Highly Efficient, One Pot, Solvent and Catalyst, Free Synthesis of Novel Quinazoline Derivatives under Ultrasonic Irradiation and Their Vasorelaxant Activity Isolated Thoracic Aorta of Rat

New quinazoline derivatives were prepared by one pot reaction of anthranilic acid, acetic anhydride and primary amines, under ultrasonic irradiation. As a result, Ultrasonic irradiation has led to affordable, clean synthesis of a variety of target compounds in much higher yields, than traditional methods. This method has numerous advantages: such as higher yields, shorter reactions time, and easier work-up. Several structural classes among these compounds were identified to have vasorelaxant activity. In this respect, all of the newly synthesized quinazolinone derivatives displayed vasorelaxant properties on the isolated thoracic rat aorta. The IC50 of compounds 2a (-6.00 ± 0.55), 2g (-7.31 ± 0.94), 2n (-7.15 ± 0.81) and 2p (-7.77 ± 0.31) was comparable to that seen in the Acetylcholine (-7.13 ± 0.14). The structures of the newly synthesized compounds were confirmed by IR, 1H NMR, 13C NMR, mass spectral studies, elemental analysis, and melting point.