Microwave-induced perchloric acid catalyzed novel solvent-free synthesis of 4-aryl-3,4-dihydropyrimidones via biginelli condensation

We report here domestic microwave‐induced perchloric acid‐catalyzed solvent‐free synthesis of various 4‐aryl‐3,4‐dihydropyrimidones for the first time. In all the cases the yields are excellent and the mechanism follows a simple Biginelli condensation to produce the dihydropyrimidones in a few seconds. This procedure has been successfully employed to synthesize the mitotic kinesin EG5 inhibitor Monastrol (Figure I).