Synthesis of spirooxindolocarbamates based on Betti reaction: antibacterial, antifungal and antioxidant activities.

A series of new spirooxindolocarbamates 4a-l and 6a-d were synthesized by using the Betti reaction. All the target compounds were well characterized by IR, NMR and mass spectrometry. The structures of the compounds 4a and 4e were confirmed by the single crystal X-ray diffraction. The in vitro antibacterial activity results revealed that the compounds 4f exhibited excellent antibacterial activity against E. coli with MIC value 7.5 µg/mL when compared with the standard drug ciprofloxacin with MIC value 9.25 µg/mL. The compounds 4l and 6c exhibit significant inhibiting activity against E. Coli with MIC values 10.5 µg/mL and 9.5 µg/mL, respectively. The compounds 4c and 4e showed significant activity against S. aureus with MIC value 10.5 µg/mL. The compounds 4a and 4f were exhibited moderate antifungal activity against A. niger with MIC values 17.5 µg/mL and 18.0 µg/mL, respectively. The compounds 4f and 4l exhibited the potent antioxidant activity with IC50 values 9.12 ± 0.01 µM and 7.06 ± 0.78 µM, respectively.