One‐pot Synthesis of 3,4‐Dihydropyrimidin‐2(1H)‐one Using TsOH as a Catalyst under Microwave Irradiation

A series of Biginelli compounds was synthesized using TsOH as a catalyst under microwave irradiation. This simple method provided the title compounds in 86%–98% yields by the reaction of aromatic aldehydes with 1,3-carbonyl compound and urea. The structure of 4o was determined by single crystal X-ray diffraction analysis.