Synthesis of symmetrically substituted 3,3-dibenzyl-4-hydroxy-3,4-dihydro-1H-quinolin-2-ones, as novel quinoline derivatives with antibacterial activity.

A novel series of symmetrically substituted 3,3-dibenzyl-4-hydroxy-3,4-dihydro-1H-quinolin-2-ones was synthesized and tested as antimicrobials. The minimum inhibitory concentration (MIC) values of the most active heterocycles were slightly higher than those exhibited by levofloxacin, employed as comparator. Structural factors affecting the activity were explored along three diversification points, including the substituents of the aromatic rings of the 3-benzyl moieties, as well as the functionalization of both, the homocyclic ring of the heterocycle and the quinolonic nitrogen atom. 6-Chloro and 3,3-bis(4'-chlorobenzyl) derivatives showed the lower MIC values. Optimally substituted heterocycles were synthesized, which exhibited enhanced activity.