l-Proline-catalyzed three-component synthesis of condensed imidazoles

A one-pot, efficient and high yielding procedure for the synthesis of 3,4-dihydro-2-arylimidazo[4,5-b]indole and 2-aryl-1H-imidazo[4,5-f][1,10]phenanthroline is reported. The procedure proceeded by the multicomponent reaction of aromatic aldehydes, indoline-2,3-dione or 1,10-phenanthroline-5,6-dione and ammonium acetate catalyzed by l-proline under ultrasonic irradiation. Conveniency, simplicity, rapidity and cleanliness of the procedure for the synthesis of imidazole derivatives are the advantages of this study.