Selective synthesis of quinazolinones by using fluorescein catalyst under mild conditions

Abstract

A fast and highly efficient method for the synthesis of functionalized dihydroquinazolinone and quinazolinone via photocatalysis has been reported. Fluorescein has respectively participated in the cyclization and dehydrogenation reactions, and different products were obtained in the presence and absence of light. 2-Phenyl-2,3-dihydroquinazolin-4(1H)-one was synthesized by fluorescein without visible light. Subsequently, quinazolinone was further obtained with the dehydrogenation of dihydroquinazolinone by fluorescein induce. The reaction process was highly efficient, and a wide range of quinazolinones could be synthesized with a highest yield of 98% in just 1 h under visible light conditions. Furthermore, the reaction could be extended to the gram level by up to 88%. This protocol provides an alternative route for preparing quinazolinone derivatives by employing photocatalytic methods for synthesizing quinazolinones without additional oxidants, acids and metals.