Acid-Catalyzed Synthesis of Isatoic Anhydride-8-Secondary Amides Enables IASA Transformations for Medicinal Chemistry.

Quinazolin-dione-N-3-alklyl derivatives are the core scaffolds for several categories of bioactive small molecules, but current synthetic methods are costly, involve environmental hazards, and are not uniformly scalable. Here, we report an inexpensive, flexible, and scalable method for the one-pot synthesis of substituted quinazolin-dione-N-3-alkyls (isomers of isatoic-8-secondary amides (IASAs)) from isatin that take advantage of in situ capture of imidic acid under acidic conditions. We further show that this method can be used for the synthesis of a wide variety of derivatives with medicinal uses.