Synthesis and antimicrobial activity of carbonyl pyridoquinolones containing urea and piperazine residue

In the present work, carbonyl pyridoquinolones 8–33 were synthesized and their ability to inhibit gram positive stains Bacillus subtilis and Staphylococcus aureus, gram negative stains Escherichia coli and Pseudomonas aeruginosa, and fungi Candida albicans were studied. Carbonyl piperazines attached at C-3 position of pyridoquinolone exhibited good antibacterial activity when compared to standard drugs ciprofloxacin and gatifloxacin. Indeed carbonyl piperazine derivatives 24–32 when attached at C-3 position of pyridoquinolone increased the activity of their parent compound 6 than that of carbonyl ureas 8–23 exhibited lower antibacterial activity compared to carbonyl piperazine derivatives 24–32.