The Chemistry of Phthalide-3-carboxylic Acid. V. The Reaction of the Acid With Imines

Abstract

Phthalide-3-carboxylic acids decarboxylate readily in the presence of imines, the product depending on the solvent used. In dimethyl sulfoxide, or in the absence of solvent, at 130�, the product is the 3-alkyl 3-hydroxyisoindolone or its dehydration product, but in acetic anhydride at 130� the product is a mixture of diastereoisomeric 3-acetylarninoalkylphthalides. The reactions can be applied to the synthesis of natural products such as the isoindoloisoquinoline and phthalideisoquinoline alkaloids.