Microwave-assisted Quaternization of Various Pyridine Derivatives and their Antibacterial Activity

• Published in: Croatica Chemica Acta Vol. 90; no. 3; p. 425
• Main Authors: Bušić, Valentina, Pavlović, Hrvoje, Roca, Sunčica, Vikić-Topić, Dražen, Gašo-Sokač, Dajana
• Format: Journal Article Paper
• Language: English
• Published: Croatica Chemica Acta 01.12.2017; Hrvatsko kemijsko društvo
• Subjects: antibacterial activity; Chemical properties; Chemical reactions; microwave synthesis; Microwaves; NMR; Observations; Pyridine; pyridine derivatives; quaternization
• DOI: 10.5562/cca2937
• ISSN: 0011-1643

In this study, reactions of quaternization under microwave heating of pyridine, [alpha]-picoline, pyridine-4-aldoxime, pyridine-2-aldoxime, nicotinamide, isonicotinamide and pyridoxal oxime with different electrophiles: 2-bromo-4'-nitroacetophenone, 2-amino-4-chloro-methylthiazole hydrochloride, methyl iodide, 1,3-diiodopropane and 1,3-dibromopropane are reported. The synthesis yield by microwave dielectric heating is improved and reaction time shortened compared to conventional heating. The structure of obtained molecules were analyzed and determined by 1D and 2D NMR spectroscopy methods, IR spectroscopy and mass spectrometry. The highest antibacterial activity against two Gram-positive and two Gram-negative bacteria strains has been found for 1-[2-(4-nitrophenyl)-2-oxoethyl]pyridinium bromide (2). Keywords: microwave synthesis, pyridine derivatives, antibacterial activity, NMR, quaternization.