gram-negative was inspected.