PREPARATION OF NUCLEOSIDES VIA ISOPROPYLIDENE SUGAR DERIVATIVES .3. SYNTHESIS OF 9-BETA-D-GULOFURANOSYLADENINE AND 9-ALPHA-L-LYXOFURANOSYLADENINE

2,3:5,6-Di-O-isopropylidenegulonolactone was reduced to the corresponding gulofuranose derivative with sodium borohydride. A halogenose was prepared with thionyl chloride and condensed with 6-benzamidochloromercuripurine. Removal of all blocking groups yielded 9-β-D-gulofuranosyladenine. An intermediate in the reaction sequence, 9-(2,3-O-isopropylidene-β-D-gulofuranosyl)adenine was treated with sodium periodate and sodium borohydride to give, after removal of the isopropylidene group, 9-α-L-lyxofuranosyladenine. Assignment of anomeric configuration to this compound was made on the basis that it was shown to be the enantiomorph of 9-α-D-lyxofuranosyladenine, the structure of which had been demonstrated previously. Knowledge of the anomeric configuration of the α-L- and α-D-pentofuranosyl nucleosides enabled assignment of anomeric configuration to the hexofuranosyl nucleosides from which they were derived, 9-β-D-gulofuranosyladenine and 9-α-D-mannofuranosyladenine, respectively. © 1968, American Chemical Society. All rights reserved.