DMAP-Catalyzed Domino Reactions of α-Chloroaldoxime O-methanesulfonates and 2-Aminobenzoic acid for the Synthesis of Quinazolinediones

Abstract

Quinazolinediones are one of the most important N-containing natural products with a wide range of biological activities. The structural features of quinazolinedione include a phenyl ring fused with urea moiety. Various quinazolinediones were achieved from 2-aminobenzoic acids and α-chloroaldoxime O-methanesulfonates via DMAP-catalyzed domino reactions under mild reaction conditions. The reaction pathways plausibly involved nucleophilic addition, Tiemann rearrangement, an intramolecular C–O formation followed by O-acylisourea rearrangement. The electronic effect on the nitrogen of 2-aminobenzoic acids and the electrophilicity of α-chloroaldoxime O-methanesulfonates both significantly played an important role to the reaction efficiency. Moreover, our methodology could be applied to alternatively achieve a building block for biologically active quinazolinedione.