[Quinolizidine derivatives with antibacterial activity]

Six quinolizidinyl-derivatives were tested for antibacterial actvity against a large number of gram-positive and gram-negative strains. 9-Lupinyliden-fluorene (I) and its epimer (II) at concentrations between 12,5 and 100 mg/l inhibit all gram-positive strains, while they are only weakly active against a few gram-negative bacteria. The tertiary alcohols (III) and (IV) are inactive against the gram-positive strains, while still exhibiting weak activity on the gram-negative. Compounds (V) and (VI) are completely inactive. The values of minimal bactericidal concentrations for compound (I) against the sensitive strains are equal to or no more than 4 times higher than values of MIC. It is interesting to note that compound (I) is able to give rise to cellular lysis at MIC.