Microwave-Assisted Synthesis of Azoniaspiro Compounds Using a Novel Catalyst, 1-Azaphenothiazine

Abstract

Azaphenothiazine catalyses the intramolecular cyclization of N-(bromoalkyl)phthalimides in the presence of anhydrous K2CO3 to form spiro cyclic quaternary ammonium salts, namely azoniaspiro compounds, under microwave irradiation. A novel and ecofriendly method was developed for the synthesis of azoniaspiro compounds, and the role of azaphenothiazine as a catalyst in such reactions has been established for the first time. In the future, this protocol can be extended to the synthesis of various substituted N-heterocycles by hydrolyzing the resulting azoniaspiro compounds.