Synthesis of tryptanthrin appended dispiropyrrolidine oxindoles and their antibacterial evaluation

Abstract

The synthesis of sixteen tryptanthrin appended dispiropyrrolidine oxindoles, employing [3 + 2] cycloaddition of tryptanthrin-derived azomethine ylides with isatilidenes, and their detailed antibacterial evaluation is described. The in vitro antibacterial activities of the compounds were evaluated against ESKAPE pathogens and clinically relevant drug-resistant MRSA/VRSA strains, from which the bromo-substituted dispiropyrrolidine oxindole 5b (MIC = 0.125 μg mL⁻¹) was found to be a potent molecule against S. aureus ATCC 29213 with a good selectivity index.