Abstract
Our previous method of prepraring azapyrimidine nucleosides is suitable for the preparation of 2-β-D-ribofuranosyl-5-amino-as-triazine-3 (2H)-one (6-azacytidine) (V). For the preparation of 2-β-D-ribofuranosyl-as-triazine-3, 5 (2H, 4H)-dione (6-azauridine) (VI), however, an alternative route by way of 2-(2', 3', 5'-tri-O-benzoyl-β-D-ribofuranosyl)-5-methylmercapto-as-triazine-3 (2H)-one (III) was found to be more convenient than the previous one. The procedure was also improved.
