Synthesis and spectral studies of biologically active organophosphorus derivatives of substituted 4-(2-hydroxyphenylamino)-2H-chromen-2-one

Abstract Phosphorus-heterocycles are of great interest for the discovery of potent bioactive agents. This study reports the synthesis of a new category of oxthiazaphosphinines 3a-d + 3'a-d, oxazaphosphorines 4a-d, and azaphosphinines 5a-d incorporated with thiocoumarin by cyclocondensation reactions of Lawesson's reagent with bifunctional compounds 2a-d containing mobile hydrogens. The newly synthesized compounds were established by spectroscopic methods (1D, 2D NMR, and HRMS) and screened for acetylcholinesterase inhibition. Among these, the mixture 3d + 3'd has shown a significant anti-AChE activity comparable to that of malathion (IC₅₀ = 52.63 ± 0.1 μg/mL and IC₅₀ = 49.5 ± 0.01 μg/mL), respectively.