Nano-Cuo–Au-catalyzed solvent-free synthesis of α-aminophosphonates and evaluation of their antioxidant and α-glucosidase enzyme inhibition activities

ABSTRACT

A new green and efficient method has been developed for the synthesis of α-aminophosphonates through one-pot three-component Kabachnik–Fields reaction. It involves the reaction of a 2-aminophenol with different substituted aromatic aldehydes and dimethyl phosphite in the presence of nanocopper oxide–gold (CuO–Au) catalyst under solvent-free conditions at 60 °C. Nano-CuO–Au catalyst was found to have many advantages like high activity, simple workup, and good (87%) to very high yields (96%). The products were characterized by IR, ¹H, ¹³C, and ³¹P NMR spectra and elemental analysis. All the synthesized compounds were screened for in vitro antioxidant and α-glucosidase inhibition activities. The compound 4b showed higher 2,2-diphenyl-1-picrylhydrazyl and H₂O₂ radical scavenging activity and compound 4e showed higher NO radical scavenging activity than the standard ascorbic acid. The compound 4j has much higher α-glucosidase enzyme inhibition activity than the standard acarbose.

GRAPHICAL ABSTRACT

KEYWORDS:

• α-Aminophosphonates
• α-glucosidase enzyme inhibition activity
• antioxidant activity
• Kabachnik–Fields reaction
• nano-CuO–Au

Acknowledgments

The authors wish to express their grateful thanks to Prof. C. Devendranath Reddy for his helpful discussions, and the author Prof. C. Suresh Reddy renders gratitude to Science and Engineering Research Board (SERB), New Delhi, India, for their support (DST No: SB/S1/OC-96/2013, Dt: 05-11-2014).

Additional information

Funding

One of the authors Dr S. Santhisudha expresses sincere thanks to the Science and Engineering Research Board (SERB), New Delhi, India, for providing financial assistance (DST No: PDF/2016/000102, Dt: 11-07-2016).