Sonochemical synthesis of pyrido[2,3-d:6,5-d']-dipyrimidines catalyzed by [HNMP](+)[HSO4](-) and their antimicrobial activity studies.

In this study, the one-pot four-component reaction of aromatic aldehyde, 2-thiobarbituric acid, ammonium acetate in the presence of a catalytic amount of [H-NMP](+)[HSO4](-) under ultrasonic irradiation in water is reported. In the present procedure, the pyrido[2,3-d:6,5-d']dipyrimidine derivatives were purely produced as valuable products. The process proved to be simple, environmentally friendly, efficient and high to excellent yielding. Moreover, some of the synthetic compounds were investigated and revealed important antimicrobial activity of prepared products.