Synthesis of some D-mannofuranosyl and D-lyxofuranosyl imidazole and adenine nucleosides and anomalous 1H nuclear magnetic resonance spectra of related anomers

Abstract

Ethyl 1-α- and -β-D-2′,3′-O-isopropylidene mannofuranosyl imidazole-4-carboxylates have been prepared from corresponding 2′,3′:5′,6′-di-O-isopropylidene derivatives and, after N-acetylation, converted by periodate and borohydride into the corresponding 1-α- and -β-D-2′,3′-O-isopropylidene lyxofuranosyl imidazole-4-carboxylates; the anomeric configuration of the nucleosides was confirmed by ¹H n.m.r. and optical rotation studies and by conversion of the 2′,3′:5′,6′-O-isopropylidene mannoside esters with ammonia into the corresponding amides which were converted by sequences of reactions into the corresponding 1-α- and -β-D-mannofuranosyl adenines.