21271-36-3 Ethyl 3-((4-oxo-3-phenyl-4H-pyrazino(1,2-a)pyrimidin-2-yl)oxy)propionate Propionic acid, 3-((4-oxo-3-phenyl-4H-pyrazino(1,2-a)pyrimidin-2-yl)oxy)-, ethyl ester