Nano MgBi2O4: A Novel Green Catalyst for the One-step Cascade Condensation of Arylamines, Acetone and Isatins in Water

Nano-size MgBi2O4 has been synthesized for the first time via a simple co-precipitation method using the surfactant N-cetyl- N,N,N-trimethylammonium bromide (CTAB). Fourier transform infrared (FT-IR), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and X-ray powder diffraction (XRD) techniques were employed to characterize the nano-catalyst. Additionally, the reactivity of the prepared nanoparticles was investigated in the synthesis of 1 $^{\prime }$ -aryl-2 $^{\prime }$ -(2-oxoindolin-3-yl)spiro[indoline-3,5 $^{\prime }$ -pyrroline]-2,3 $^{\prime }$ -diones in a one-pot, one-step and pseudo four-component condensation of arylamine, acetone, and isatins at 50°C in water. Five new compounds were synthesized and identified. This procedure has various advantages such as, short reaction times, mild eco-friendly conditions and excellent yields to prepare a novel class of heteroaromatic compounds. MgBi2O4 possess superior qualities such as easy and economic preparation procedure and handling, stability, and non-toxicity. Its reusability has also been examined upto 4 runs without activity loss.