Stable σ-Adducts of 5-Azauracil with C-Nucleophiles.

The heating of 5-azauracil 1 with malonamide in butanol resulted in 1,2,3,4,5,6-hexahydro-6-(dicarbamoylmethyl)-1,3,5-triazine-2,4-dione 3. Under conditions of acid catalysis, compound 1 reacted with o-phenylenediamine, pyrrogallol, resorcinol and phenylhydrazine derivatives to form the corresponding 6-derivatives of 1,2,3,4,5,6-hexahydro-1,3,5-triazine-2,4-dione.