Abstract
β-(3, 5-Dioxo-1, 2, 4-oxadiazolidin-2-yl)-L-alanine (Ia) was proposed for quisqualic acid (I), an acidic amino acid isolated from Quisqualis Fructus on the basis of chemical and physiochemical properties, and confirmed by synthesis. A new hydroxyureido derivative, 2-amino-3-(1-hydroxyureido) propionic acid (II), was obtained by an alkaline treatment of I. 2-Amino-3-(3-hydroxyureido) propionic acid (IIb) and isoquisqualic acid, [β-(3, 5-dioxo-1, 2, 4-oxadiazolidin-4-yl) alanine](Ib) were also synthesized.
