SYNTHESIS; SPECTROSCOPY AND ELECTROCHEMISTRY OF NEW 4-(4-ACETYL-5- SUBSTITUTED-4, 5-DIHYDRO-1, 3,4-OXADIAZOL-2-YL)METHOXY)-2H-CHROMEN-2-ONES AS A NOVEL CLASS OF POTENTIAL ANTIBACTERIAL AND ANTIOXIDANT DERIVATIVES

N. Hamdi, V. Passarelli and A. Romerosa


Heterocyclic and Organometallic Chemistry Laboratory, Borj Cedria Higher Institute of Sciences and Technology, Environment Touristic road of Soliman B.P. 95. 2050 Hammam- Lif, Tunisia

Abstract:

The synthesis of the new 4-(4-acetyl-5- substituted -4, 5-dihydro-1, 3,4-oxadiazol-2-yl)methoxy)-2H-chromen-2-ones derivatives 5 was accomplished by the using of 4- hydroxycoumarine as a starting material. The structures of the obtained compounds have been characterized by UV, IR, ¹H, ¹³C-NMR, NOESY and HMBC NMR spectra to elucidate the different positions of protons and carbons. All the compounds exhibited one quasireversible redox processes. The UV absorption spectra of the obtained compounds showed strong absorption bands between 264 and 291 nm assigned to π-π * transitions of the oxadiazole group. All the newly synthesized compounds were screened for their antibacterial and antioxidant activities. Antimicrobial studies revealed that compounds 5a and 5b showed significant antibacterial activity against Escherichia coli and Pseudomonas aeruginosa 27853. Furthermore these compounds showed antioxidant activities of different extents with respect to individual compounds as well as to the antioxidant methods. The compound 5e was found to be the most active antioxidant in the series which makes the investigated complexes promising a new class of antibacterial compounds.

Keywords: 4-hydroxycoumarin. 1, 3,4-Oxadiazoles, carbohydrazide, antibacterial activity, Antioxydant activity.