Synthesis of a new serie of quinoline-carboxamides based on methylated aminoesters: NMR characterization and antimicrobial activity

Abstract

Ten new quinoline-carboxamides have been synthesized using the coupling reaction between 2-oxo-1,2-dihydroquinoline-4-carboxylic acid as a substrate and five different amino ester at room temperature with basic media (triethylamine). The products were obtained with a good yield ranging from 60 to 80 % and were structurally characterized by 1H and 13C NMR spectroscopy and mass spectrometry. The antibacterial activities of the synthesized compounds have been evaluated against 9 strains of bacteria and compared to references (erythromycin, ofloxacin, ticarcillin, oxacillin, ampicillin, norfloxacin, ceftazidim, cefotaxim). The results showed that the majority of carboxamides-quinoline ester groups present a larger inhibition diameters than those of the antibiotics references. The highest antibacterial activity in vitro against the Enterococcus feacalis has been revealed for compound 1a (methyl 2-oxo-1.2-dihydroquinoline-4-yl-L-alaninate).