(NH 4 ) 2 S 2 O 8 promoted tandem radical cyclization of quinazolin-4(3 H )-ones with oxamic acids for the construction of fused quinazolinones under metal-free conditions.

A novel cascade radical addition/cyclization reaction of non-activated olefins and oxamic acids has been proposed. Under transition metal-free conditions, 36 quinazolinone derivatives containing an amide moiety were successfully synthesized, with the highest yield being 81%. This method involves the preparation of aminoacyl fused quinazolinone derivatives under mild conditions, offering advantages such as a high yield, a broad substrate compatibility, and a high atom economy.