Synthesis, spectroscopy and electrochemistry of new 4-(4-acetyl-5- substituted-4, 5-dihydro-1, 3,4-oxodiazol-2-yl)methoxy)-2H-chromen-2-ones as a novel class of potential antibacterial and antioxidant derivatives

The synthesis of the new 4-(4-acetyl-5- substituted -4, 5-dihydro-1,3,4-oxodiazol-2-yl)methoxy)-2H-chromen-2-ones derivatives 5 was accomplished by the use of 4-hydroxycoumarine as a starting material. The structures of the compounds were confirmed by analytical 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 process. 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 compounds 5a-d was found to be the most active antioxidant in the series then Trolox, which makes the investigated complexes promising a new class of antibacterial compounds.