Pyrimidine derivatives and related compounds. Part 47. A new synthesis of xanthines and pyrrolo[3,2-d]pyrimidines by intramolecular cyclisation of 6-substituted 5-nitrouracil derivatives
of 6-[2-(ethoxycarbonyl, acetyl, and cyano) ethyl] uracil (8h–j) with triethylamine led to the formation of the corresponding 6-vinyluracil (11 a–c). A one-step synthesis of the 7-hydroxy-9-deazaxanthines (9a–e) was accomplished by the treatment of the sodium salt (7) with arylalkyl chlorides in the presence of potassium carbonate in dry DMF. Deoxygenation of the 7-hydroxy-9-deazaxanthines (9a–e) smoothly