Effective utilization of water extract of red mud (WERM) as an alternative sustainable basic medium in Michael addition reaction

Abstract

An expedient and eco-friendly protocol for the construction of CC and CS bonds has been developed by Michael addition of chalcones with various nucleophiles like malononitrile, 1,3-dimethylbarbituric acid, nitromethane, benzyl cyanide, and thiols using water extract of red mud (WERM) at room temperature. Red mud is the by-product abundantly generated as wastes in aluminium industries and this is the first report where WERM is utilized profitably as an alternative basic medium for Michael addition reaction. This reaction method is not only environmentally benign and cost-effective as WERM is derived from waste material but also tolerated electronically diverse functional groups. Other notable advantages of the present protocol are operational simplicity, no column chromatographic purification, excellent yields within short reaction times, reusability of reaction media, and scale up synthesis. Additionally, this green protocol has also been applied to synthesize highly substituted pyridine derivatives.

Keywords

• Chalcones
• Michael addition
• Pyridine
• Red Mud
• Sustainable chemistry
• WERM