Abstract
Acid hydrolysis of cytosinine gave each one mole of cytosine, levulinic acid, ammonia and carbon dioxide. Reduction of cytosinine with PtO2 afforded a mixture of dihydro-cytosinine, 3-amino-tetrahydropyran-2-carboxylic acid and cytosine. Ozonolysis of N, N'-diacetylcytosinine methyl ester, followed by oxidation with hydrogen peroxide and acid hydrolysis gave erythro-D-β-hydroxyaspartic acid. These data permitted the assignment of structure (I) for cytosinine. Acid hydrolysis of uracinine gave uracil instead of cytosine, therefore, the structure (II) could be assigned to uracinine. Some stereochemical features and mechanism of levulinic acid formation were discussed.
