The first iodine improved 1,3-dipolar cycloaddition: facile and novel synthesis of 2-substituted benzo[f]isoindole-4,9-diones

The first novel protocol of the synthesis of 2-substituted benzo[f]isoindole-4,9-dione framework via the one-pot, 1,3-dipolar cycloaddition of quinones, paraformaldehyde and N-substituted amino ester hydrochlorides in the present of iodine at refluxing acetonitrile was reported. All these reactions proceed with good to excellent yields. The promising results obtained 1,3-dipolar cycloaddition will have the potential application in natural product exhibiting important biological activities.