PURINES, PYRIMIDINES, AND CONDENSED SYSTEMS BASED ON THEM. 9. CONCERNING THE SYNTHESIS OF 1-R-PYRAZOLOPYRIMIDINE-4,6-DIONES

Article abstract of DOI:10.1007/BF00473940

1-Ethyl-3-aryl-5-methylpyrazolo<3,4-d>pyrimidine-4,6-diones are formed in small amounts, together with the expected hydrazones, in the reaction of 3-methyl-6-(1-ethylhydrazino)uracil with aromatic aldehydes in ethanol.The yield of these diones increases substantially when the reaction is carried out in acetic acid and sodium nitrite is subsequently added to the mixture.A change in the temperature conditions makes it possible to direct this reaction toward the formation of 1-ethyl-3-aryl-6-methylpyrimido<5,7-e>as-triazine-5,7-diones.