Green Synthesis and Antimicrobial/Antioxidant Screening of 4-[1-oxo-3-(substituted phenyl)-2-propenyl]-3-substituted Phenylsydnones

The present study reports the ultrasonic promoted synthesis and antimicrobial/antioxidant activity of a new series of 4-[1-oxo-3-(substituted aryl)-2-propenyl]-3-(substituted phenyl) syndromes. 4-[1-Oxo-3-(substituted aryl)-2-propenyl]-3-substituted phenyl sydnones (2a-i, 3a-i, 4a-i) are synthesized by ultrasonication method. The synthesis was carried out by reaction of 4-acetyl-3-(substituted phenyl) sydnones (1a-i) with various substituted aryl aldehydes (Ar-CHO). The structures of compounds were established by using NMR, IR, MS and elemental analysis. Compounds were evaluated for antibacterial, antifungal and antioxidant activity. Some of the synthesized compounds have shown good to moderate activity against gram negative bacteria whereas compounds 3c, 4c and 4f have shown marked activity against fungal strains. The compounds 2c, 3c, 4f have shown potent antioxidant activity as compared to reference standards. The compound 4f (IC₅₀ = 3.17 µM) is the most potent with methyl group as substituent showing good antioxidant activity even at very low concentrations. The ultrasonic method of synthesis was found to be simple, reduces reaction time and gives good yield when compared with traditional methods of synthesis. The results proved the necessity for further investigations to design molecules such as cyclization of sydnones with phenyl hydrazine, hydrazine and hydroxylamine for development of imminent potent antimicrobial, antioxidant and antitumor molecules.