Synthesis, Anti-Bacterial and Anti-Oxidant Activity of Azo-Oxazolone and Their Ring Opening Azo-Benzamide Derivatives

This article describes the controlled synthesis and characterization of azo oxazolone scaffold compounds containing multifunctional groups such as carbonyl group, imine and carbon-carbon double bond. The reaction of the azo-oxazolone with aromatic amines led to the ring-opening of the azo-oxazolone into the corresponding azo-benzamide derivatives in a short time (average 10 min), resulting in high yield (>90%). All newly synthesized compounds were characterized by the common spectral analysis such as UV, IR, ¹H-NMR, ¹³CNMR, Elemental analysis and MS spectrometry.

Objective: The aim of the study was to synthesize new bioactive azo-benzamides by using azo-oxazolone as a synthon utilizing its ring-opening function.

Materials and methods: Azo-benzamide derivatives were prepared in very good yield via ring-opening reaction of azo-oxazolone with aromatic amines in the presence of acetic acid under reflux for few minutes.

Results and discussion: Chemical structures of the newly synthesized compounds were characterized by UV, IR, ¹H-NMR, ¹³C-NMR, Elemental analysis and MS spectrometry.

Conclusion: The new azo-oxazolone 4 and azo-benzamide compounds 5a, 5c, 5f, 5h, 5j were screened against Escherichia coli as G(-ve) and Staphylococcus aureus as G(+ve) using ciprofloxacin as a standard. All compounds showed high inhibition potency against E-Coli but low inhibition for S-aureus. Compounds 4, 5c, and 5J showed more reactivity against E-coli. Others: Also, the compounds were tested for their anti-oxidant activity by both DPPH and FRAP methods. The results showed that some compounds possessed moderate anti-oxidant activity in comparison to ascorbic acid as control, typically the compounds bearing OCH₃ and OCH₂CH₃ groups.