Microwave-Assisted Synthesis of Spiro Heterocyclic Scaffolds Using Graphite Oxide as a Heterogeneous Carbocatalyst and Study of their Anti-Microbial Activities

Even though an astonishing variety of spirooxindole derivatives has been synthesized until now, the look for rapid, highly efficacious, environmental-friendly and more skilful methods is yet an ongoing challenge. Here, we present a microwave-assisted synthetic approach for the one-pot synthesis of spirooxindole-pyrimidine and spiro-chromeno indoline-trione derivatives in water using graphite oxide (GO) as a charismatic heterogeneous metal-free carbocatalyst.Microwave-assisted synthesis reduces the reaction times from hours (conventional heating) to minutes. The use of a heterogeneous catalyst allows for efficient recovery and reusability up to eight cycles without losing much of its effectiveness, thereby enhancing sustainability. This method offers high product yields of diverse substrates with low catalyst loading and simple work-up and catalyst handling. In addition, the antimicrobial activities for some randomly taken compounds have also been studied against gram positive bacteria Staphylococcos aureus (MTCC96) and gram negative bacteria Escherichia coli(MTCC730).