Base-Controlled Synthesis of Fluorescent Acridone Derivatives via Formal (4 + 2) Cycloaddition.

A transition-metal-free formal (4 + 2) cycloaddition for the direct assembly of acridone derivatives has been developed from simple and easily accessible o -aminobenzamides and 2-(trimethylsilyl)aryl triflates. The base played an important role in the selective controlled synthesis of N -H and N -aryl acridones. A preliminary study on the fluorescence properties of N -aryl acridones demonstrated that they could be used as fluorescent materials with a broad emission range.