The Synthesis and Bioactivity of Dimethyl (2,3- Dihydrobenzo[b][1,4]Dioxin-6-Yl)(Aryl Amino)Methylphosphonates

Abstract

A new series of α-aminophosphonates have been synthesized by a one-pot three-component reaction of 2,3-dihydrobenzo[b][1,4]dioxine-6-carbaldehyde, various amines, and dimethyl phosphite by using nano-TiO₂ as a catalyst under solvent-free conditions at 50°C. The major advantages of the present method are high yields, short reaction times, recyclable catalyst, and solvent-free reaction conditions. Among these new structurally diversified set of α-aminophosphonates, dimethyl (2,3-dihydrobenzo[b][1,4]dioxin-6-yl)(3-nitrophenylamino) methylphosphonate and dimethyl (2,3-dihydrobenzo[b][1,4]dioxin-6-yl)(4-fluoro-3-nitro-phenyl-amino) methylphosphonate have shown higher antioxidant activity in diphenyl picryl hydrazyl (DPPH) scavenging, reducing power assay, and lipid peroxidation methods.

GRAPHICAL ABSTRACT

Keywords:

• α-Aminophosphonates
• nano-TiO₂
• solvent-free
• antioxidant activity

Acknowledgments

The authors express their grateful thanks to Prof. C. D. Reddy, Department of Chemistry, Sri Venkateswara University, Tirupati, for his helpful discussions and also thank DRDO, New Delhi, for providing financial assistance (ERIP/ER/1103894M/ 01/1346). The authors also express their thanks to Prof. Ch. Appa Rao and S. Swapna, Department of Bio-chemistry, S.V. University, Tirupati for conducting antioxidant activity.

[Supplementary materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements for the following free supplemental files: Additional text and figures.]