Copper oxide nanoparticle catalysed synthesis of imidazo[1,2-a]pyrimidine derivatives, their optical properties and selective fluorescent sensor towards zinc ion

Abstract

Synthesis of biologically active fused imidazo[1,2-a]pyrimidines were achieved via A3 coupling involving 2-aminobenzimidazole, aldehyde and terminal alkyne, followed by 6-endo-dig cyclization using copper oxide nanoparticles under solvent free condition. Further optical properties of imidazo[1,2-a]pyrimidines were studied which showed the effect of electron-donating and electron-withdrawing substitution on the fluorescence intensities of these compounds. Out of 20 compounds, 2,4-bis(4-methoxyphenyl)benzo[4,5]imidazo[1,2-a]pyrimidine can act as a fluorescent sensor for zinc ion with detection limit 4.74 μM, which is much lower than the maximum allowable zinc concentration in drinking water by WHO.