SiO2@MWCNTs employing for the synthesis of spironinhydrines using multicomponent reaction: Investigation of biological activity

In this research, SiO2@MWCNTs promoted green synthesis of novel spirobarbitoric acid using multicomponent reaction of ninhydrine, secondary amines and alkylidene barbitoric acid in water at room temperature in excellent yield. The antioxidant properties and antimicrobial ability of the synthesized compounds are investigated. For this purpose, the radical scavenging activity of four derivatives was studied by radical trapping of diphenylpicrylhydrazine and ferric reduction power experiments. Disk diffusion test on Gram-positive and Gram-negative bacteria employed to investigate antibacterial activities of five derivatives. Also, the catalytic activity of the green synthesized SiO2@MWCNTs was evaluated in the reduction of organic pollutants such as 4-nitrophenol (4-NP) in water at mild conditions. The results indicated that the biosynthesized NCs have very high and effective catalytic activity for organic pollutants within few seconds. The current procedure has the benefits for instance excellent yield of reaction, green media and easy separation of product and catalyst.