A Simple One-Pot Method for 6-Oxopurine Ribonucleoside Synthesis: Control and Mechanism of Isomer Distribution

Abstract
Combination of bis(trimethylsilyl)acetamide as a silylating reagent and trimethylsilyl trifluoromethanesulfonate as a catalyst forms an exceptionally stable system for a facile one-pot preparation of 6-oxopurine ribonucleosides. The 7β isomer of the ribonucleosides, formed first, is converted into the 9β isomer presumably via the 7,9-diribonucleoside. The procedure affords both 7β and 9β isomers, but finally yields the 9β isomer as the main product.