Nucleosides. II. Direct Synthesis of 5-Substituted 2', 5'-Anhydro-1-β-D-arabinofuranosyluracils from Uridine Derivatives

Abstract

Reaction of 5-substituted 2', 5'-dichloro-2', 5'-dideoxyuridines (1a-d) with methanolic sodium hydroxide under reflux afforded the corresponding 5-substituted 2', 5'-anhydro-1-β-D-arabino-furanosyluracils (3a-d) in high yield. On the other hand, reaction of 5-substituted uridines (5a-d) with the Vilsmeier-Haack reagent (POCl₃/DMF) followed by treatment with methanolic sodium hydroxide under reflux led directly to the formation of the corresponding anhydrouridines (3a-d) in good yield.