A Novel Nucleophilic Displacement of Benzoate by Sulfur During Thiation of 3-Deazauridine Tribenzoate

Abstract

Thiation of 3-deazauridine tribenzoate [4-hydroxy-1-(2,3,5-tri-O-benzoyl-β-D-ribofuranosyl)-2-pyridone] (1a) with phosphorus pentasulfide in moist β-picoline followed by debenzoylation gave 2-mercapto-1-(2-deoxy-β-D-arabinofuranosyl)pyridine-4-thione-S2 → 2′-cyclonucleoside (2b). Thus, replacement of the heterocyclic oxygens by sulfur followed by a novel nucleophilic displacement of benzoate by mercaptide in the hot basic solution must have occurred.