their coronaryvasodilator activity are described. Amidophosphonates 4a-m, lactam amidophosphonates 7a-1, and diamide dilactam 10 were prepared, and their coronaryvasodilator activity was assessed in dogs. Many compounds exhibited coronaryvasodilator activity superior to that of fostedil. Among them, the 2-oxopyrrolidine derivative 7a was the most effective compound. Its action as a coronary vasodilator