Cascade Reaction of Isatins with Heterocyclic Ketene Aminals: Synthesis of Imidazopyrroloquinoline Derivatives

A concise and efficient route for the synthesis of highly substituted imidazopyrroloquinoline derivatives by simply refluxing a reaction mixture of different types of isatins and heterocyclic ketene aminals (HKAs) by acetic acid was developed. This method is suitable for combinatorial and parallel syntheses in drug discovery; consequently, a library of highly substituted imidazopyrroloquinoline derivatives was rapidly constructed using the present protocol.