Synthesis of Beta‐Enaminoketones and Enaminoesters Catalyzed by Brønsted Acids Ammonium Chloride and Glycine Hydrochloride

Abstract Beta‐enaminoketones and beta‐enaminoesters are valuable as drug candidates and intermediates in the synthesis of nitrogen heterocycles and multidentate ligands. These compounds were obtained by the addition of aliphatic or aromatic amines to beta‐diketo‐derivatives, catalyzed by either ammonium chloride or glycine hydrochloride, both inexpensive and nontoxic catalysts. The reactions were conducted under neat conditions allowing efficient work‐up, catalyst recovery and the possibility for reaction telescoping. The process yielded beta‐enaminoketones and beta‐enaminoesters in high to excellent yields with a mechanism involving the formation of key intermediates that facilitate the condensation.