For the determination of the structure of domoic acid, the acid was submitted to ozonolysis in aqueous solution. On concentration of the reaction mixture for separation of the reaction products, the procedure at as low a temperature as possible afforded Ls-arabo-2-carboxy-3-carboxymethyl-4-acetylpyrrolidine (IV), m.p. 197°, with propionaldehyde (III), proved as its 2, 4-dinitrophenylhydrazone. ... [Show full abstract] When the concentration was made under heat over a direct flame, Ls-xylo-2-carboxy-3-carboxymethyl-4-acetylpyrrolidine (V), m.p. 211°, was obtained besides propionaldehyde (III).
The ultraviolet and infrared spectral analyses of domoic acid indicated that the structure of domoic acid is Ls-arabo-2-carboxy-3-carboxymethyl-4-(1-methyl-2-car-boxy-1, 3-hexadienyl)pyrrolidine.