The title 1,3-diselenole Wittig reagent 9 has been synthesised by a new, efficient route from readily-available starting materials and reacted with a variety of functionalized aldehydes to form the corresponding 2-ylidene-1,3-diselenones 12 in respectable yields. X-ray analysis of a nitrosated derivative 14e, prepared by the reaction of 12e with isoamyl nitrite, has provided the first direct evidence for the stabilization of such systems by intramolecular oxygen-selenium interactions.
A new series of amino acid derivatives of quinolines was synthesized through the hydrolysis of amino acid methyl esters of quinoline carboxamides with alkali hydroxide. The compounds were purified on silica gel by column chromatography and further characterized by TLC, NMR and ESI-TOF mass spectrometry. All compounds were screened for in vitro antimicrobial activity against different bacterial strains using the microdilution method. Most of the synthesized amino acid-quinolines show more potent or equipotent inhibitory action against the tested bacteria than their correspond esters. In addition, many of them exhibit fluorescent properties and could possibly be utilized as fluorophores. Molecular docking and simulation studies of the compounds at putative bacterial target enzymes suggest that the antimicrobial potency of these synthesized analogues could be due to enzyme inhibition via their favorable binding at the fluoroquinolone binding site at the GyrA subunit of DNA gyrase and/or the ParC subunit of topoisomerase-IV.
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).
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