In addition to our recent report on a series of rationally designed benzylindolyldiketo acids acting as potent HIV-1 integrase strand transfer inhibitors, we disclose the results obtained with novel compounds chemically modified on the diketo acid moiety in order to investigate its influence on the biological activity and cytotoxicity. The activity of designed and synthesized 4-[(1-benzyl-1H-indol-3-yl)carbonyl]-3-hydroxyfuran-2(5H)-one derivatives lies in the micromolar range with regard to HIV IN enzymatic activity. The microwave-assisted synthesis was employed in some steps of the chemical procedures.