Synthesis and antimicrobial activity of spiro-oxindole-chromene derivative compounds based curcuminoid and chalcone

Multicomponent reactions (MCRs) are an efficient strategy to synthesize various heterocyclic compounds in one pot, and a simple step by combining the reactants in the same flask. In this study, a series of spiro-oxindole substituted chromene rings were synthesized via Knoevenagel and Micheal addition reaction using curcuminoid and chalcone as precursors. The reaction was assisted by Nickel ferrite (NiFe₂O₄) nanocatalyst in ethanol solvent at 70°C. NiFe₂O₄ was synthesized by the co-precipitation method and characterized by FTIR, XRD, and SEM-EDX. The two spiro-oxindole-chromene derivatives synthesized with the NiFe₂O₄ nanocatalyst were characterized their functional group vibrations and molecular mass by FTIR and GCMS, respectively. Under conditions with the addition of 5% (w/w) catalyst, the yields of compound 1 and compound 2 were 95% and 90%. Only compound 2 responded to antibacterial activity test against gram-positive bacteria (Staphylococcus aureus and Bacillus subtilis).