Abstract: Aryl diketo acid derivatives are one of the most promising HIV-1 integrase(IN) inhibitors. With a view to substitute the critical diketo acid pharmacophore with the diketo benzimidazole unit, the coupling reaction of compound 4 with o-phenylenediamine was carried out. However, the reaction product, compound 5, was confirmed to be 3-{[3-(phenylsulfonamido)benzoyl]methylidene}-3,4-dihydroquinoxaline-2(1H)-one rather than the 2-benzimidazole derivative by using X-ray diffraction. Owing to its low solubility in water, the evaluation of the anti-HIV IN activity of the synthesized compound 5 could not be carried out. Consequently, the ion-binding properties of compound 5 in the absence of HIV-1 IN were investigated with UV-Vis spectroscopy in organic solvents. The results show that such a compound can selectively recognize Cu²⁺.

Key words: Diketo acid, Quinoxalone derivative, X-ray crystal structure, Cu²⁺ recognition