Synthesis of Diverse Ureas from Amines and CO 2 at Atmospheric Pressure and Room Temperature.

A metal-free method is developed to perform the synthesis of urea derivatives utilizing CO ₂ as the C1 building block at atmospheric pressure and room temperature. In addition to diverse symmetric and dissymmetric ureas, benzimidazolones and quinazolinone can also be easily prepared using this protocol. Most importantly, the gram-scale preparation of fungicide pencycuron and antipsychotic drug pimavanserin proceeded smoothly under the mild conditions.