Sonochemical Synthesis and DFT Study of Novel α-Aminophosphonates Derived from Benzodoxazol-2(3H)-one

A series of novel α-aminophosphonate derivatives of benzodoxazol-2(3H)-one was synthesized through the ultrasound-assisted one-pot Kabachnik–Fields reaction between 6-aminobenzodoxazol-2(3H)-one, aromatic aldehydes, and diethyl phosphite, using the ionic liquid TEAA as the solvent and catalyst. The structure of the synthesized compounds was confirmed by IR and 1H, 13C, and 31P NMR spectroscoscopy and elemental analysis. The chemical reactivity of the molecules was assessed through DFT calculations at the B3LYP/6-311G(d,p) level of theory via an analysis of the HOMO–LUMO energies, energy gaps, and global reactivity indices. Molecular electrostatic potential maps were also generated to determine reactive centers in the synthesized compounds. The computational analysis identified compound 4b as the most chemically reactive.