Synthesis of N-Unsubstituted and N3-Substituted Quinazoline-2,4(1H,3H)-diones from o-Aminobenzamides and CO2 at Atmospheric Pressure and Room Temperature

The unprecedented metal-free synthesis of both N-unsubstituted and N3-substituted quinazoline-2,4(1H,3H)-diones from o-aminobenzamides and CO2 under atmospheric pressure at room temperature is developed. This protocol easily allows for variations of functional groups (including alkyl, aryl, and heterocycle groups) at the N3-position to accommodate the construction of many important drugs and bioactive compounds. The reaction features eco-friendliness, substrate scope tolerance, and versatility and can be implemented even at the gram scale.