Microwave-assisted chemoselective synthesis and photophysical properties of 2-arylazo-biphenyl-4-carboxamides from hydrazonals

RSC Adv. 2023 Aug 22;13(36):25054-25068. doi: 10.1039/d3ra04558g. eCollection 2023 Aug 21.

Abstract

The reaction of 3-oxo-2-arylhydrazonopropanals with acetoacetanilide in an equimolar ratio, under DBU/1,4-dioxane/microwave irradiation reaction conditions, resulted in chemoselective formation of 4-arylazo-5-hydroxy-benzamide derivatives. The structures of the obtained biphenyl-4-carboxamides were characterized by several spectroscopic techniques including IR, 1H- and 13C-NMR, MS and HRMS, and X-ray single crystals of three examples. The photophysical properties of the new products were also evaluated, with a particular focus on their absorption and emission spectra, which provided valuable information regarding their optical properties. The new compounds emitted 513-549 nm green fluorescence in acetone solution under UV irradiation.