Course and scope of the sugar exchange reaction in purine nucleosides

Abstract

The transfer of the purine moiety in 2′,3′-O-isopropylidene nucleosides from their sugar to another, inducible by a halogenose and mercuric cyanide, is evaluated with respect to scope and limitations. Mechanistically relevant data are presented that strongly indicate the reaction to proceed via N7,N9-bis-glycosylated intermediates 6, from which the ribose is subsequently expelled as the 1,5-anhydrosugar.