Synthesis of novel spirooxindolo-pyrrolidines, pyrrolizidines, and pyrrolothiazoles via a regioselective three-component [3+2] cycloaddition and their preliminary antimicrobial evaluation.

A series of spirooxindolo-pyrrolidines, pyrrolizidines, and pyrrolothiazoles hybrid compounds were prepared in good yields by regioselective, three-component, 1,3-dipolar cycloaddition reactions between α, β-unsaturated ketones with furanyl substituents and unstable azomethine ylides, which were generated in situ from isatin and various types of amino acids. The synthesized compounds were screened for their antibacterial activities against a spectrum of pathogens. Preliminary studies identified compound 5c as a potent antimicrobial agent against drug-resistant bacteria. In addition, molecular docking studies indicated that compound 5c showed strong interactions with the active sites of lanosterol demethylase, dihydrofolate reductase, and topoisomerase II. This study provides an effective entry to the rapidly construction of a chemical library of heterocycles and compound 5c is one potent antibacterial lead for subsequent optimization.